Aggregator

Issued at 2100 UTC WED JUL 31 2024 000 WTPZ23 KNHC 312041 TCMEP3 TROPICAL STORM CARLOTTA FORECAST/ADVISORY NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032024 2100 UTC WED JUL 31 2024 TROPICAL STORM CENTER LOCATED NEAR 16.2N 108.0W AT 31/2100Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 305 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1003 MB MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT. 34 KT....... 40NE 30SE 0SW 30NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 16.2N 108.0W AT 31/2100Z AT 31/1800Z CENTER WAS LOCATED NEAR 15.9N 107.7W FORECAST VALID 01/0600Z 16.8N 109.8W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 20NE 0SE 0SW 0NW. 34 KT... 50NE 40SE 20SW 40NW. FORECAST VALID 01/1800Z 17.3N 111.8W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 40NE 30SE 0SW 30NW. 34 KT... 70NE 60SE 40SW 60NW. FORECAST VALID 02/0600Z 17.7N 113.9W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 15NE 0SE 0SW 15NW. 50 KT... 40NE 30SE 30SW 40NW. 34 KT... 70NE 60SE 50SW 60NW. FORECAST VALID 02/1800Z 17.8N 116.0W MAX WIND 80 KT...GUSTS 100 KT. 64 KT... 20NE 10SE 10SW 20NW. 50 KT... 50NE 30SE 30SW 40NW. 34 KT... 90NE 70SE 60SW 90NW. FORECAST VALID 03/0600Z 17.8N 118.2W MAX WIND 85 KT...GUSTS 105 KT. 50 KT... 45NE 30SE 30SW 45NW. 34 KT...100NE 70SE 70SW 90NW. FORECAST VALID 03/1800Z 17.8N 120.2W MAX WIND 85 KT...GUSTS 105 KT. 50 KT... 45NE 35SE 35SW 45NW. 34 KT...100NE 90SE 90SW 100NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 125 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 04/1800Z 18.3N 122.2W MAX WIND 75 KT...GUSTS 90 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT... 80NE 70SE 70SW 80NW. OUTLOOK VALID 05/1800Z 19.3N 124.0W MAX WIND 65 KT...GUSTS 80 KT. 50 KT... 40NE 35SE 30SW 35NW. 34 KT... 80NE 70SE 60SW 70NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 16.2N 108.0W NEXT ADVISORY AT 01/0300Z $$ FORECASTER PAPIN

WW 0579 Status Updates
STATUS REPORT ON WW 579 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 W 9V9 TO 30 W ABR TO 50 NE ABR TO 25 WNW VVV TO 35 E AXN TO 35 NW BRD TO 35 W BJI. ..LEITMAN..07/31/24 ATTN...WFO...FGF...ABR...MPX... STATUS REPORT FOR WS 579 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC009-011-023-057-059-065-067-073-093-095-097-121-141-145-149- 151-171-173-312140- MN . MINNESOTA COUNTIES INCLUDED ARE BENTON BIG STONE CHIPPEWA HUBBARD ISANTI KANABEC KANDIYOHI LAC QUI PARLE MEEKER MILLE LACS MORRISON POPE SHERBURNE STEARNS STEVENS SWIFT WRIGHT YELLOW MEDICINE SDC013-017-025-029-037-039-051-057-059-091-115-312140- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO CLARK CODINGTON DAY DEUEL GRANT HAMLIN HAND MARSHALL SPINK Read more

WW 0579 Status Updates
STATUS REPORT ON WW 579 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 W 9V9 TO 30 W ABR TO 50 NE ABR TO 25 WNW VVV TO 35 E AXN TO 35 NW BRD TO 35 W BJI. ..LEITMAN..07/31/24 ATTN...WFO...FGF...ABR...MPX... STATUS REPORT FOR WS 579 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC009-011-023-057-059-065-067-073-093-095-097-121-141-145-149- 151-171-173-312140- MN . MINNESOTA COUNTIES INCLUDED ARE BENTON BIG STONE CHIPPEWA HUBBARD ISANTI KANABEC KANDIYOHI LAC QUI PARLE MEEKER MILLE LACS MORRISON POPE SHERBURNE STEARNS STEVENS SWIFT WRIGHT YELLOW MEDICINE SDC013-017-025-029-037-039-051-057-059-091-115-312140- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BROWN BUFFALO CLARK CODINGTON DAY DEUEL GRANT HAMLIN HAND MARSHALL SPINK Read more

Frederick County residents were urged by the Director of the County’s Division of Energy and the Environment to voluntarily conserve water since the Metropolitan Washington Council of Governments issued a drought watch on July 29. WFMD-AM (Frederick, Md.), July 31, 2024

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Wed Jul 31 2024 Valid 312000Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSOURI VALLEY AND UPPER MIDWEST... ...SUMMARY... Severe-weather risk continues from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes ongoing potential for large to very large hail across parts of the northern/central Plains, aside from a more prevalent risk of damaging winds, some of which could be significantly severe (75+ mph). ...Discussion... Prior outlook areas/reasoning continue to largely reflect current thinking for the remainder of the period, with rather minor areal adjustments made in various areas to reflect evolution of ongoing convection. The primary/more substantial change to the outlook is being implemented across the Minnesota area and vicinity -- largely as related to a convective cluster now moving east-northeastward across western portions of the Gopher State. With a moderately unstable airmass indicated ahead of this convection -- all the way to the Canadian border -- it appears that severe risk will extend farther north and east than initially anticipated (in line with recent WW issuance across portions of northern Minnesota). ..Goss.. 07/31/2024 .PREV DISCUSSION... /ISSUED 1130 AM CDT Wed Jul 31 2024/ ...Northern Plains into the Upper Midwest and Mid Mississippi Valley... A seasonably strong mid/upper level trough over the northern High Plains late this morning will continue to progress eastward across the Dakotas/NE and the Upper Midwest through tonight. At the surface, a cold front is forecast to move southeastward across parts of the northern/central Plains through the day, while a lee trough advances eastward across parts of the southern High Plains by late this afternoon. These surface features, combined with ascent attendant to the mid/upper-level trough, should serve as forcing mechanisms for severe thunderstorms today. Ongoing convection across parts of ND/SD into central NE may still be somewhat elevated. But, modifying the 12Z sounding from ABR shows that the airmass across the eastern Dakotas ahead of the cold front is rapidly destabilizing, and this activity should pose at least some severe hail threat in the short term. Upwards of 3000-4000 J/kg of MLCAPE will likely be present across eastern SD and vicinity by early afternoon as daytime heating further erodes lingering MLCIN. Weak low-level winds should gradually veer and modestly strengthen to around 30-40 kt at midlevels as the shortwave trough approaches from the west. This combination of very strong to locally extreme instability will support intense severe thunderstorms this afternoon, including multiple supercells posing a threat for very large hail initially (up to 2-3 inches in diameter). Additional robust convective development should occur southwestward near the cold front into parts of south-central NE/north-central KS, with large hail and severe wind gusts expected. With time, multiple thunderstorm interactions and mergers should lead to one or more bowing clusters consolidating from eastern SD/NE into southwest MN and parts of western/central IA. A swath of severe/damaging winds appears likely with any cluster that can develop. Significant severe wind gusts of 75+ mph appear plausible given the steep low/mid-level lapse rates forecast, and a reservoir of very strong to extreme buoyancy that will likely be present. An intense MCS with a continued severe wind threat could persist tonight across southern MN into IA, and perhaps northern MO into IL. ...Central Plains into the Southern High Plains... Large-scale ascent will become more modest with southward extent across the central Plains into the Southern High Plains. Even so, isolated to widely scattered thunderstorms should develop along the cold front and lee trough by late this afternoon. With weaker deep-layer shear compared to locations farther north, overall thunderstorm mode may tend to be more multicellular versus supercellular. Regardless, moderate to strong instability and sufficient shear should support some threat for isolated hail and severe wind gusts with any robust convection that can develop. ...Midwest/Lower Ohio Valley into the Central/Southern Appalachians... Similar to prior days, a belt of modestly enhanced mid-level northwesterly flow will persist today from parts of the Midwest into the Lower OH Valley and central/southern Appalachians. Outside of ongoing late morning convection, much of these areas will have a moist and rather unstable airmass present this afternoon as daytime heating continues. Multiple organized, severe wind producing clusters/MCSs may occur through this evening across these regions. However, confidence in a more concentrated severe wind corridor remains too low to include higher severe probabilities (Enhanced Risk) with this update. A cluster moving across western into central IN has recently shown signs of weakening, with outflow surging well ahead of reflectivity cores. Visible satellite imagery also shows outflow from convection in west-central IL surging southward. A separate area of thunderstorms in southern IA may also pose an isolated hail wind threat as this activity spreads into a gradually destabilizing airmass across northeast MO. It appears plausible that any of this ongoing convection may restrengthen through the afternoon as it continues generally east-southeastward. Additional robust thunderstorms may develop along the various outflow boundaries. Any cluster that can form and be sustained should pose a threat for mainly damaging winds given the favorable thermodynamic environment coupled with modest but sufficient deep-layer shear. ...Southern Arizona... An upper low centered near Baja California and ongoing early day storms across parts of northwest Mexico may influence thunderstorm development later this afternoon, with a moist airmass located particularly across parts of southeast/south-central AZ. With a well mixed boundary layer and steepened low/mid-level lapse rates expected, some of this activity could produce isolated strong to severe wind gusts and blowing dust this afternoon into early evening. Read more