SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CDT Fri Aug 01 2025 Valid 031200Z - 091200Z A mid/upper-level trough is currently forecast to remain over portions of the Pacific Northwest from Day 3/Sunday through Day 8/Friday. Meanwhile, mid/upper-level ridging, initially centered over portions of the Desert Southwest Day 3/Sunday, is forecast to gradually build across portions of the Great Basin through the week. There remains a large amount of intra/inter-model and run-to-run variability, regarding how far northwest the ridge is able to build. ...Great Basin... Several days of hot, dry, and breezy conditions are expected atop receptive fuels across portions of the Great Basin and adjacent areas - near the base of the aforementioned trough. Elevated to at least locally critical conditions are possible from Day 3/Sunday through Day 5/Tuesday, with 40% probabilities for Critical conditions each day. While fire weather concerns may continue across these areas beyond Day 5/Tuesday, confidence is currently too low to introduce probabilities for Critical conditions due to the uncertain trough/ridge evolution. ...Dry Thunderstorms... Isolated dry thunderstorms will remain possible across portions of northern California, far northwestern Nevada, southeastern Oregon, and southwestern Idaho Day 3/Sunday and perhaps into Day 4/Monday before thunderstorm potential decreases across the West. Isolated dry thunderstorms are also possible across portions of Arizona Day 5/Tuesday and Day 6/Wednesday, where fuels remain critically receptive. Though, uncertainty regarding placement/coverage is currently too large to introduce probabilities for dry thunderstorms. ..Elliott.. 08/01/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

1 month ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CDT Fri Aug 01 2025 Valid 031200Z - 091200Z A mid/upper-level trough is currently forecast to remain over portions of the Pacific Northwest from Day 3/Sunday through Day 8/Friday. Meanwhile, mid/upper-level ridging, initially centered over portions of the Desert Southwest Day 3/Sunday, is forecast to gradually build across portions of the Great Basin through the week. There remains a large amount of intra/inter-model and run-to-run variability, regarding how far northwest the ridge is able to build. ...Great Basin... Several days of hot, dry, and breezy conditions are expected atop receptive fuels across portions of the Great Basin and adjacent areas - near the base of the aforementioned trough. Elevated to at least locally critical conditions are possible from Day 3/Sunday through Day 5/Tuesday, with 40% probabilities for Critical conditions each day. While fire weather concerns may continue across these areas beyond Day 5/Tuesday, confidence is currently too low to introduce probabilities for Critical conditions due to the uncertain trough/ridge evolution. ...Dry Thunderstorms... Isolated dry thunderstorms will remain possible across portions of northern California, far northwestern Nevada, southeastern Oregon, and southwestern Idaho Day 3/Sunday and perhaps into Day 4/Monday before thunderstorm potential decreases across the West. Isolated dry thunderstorms are also possible across portions of Arizona Day 5/Tuesday and Day 6/Wednesday, where fuels remain critically receptive. Though, uncertainty regarding placement/coverage is currently too large to introduce probabilities for dry thunderstorms. ..Elliott.. 08/01/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC MD 1862

1 month ago
MD 1862 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL MISSISSIPPI AND WESTERN ALABAMA
Mesoscale Discussion 1862 NWS Storm Prediction Center Norman OK 0207 PM CDT Fri Aug 01 2025 Areas affected...Central Mississippi and western Alabama Concerning...Severe potential...Watch unlikely Valid 011907Z - 012100Z Probability of Watch Issuance...5 percent SUMMARY...Damaging winds are becoming increasingly possible across central Mississippi and far western Alabama. However, the overall magnitude of this threat should remain sufficiently limited to preclude watch issuance. DISCUSSION...Recent imagery from KGWX and KDGX shows convective clusters developing across central MS as a diffuse cold front begins to impinge on a moist and uncapped air mass. Recent RAP and HRRR forecast soundings appear to be capturing near-surface temperature/dewpoint trends well, and suggest MLCAPE values are within the 2000-2500 J/kg range with theta-e deficits on the order of 20-25 K, and 0-1 km lapse rates approaching 8 C/km. This thermodynamic environment is favorable for strong wet downbursts, which will become increasingly likely as cold pool amalgamation/upscale growth continues with the gradual intensification of the emerging thunderstorm cluster. Sporadic damaging wind gusts (most likely within the 45-55 mph range) appear likely, though a gust or two near 60 mph will be possible as this activity spreads south/southeast through late afternoon. Very weak flow aloft sampled by regional VWPs (generally 15 knots or less through 7 km) will limit the potential for appreciable storm organization and more substantial peak gusts, though isolated instances wind damage are anticipated. ..Moore/Smith.. 08/01/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BMX...MOB...MEG...JAN... LAT...LON 33309046 33698935 34058826 33908768 33628738 33148734 32588746 32238767 32038798 31918858 31918916 31978955 32048988 32189019 32379042 32629053 32859063 32999064 33309046 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH Read more

SPC MD 1861

1 month ago
MD 1861 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR SOUTHERN VIRGINIA INTO NORTH CAROLINA AND NORTHERN SOUTH CAROLINA
Mesoscale Discussion 1861 NWS Storm Prediction Center Norman OK 0144 PM CDT Fri Aug 01 2025 Areas affected...Far southern Virginia into North Carolina and northern South Carolina Concerning...Severe potential...Watch unlikely Valid 011844Z - 012045Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorms emanating off the Blue Ridge Mountains and developing along a cold front will pose a damaging wind threat through early evening. Watch issuance is not expected. DISCUSSION...Thunderstorm development is well underway along the Blue Ridge Mountains amid a combination of diurnal destabilization and increasing ascent due to both lift along an approaching baroclinic zone and modest upslope flow. Additionally, thunderstorms are beginning to slowly intensify along a weak cold front across northern SC where temperatures have warmed into the low 90s. Although deep-layer flow is fairly weak (generally less than 20 knots through 6 km), somewhat uniform ascent along the terrain/front is promoting sufficient convective coverage/spacing to favor multicell clusters with consolidated cold pools. The expectation through early evening is for one or more clusters to emerge off the terrain and propagate south/southeast into the more buoyant air mass across the Carolinas ahead of the primary baroclinic zone. As this occurs, a combination of high PWAT values (well above 2.0 inches) and steepening 0-2 km lapse rates should promote wet downbursts capable of transient strong to severe gusts (mainly 45-65 mph) within the stronger clusters. While wind damage is probable, the poor kinematic environment should limit the overall propensity for severe convection and precludes watch issuance. ..Moore/Smith.. 08/01/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MHX...RAH...ILM...RNK...CAE...GSP... LAT...LON 33687892 33588016 33988178 34288245 34528268 34838282 35118283 35438264 35858221 36408152 37008045 37148005 37177980 37107962 36977939 36807927 36627916 36407912 36177914 35927911 35697897 35517885 35297865 35167840 34977805 34817776 34627758 34487755 34337753 34147757 33917782 33807822 33687892 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more

SPC Aug 1, 2025 2000 UTC Day 1 Convective Outlook

1 month ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 01 2025 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE CENTRAL HIGH PLAINS INTO WESTERN SOUTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the High Plains this afternoon and evening. Large to very large hail, a couple of tornadoes, and severe gusts are possible. ...20z Update... The forecast largely remains on track. The primary update was to introduce 5% tornado probabilities across portions of northwest SD ahead of a pronounced MCV where initial stages of thunderstorm development are noted in recent GOES/lightning data. Visible imagery shows slowly building cumulus within the southeasterly flow regime ahead of the MCV as temperatures warm into the mid/upper 70s. Forecast soundings suggest this is adequate for surface-based convection, and depict enlarging hodographs later this evening as the nocturnal jet strengthens. While localized, this environment may be somewhat more favorable for tornadoes compared to adjacent portions of SD. Elsewhere, minimal changes are required. 5% wind probabilities were amended slightly across portions of the Carolinas to better reflect recent thunderstorm development/trends. See the previous discussion below as well as MCDs #1860-1862 for additional details. ..Moore.. 08/01/2025 .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Aug 01 2025/ ...High Plains... Water-vapor imagery late this morning shows a few disturbances undercutting an upper ridge currently over the High Plains/Alberta. An MCV is slowly moving eastward near the MT/WY/SD/ND border, a more pronounced upper trough will remain over the northern Rockies and adjacent high plains of MT, and a more subtle disturbance will move east-northeastward across the central Rockies. A residual frontal zone draped generally south-north abutting the higher terrain is providing a focus for richer moisture east of this boundary over the High Plains. Surface dewpoints will likely range from the mid 50s to the lower 60s across much of the Slight Risk. A belt of slightly stronger westerly upper flow is forecast across the central High Plains which will act to elongate hodographs. Additionally, a plume of steep 700-500 mb lapse rates (7.5 to 9 deg C/km) will contribute to MLCAPE 2000-3000 by mid-late afternoon. The aforementioned low-amplitude disturbance over the central Rockies coupled with low-level upslope flow/orographic effects will result in initial thunderstorm development over the high terrain and the Cheyenne Ridge. The best overlap between buoyancy and shear is expected from western SD into northeast CO/WY/NE Panhandle border region. Model ensemble data suggest a few favored corridors for severe may result. The most notable area may focus near the Cheyenne Ridge and adjacent northeast CO where supercell potential appears greatest. Large to very large hail and a tornado or two are possible with this activity before gradually transitioning to primarily a risk for severe gusts. One other area of interest is across northwest SD, where an MCV moving slowly into the region could result in a focused area of thunderstorms. Increased low-level convergence and low-level vertical shear near this MCV could lead to a greater threat for all severe hazards, including large hail and perhaps a brief tornado or two. ...Carolinas into Georgia-Alabama-Mississippi... A seasonably moist airmass was sampled by 12 UTC area raobs this morning (near 16 g/kg lowest 100-mb mean mixing ratio). Visible-satellite imagery shows extensive low cloud cover across central and eastern NC near and behind the wind shift/cold front. Farther west, initial cumulus field development is noted over the southern Appalachians where strong heating is occurring and farther south/southeast over the Piedmont and to the coastal plain. As temperatures continue to warm through early afternoon, erosion of convective inhibition will result in scattered storms favoring the higher terrain and eventually near the wind shift. High PW (2 inches or greater) and diurnally steepened surface to 1.5 km lapse rates will support a risk for wet microbursts with the more intense water-loaded downdrafts. Localized gusts 50-65 mph are possible and scattered pockets of wind damage may result. Read more
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