Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1139 AM CDT Wed Jul 31 2024 Valid 311700Z - 011200Z The current forecast remains valid and on track. See the previous discussion for further detail. ..Halbert/Squitieri.. 07/31/2024 .PREV DISCUSSION... /ISSUED 0128 AM CDT Wed Jul 31 2024/ ...Synopsis... A midlevel trough will track eastward across the northern Plains, while a related cold front moves east-southeastward across the central Plains. Warm, dry, and breezy post-frontal conditions will develop across portions of the central High Plains during the afternoon -- yielding locally elevated fire-weather conditions. Farther west, a large-scale ridge will build across the western CONUS, favoring warm/dry conditions. However, generally weak surface winds (outside of terrain-favored areas) precludes fire-weather highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Wed Jul 31 2024 Valid 311630Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA AND NEBRASKA INTO SOUTHWEST MINNESOTA AND MUCH OF IOWA... ...SUMMARY... Another active severe weather day is expected from the northern/central Plains and Upper Midwest to the southern Appalachians. This includes 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). ...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. ..Gleason/Moore.. 07/31/2024 Read more

MD 1763 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR CENTRAL INDIANA
Mesoscale Discussion 1763 NWS Storm Prediction Center Norman OK 0956 AM CDT Wed Jul 31 2024 Areas affected...central Indiana Concerning...Severe potential...Watch possible Valid 311456Z - 311630Z Probability of Watch Issuance...40 percent SUMMARY...Locally gusty winds of 40-60 mph are possible across parts of central Indiana through early afternoon. Severe thunderstorm watch issuance is uncertain. DISCUSSION...A cluster of storms near the IL/IN border will continue to track east/southeast the next few hours. Overall structure and organization of this activity has decreased compared to overnight/earlier this morning. Measured wind gusts with this activity have mostly been in the 30-40 kt range, with a couple locally higher gusts. The downstream environment remains weakly to moderately capped with deep-layer flow relatively weak (less than 30 kt effective shear). With continued heating, inhibition should gradually decrease. However, instability and shear are expected to remain somewhat modest. While some minor intensification is possible, timing and coverage of any greater severe risk is uncertain. Severe thunderstorm watch issuance is not expected in the short term, but trends will be monitored and watch issuance is possible later this morning or afternoon if trends increase sufficiently. ..Leitman/Gleason.. 07/31/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IND...LOT...ILX... LAT...LON 40608781 40548737 40188620 39888581 39688583 39328603 39158633 39228677 39308726 39458774 39668799 40088805 40358801 40608781 Read more

WW 0578 Status Updates
STATUS REPORT ON WW 578 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 NE SLO TO 10 S DEC TO 5 WSW HUF. ..LEITMAN..07/31/24 ATTN...WFO...LSX...ILX... STATUS REPORT FOR WS 578 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC023-025-029-033-035-049-079-101-139-159-173-311640- IL . ILLINOIS COUNTIES INCLUDED ARE CLARK CLAY COLES CRAWFORD CUMBERLAND EFFINGHAM JASPER LAWRENCE MOULTRIE RICHLAND SHELBY THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more