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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 PM CDT Mon Apr 21 2025 Valid 220100Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong storms may develop across portions of Iowa later tonight, but hail should generally remain below severe levels. ...01z Update... Notable short-wave trough is currently located over the northern High Plains. This feature is shifting east as a 500mb speed max translates across SD toward northern IA. Scattered weak convection is noted ahead of this feature, arcing from eastern SD into northeast NE. LLJ should increase across eastern NE/western IA this evening in response to the short wave, and a corridor of low-level warm advection should aid additional convection downstream. Forecast soundings suggest elevated buoyancy will increase such that robust updrafts are possible. While steep lapse rates favor hail production, instability may be a bit too weak to warrant more than marginally severe hail. For these reasons will not introduce severe probabilities ..Darrow.. 04/22/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 PM CDT Mon Apr 21 2025 Valid 220100Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong storms may develop across portions of Iowa later tonight, but hail should generally remain below severe levels. ...01z Update... Notable short-wave trough is currently located over the northern High Plains. This feature is shifting east as a 500mb speed max translates across SD toward northern IA. Scattered weak convection is noted ahead of this feature, arcing from eastern SD into northeast NE. LLJ should increase across eastern NE/western IA this evening in response to the short wave, and a corridor of low-level warm advection should aid additional convection downstream. Forecast soundings suggest elevated buoyancy will increase such that robust updrafts are possible. While steep lapse rates favor hail production, instability may be a bit too weak to warrant more than marginally severe hail. For these reasons will not introduce severe probabilities ..Darrow.. 04/22/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 PM CDT Mon Apr 21 2025 Valid 220100Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong storms may develop across portions of Iowa later tonight, but hail should generally remain below severe levels. ...01z Update... Notable short-wave trough is currently located over the northern High Plains. This feature is shifting east as a 500mb speed max translates across SD toward northern IA. Scattered weak convection is noted ahead of this feature, arcing from eastern SD into northeast NE. LLJ should increase across eastern NE/western IA this evening in response to the short wave, and a corridor of low-level warm advection should aid additional convection downstream. Forecast soundings suggest elevated buoyancy will increase such that robust updrafts are possible. While steep lapse rates favor hail production, instability may be a bit too weak to warrant more than marginally severe hail. For these reasons will not introduce severe probabilities ..Darrow.. 04/22/2025 Read more

Warm, dry weather allowed a northeast Kansas farmer to get corn in the ground. Brownfield Ag Network (Jefferson City, Mo.), April 21, 2025

No watches are valid as of Mon Apr 21 22:24:02 UTC 2025.

No Mesoscale Discussions are in effect as of Mon Apr 21 22:24:02 UTC 2025.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0443 PM CDT Mon Apr 21 2025 Valid 231200Z - 291200Z A gradual amplification of upper-level troughing is expected across the western CONUS this week. The primary fire weather threat will be across the Southwest as dry, southwest flow gradually increases through the weekend. Complementary ridging across the eastern U.S. will provide a more efficient mechanism for moist return flow to the Great Plains and Midwest. The relatively rich boundary layer moisture east of the Rockies interacting with a nascent low pressure system forming day 4/Thursday will promote widespread rainfall across much of the Central Plains eastward into the Midwest and Northeastern U.S. by day 6/Saturday as the low translates eastward. ...Southwest... Synoptic setup with amplifying upper-level trough and enhanced southwest flow will support increasing fire weather concerns across much of the Southwest. Effects on fuels from recent rain and higher elevation snow mainly north of the I-40 corridor will wane as dry conditions settle back into the region. At least Elevated fire weather conditions are expected each day across portions of Arizona and New Mexico through the weekend, with corresponding Critical probabilities where forecast confidence is higher based on latest model guidance consensus. ...Southern Georgia and Florida... Fire weather concerns will remain across the Florida Peninsula as a subtropical high to the east provides persistent east-southeast winds across the state through early next week. Marine influence will mitigate fire weather concerns along the Florida Atlantic Coast but central and western Florida could see overlapping of sufficient winds, low daytime relative humidity of 30-40 percent and persistently dry fuels to promote at least Elevated fire weather threat day 3 through day 5. Drying and curing of available fuels across the Florida Panhandle into southern Georgia will continue through the week but winds are not expected to be particularly strong with no Critical probabilities added. ..Williams/Lyons.. 04/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0443 PM CDT Mon Apr 21 2025 Valid 231200Z - 291200Z A gradual amplification of upper-level troughing is expected across the western CONUS this week. The primary fire weather threat will be across the Southwest as dry, southwest flow gradually increases through the weekend. Complementary ridging across the eastern U.S. will provide a more efficient mechanism for moist return flow to the Great Plains and Midwest. The relatively rich boundary layer moisture east of the Rockies interacting with a nascent low pressure system forming day 4/Thursday will promote widespread rainfall across much of the Central Plains eastward into the Midwest and Northeastern U.S. by day 6/Saturday as the low translates eastward. ...Southwest... Synoptic setup with amplifying upper-level trough and enhanced southwest flow will support increasing fire weather concerns across much of the Southwest. Effects on fuels from recent rain and higher elevation snow mainly north of the I-40 corridor will wane as dry conditions settle back into the region. At least Elevated fire weather conditions are expected each day across portions of Arizona and New Mexico through the weekend, with corresponding Critical probabilities where forecast confidence is higher based on latest model guidance consensus. ...Southern Georgia and Florida... Fire weather concerns will remain across the Florida Peninsula as a subtropical high to the east provides persistent east-southeast winds across the state through early next week. Marine influence will mitigate fire weather concerns along the Florida Atlantic Coast but central and western Florida could see overlapping of sufficient winds, low daytime relative humidity of 30-40 percent and persistently dry fuels to promote at least Elevated fire weather threat day 3 through day 5. Drying and curing of available fuels across the Florida Panhandle into southern Georgia will continue through the week but winds are not expected to be particularly strong with no Critical probabilities added. ..Williams/Lyons.. 04/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0443 PM CDT Mon Apr 21 2025 Valid 231200Z - 291200Z A gradual amplification of upper-level troughing is expected across the western CONUS this week. The primary fire weather threat will be across the Southwest as dry, southwest flow gradually increases through the weekend. Complementary ridging across the eastern U.S. will provide a more efficient mechanism for moist return flow to the Great Plains and Midwest. The relatively rich boundary layer moisture east of the Rockies interacting with a nascent low pressure system forming day 4/Thursday will promote widespread rainfall across much of the Central Plains eastward into the Midwest and Northeastern U.S. by day 6/Saturday as the low translates eastward. ...Southwest... Synoptic setup with amplifying upper-level trough and enhanced southwest flow will support increasing fire weather concerns across much of the Southwest. Effects on fuels from recent rain and higher elevation snow mainly north of the I-40 corridor will wane as dry conditions settle back into the region. At least Elevated fire weather conditions are expected each day across portions of Arizona and New Mexico through the weekend, with corresponding Critical probabilities where forecast confidence is higher based on latest model guidance consensus. ...Southern Georgia and Florida... Fire weather concerns will remain across the Florida Peninsula as a subtropical high to the east provides persistent east-southeast winds across the state through early next week. Marine influence will mitigate fire weather concerns along the Florida Atlantic Coast but central and western Florida could see overlapping of sufficient winds, low daytime relative humidity of 30-40 percent and persistently dry fuels to promote at least Elevated fire weather threat day 3 through day 5. Drying and curing of available fuels across the Florida Panhandle into southern Georgia will continue through the week but winds are not expected to be particularly strong with no Critical probabilities added. ..Williams/Lyons.. 04/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0443 PM CDT Mon Apr 21 2025 Valid 231200Z - 291200Z A gradual amplification of upper-level troughing is expected across the western CONUS this week. The primary fire weather threat will be across the Southwest as dry, southwest flow gradually increases through the weekend. Complementary ridging across the eastern U.S. will provide a more efficient mechanism for moist return flow to the Great Plains and Midwest. The relatively rich boundary layer moisture east of the Rockies interacting with a nascent low pressure system forming day 4/Thursday will promote widespread rainfall across much of the Central Plains eastward into the Midwest and Northeastern U.S. by day 6/Saturday as the low translates eastward. ...Southwest... Synoptic setup with amplifying upper-level trough and enhanced southwest flow will support increasing fire weather concerns across much of the Southwest. Effects on fuels from recent rain and higher elevation snow mainly north of the I-40 corridor will wane as dry conditions settle back into the region. At least Elevated fire weather conditions are expected each day across portions of Arizona and New Mexico through the weekend, with corresponding Critical probabilities where forecast confidence is higher based on latest model guidance consensus. ...Southern Georgia and Florida... Fire weather concerns will remain across the Florida Peninsula as a subtropical high to the east provides persistent east-southeast winds across the state through early next week. Marine influence will mitigate fire weather concerns along the Florida Atlantic Coast but central and western Florida could see overlapping of sufficient winds, low daytime relative humidity of 30-40 percent and persistently dry fuels to promote at least Elevated fire weather threat day 3 through day 5. Drying and curing of available fuels across the Florida Panhandle into southern Georgia will continue through the week but winds are not expected to be particularly strong with no Critical probabilities added. ..Williams/Lyons.. 04/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0443 PM CDT Mon Apr 21 2025 Valid 231200Z - 291200Z A gradual amplification of upper-level troughing is expected across the western CONUS this week. The primary fire weather threat will be across the Southwest as dry, southwest flow gradually increases through the weekend. Complementary ridging across the eastern U.S. will provide a more efficient mechanism for moist return flow to the Great Plains and Midwest. The relatively rich boundary layer moisture east of the Rockies interacting with a nascent low pressure system forming day 4/Thursday will promote widespread rainfall across much of the Central Plains eastward into the Midwest and Northeastern U.S. by day 6/Saturday as the low translates eastward. ...Southwest... Synoptic setup with amplifying upper-level trough and enhanced southwest flow will support increasing fire weather concerns across much of the Southwest. Effects on fuels from recent rain and higher elevation snow mainly north of the I-40 corridor will wane as dry conditions settle back into the region. At least Elevated fire weather conditions are expected each day across portions of Arizona and New Mexico through the weekend, with corresponding Critical probabilities where forecast confidence is higher based on latest model guidance consensus. ...Southern Georgia and Florida... Fire weather concerns will remain across the Florida Peninsula as a subtropical high to the east provides persistent east-southeast winds across the state through early next week. Marine influence will mitigate fire weather concerns along the Florida Atlantic Coast but central and western Florida could see overlapping of sufficient winds, low daytime relative humidity of 30-40 percent and persistently dry fuels to promote at least Elevated fire weather threat day 3 through day 5. Drying and curing of available fuels across the Florida Panhandle into southern Georgia will continue through the week but winds are not expected to be particularly strong with no Critical probabilities added. ..Williams/Lyons.. 04/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

Gov. Spencer Cox issued an executive order Monday, April 21, aiming to bolster Utah’s wildfire preparedness and coordination ahead of the anticipated fire season. KSL Newsradio (Salt Lake City, Utah), April 21, 2025

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Apr 21 2025 Valid 212000Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES...AND PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms are possible today across the upper Ohio Valley/lower Great Lakes and parts of the Southeast. Damaging winds and marginally severe hail are the primary risks. ...20Z Update... The Marginal risk in the Lower Great Lakes was trimmed behind the eastward-moving frontal band of convection. Elsewhere, the forecast remains on track and minimal changes were made with this update. For details on the near-term severe risk, reference MCDs #512 and #513. ..Weinman.. 04/21/2025 .PREV DISCUSSION... /ISSUED 1124 AM CDT Mon Apr 21 2025/ ...Upper OH Valley... Morning surface analysis and satellite imagery show a cold front sweeping eastward across OH. Considerable cloud cover is present ahead of the front, but a narrow corridor of heating immediately ahead of the front will allow a period of heating - promoting scattered thunderstorms. Low-level moisture is limited with dewpoints only in the 50s, and forecast soundings show CAPE values generally below 1000 J/kg. Nevertheless, strong low and mid-level winds and considerable vertical shear will promote a risk of a few organized/severe storms capable of damaging wind gusts and perhaps a tornado or two. Refer to upcoming MCD #511 for further details. ...LA/MS/AL/GA/TN... The aforementioned surface cold front extends southeastward across west TN. A relatively moist air mass is present ahead of the front from southeast LA into parts of MS/AL and middle/east TN, although considerable cloud cover will limit heating. Most 12z models suggest scattered thunderstorms will form in this zone during the late afternoon and evening, with sufficient CAPE for a few robust updrafts. Low and mid level winds are not particularly strong, and large scale forcing is weak. This should limit the overall organization and severity of storms, but a few cells may produce gusty winds and hail. ...SD... Water vapor imagery shows a mid-level shortwave trough over WY approaching SD. Forcing ahead of this feature will likely lead to scattered high-based showers and thunderstorms across eastern WY and western/central SD this afternoon and evening. There is some chance that a storm or two could produce locally damaging wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Apr 21 2025 Valid 212000Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES...AND PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms are possible today across the upper Ohio Valley/lower Great Lakes and parts of the Southeast. Damaging winds and marginally severe hail are the primary risks. ...20Z Update... The Marginal risk in the Lower Great Lakes was trimmed behind the eastward-moving frontal band of convection. Elsewhere, the forecast remains on track and minimal changes were made with this update. For details on the near-term severe risk, reference MCDs #512 and #513. ..Weinman.. 04/21/2025 .PREV DISCUSSION... /ISSUED 1124 AM CDT Mon Apr 21 2025/ ...Upper OH Valley... Morning surface analysis and satellite imagery show a cold front sweeping eastward across OH. Considerable cloud cover is present ahead of the front, but a narrow corridor of heating immediately ahead of the front will allow a period of heating - promoting scattered thunderstorms. Low-level moisture is limited with dewpoints only in the 50s, and forecast soundings show CAPE values generally below 1000 J/kg. Nevertheless, strong low and mid-level winds and considerable vertical shear will promote a risk of a few organized/severe storms capable of damaging wind gusts and perhaps a tornado or two. Refer to upcoming MCD #511 for further details. ...LA/MS/AL/GA/TN... The aforementioned surface cold front extends southeastward across west TN. A relatively moist air mass is present ahead of the front from southeast LA into parts of MS/AL and middle/east TN, although considerable cloud cover will limit heating. Most 12z models suggest scattered thunderstorms will form in this zone during the late afternoon and evening, with sufficient CAPE for a few robust updrafts. Low and mid level winds are not particularly strong, and large scale forcing is weak. This should limit the overall organization and severity of storms, but a few cells may produce gusty winds and hail. ...SD... Water vapor imagery shows a mid-level shortwave trough over WY approaching SD. Forcing ahead of this feature will likely lead to scattered high-based showers and thunderstorms across eastern WY and western/central SD this afternoon and evening. There is some chance that a storm or two could produce locally damaging wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Apr 21 2025 Valid 212000Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES...AND PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms are possible today across the upper Ohio Valley/lower Great Lakes and parts of the Southeast. Damaging winds and marginally severe hail are the primary risks. ...20Z Update... The Marginal risk in the Lower Great Lakes was trimmed behind the eastward-moving frontal band of convection. Elsewhere, the forecast remains on track and minimal changes were made with this update. For details on the near-term severe risk, reference MCDs #512 and #513. ..Weinman.. 04/21/2025 .PREV DISCUSSION... /ISSUED 1124 AM CDT Mon Apr 21 2025/ ...Upper OH Valley... Morning surface analysis and satellite imagery show a cold front sweeping eastward across OH. Considerable cloud cover is present ahead of the front, but a narrow corridor of heating immediately ahead of the front will allow a period of heating - promoting scattered thunderstorms. Low-level moisture is limited with dewpoints only in the 50s, and forecast soundings show CAPE values generally below 1000 J/kg. Nevertheless, strong low and mid-level winds and considerable vertical shear will promote a risk of a few organized/severe storms capable of damaging wind gusts and perhaps a tornado or two. Refer to upcoming MCD #511 for further details. ...LA/MS/AL/GA/TN... The aforementioned surface cold front extends southeastward across west TN. A relatively moist air mass is present ahead of the front from southeast LA into parts of MS/AL and middle/east TN, although considerable cloud cover will limit heating. Most 12z models suggest scattered thunderstorms will form in this zone during the late afternoon and evening, with sufficient CAPE for a few robust updrafts. Low and mid level winds are not particularly strong, and large scale forcing is weak. This should limit the overall organization and severity of storms, but a few cells may produce gusty winds and hail. ...SD... Water vapor imagery shows a mid-level shortwave trough over WY approaching SD. Forcing ahead of this feature will likely lead to scattered high-based showers and thunderstorms across eastern WY and western/central SD this afternoon and evening. There is some chance that a storm or two could produce locally damaging wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Apr 21 2025 Valid 212000Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES...AND PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms are possible today across the upper Ohio Valley/lower Great Lakes and parts of the Southeast. Damaging winds and marginally severe hail are the primary risks. ...20Z Update... The Marginal risk in the Lower Great Lakes was trimmed behind the eastward-moving frontal band of convection. Elsewhere, the forecast remains on track and minimal changes were made with this update. For details on the near-term severe risk, reference MCDs #512 and #513. ..Weinman.. 04/21/2025 .PREV DISCUSSION... /ISSUED 1124 AM CDT Mon Apr 21 2025/ ...Upper OH Valley... Morning surface analysis and satellite imagery show a cold front sweeping eastward across OH. Considerable cloud cover is present ahead of the front, but a narrow corridor of heating immediately ahead of the front will allow a period of heating - promoting scattered thunderstorms. Low-level moisture is limited with dewpoints only in the 50s, and forecast soundings show CAPE values generally below 1000 J/kg. Nevertheless, strong low and mid-level winds and considerable vertical shear will promote a risk of a few organized/severe storms capable of damaging wind gusts and perhaps a tornado or two. Refer to upcoming MCD #511 for further details. ...LA/MS/AL/GA/TN... The aforementioned surface cold front extends southeastward across west TN. A relatively moist air mass is present ahead of the front from southeast LA into parts of MS/AL and middle/east TN, although considerable cloud cover will limit heating. Most 12z models suggest scattered thunderstorms will form in this zone during the late afternoon and evening, with sufficient CAPE for a few robust updrafts. Low and mid level winds are not particularly strong, and large scale forcing is weak. This should limit the overall organization and severity of storms, but a few cells may produce gusty winds and hail. ...SD... Water vapor imagery shows a mid-level shortwave trough over WY approaching SD. Forcing ahead of this feature will likely lead to scattered high-based showers and thunderstorms across eastern WY and western/central SD this afternoon and evening. There is some chance that a storm or two could produce locally damaging wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Apr 21 2025 Valid 212000Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES...AND PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms are possible today across the upper Ohio Valley/lower Great Lakes and parts of the Southeast. Damaging winds and marginally severe hail are the primary risks. ...20Z Update... The Marginal risk in the Lower Great Lakes was trimmed behind the eastward-moving frontal band of convection. Elsewhere, the forecast remains on track and minimal changes were made with this update. For details on the near-term severe risk, reference MCDs #512 and #513. ..Weinman.. 04/21/2025 .PREV DISCUSSION... /ISSUED 1124 AM CDT Mon Apr 21 2025/ ...Upper OH Valley... Morning surface analysis and satellite imagery show a cold front sweeping eastward across OH. Considerable cloud cover is present ahead of the front, but a narrow corridor of heating immediately ahead of the front will allow a period of heating - promoting scattered thunderstorms. Low-level moisture is limited with dewpoints only in the 50s, and forecast soundings show CAPE values generally below 1000 J/kg. Nevertheless, strong low and mid-level winds and considerable vertical shear will promote a risk of a few organized/severe storms capable of damaging wind gusts and perhaps a tornado or two. Refer to upcoming MCD #511 for further details. ...LA/MS/AL/GA/TN... The aforementioned surface cold front extends southeastward across west TN. A relatively moist air mass is present ahead of the front from southeast LA into parts of MS/AL and middle/east TN, although considerable cloud cover will limit heating. Most 12z models suggest scattered thunderstorms will form in this zone during the late afternoon and evening, with sufficient CAPE for a few robust updrafts. Low and mid level winds are not particularly strong, and large scale forcing is weak. This should limit the overall organization and severity of storms, but a few cells may produce gusty winds and hail. ...SD... Water vapor imagery shows a mid-level shortwave trough over WY approaching SD. Forcing ahead of this feature will likely lead to scattered high-based showers and thunderstorms across eastern WY and western/central SD this afternoon and evening. There is some chance that a storm or two could produce locally damaging wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Apr 21 2025 Valid 212000Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES...AND PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms are possible today across the upper Ohio Valley/lower Great Lakes and parts of the Southeast. Damaging winds and marginally severe hail are the primary risks. ...20Z Update... The Marginal risk in the Lower Great Lakes was trimmed behind the eastward-moving frontal band of convection. Elsewhere, the forecast remains on track and minimal changes were made with this update. For details on the near-term severe risk, reference MCDs #512 and #513. ..Weinman.. 04/21/2025 .PREV DISCUSSION... /ISSUED 1124 AM CDT Mon Apr 21 2025/ ...Upper OH Valley... Morning surface analysis and satellite imagery show a cold front sweeping eastward across OH. Considerable cloud cover is present ahead of the front, but a narrow corridor of heating immediately ahead of the front will allow a period of heating - promoting scattered thunderstorms. Low-level moisture is limited with dewpoints only in the 50s, and forecast soundings show CAPE values generally below 1000 J/kg. Nevertheless, strong low and mid-level winds and considerable vertical shear will promote a risk of a few organized/severe storms capable of damaging wind gusts and perhaps a tornado or two. Refer to upcoming MCD #511 for further details. ...LA/MS/AL/GA/TN... The aforementioned surface cold front extends southeastward across west TN. A relatively moist air mass is present ahead of the front from southeast LA into parts of MS/AL and middle/east TN, although considerable cloud cover will limit heating. Most 12z models suggest scattered thunderstorms will form in this zone during the late afternoon and evening, with sufficient CAPE for a few robust updrafts. Low and mid level winds are not particularly strong, and large scale forcing is weak. This should limit the overall organization and severity of storms, but a few cells may produce gusty winds and hail. ...SD... Water vapor imagery shows a mid-level shortwave trough over WY approaching SD. Forcing ahead of this feature will likely lead to scattered high-based showers and thunderstorms across eastern WY and western/central SD this afternoon and evening. There is some chance that a storm or two could produce locally damaging wind gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Mon Apr 21 2025 Valid 212000Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND LOWER GREAT LAKES...AND PORTIONS OF THE SOUTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms are possible today across the upper Ohio Valley/lower Great Lakes and parts of the Southeast. Damaging winds and marginally severe hail are the primary risks. ...20Z Update... The Marginal risk in the Lower Great Lakes was trimmed behind the eastward-moving frontal band of convection. Elsewhere, the forecast remains on track and minimal changes were made with this update. For details on the near-term severe risk, reference MCDs #512 and #513. ..Weinman.. 04/21/2025 .PREV DISCUSSION... /ISSUED 1124 AM CDT Mon Apr 21 2025/ ...Upper OH Valley... Morning surface analysis and satellite imagery show a cold front sweeping eastward across OH. Considerable cloud cover is present ahead of the front, but a narrow corridor of heating immediately ahead of the front will allow a period of heating - promoting scattered thunderstorms. Low-level moisture is limited with dewpoints only in the 50s, and forecast soundings show CAPE values generally below 1000 J/kg. Nevertheless, strong low and mid-level winds and considerable vertical shear will promote a risk of a few organized/severe storms capable of damaging wind gusts and perhaps a tornado or two. Refer to upcoming MCD #511 for further details. ...LA/MS/AL/GA/TN... The aforementioned surface cold front extends southeastward across west TN. A relatively moist air mass is present ahead of the front from southeast LA into parts of MS/AL and middle/east TN, although considerable cloud cover will limit heating. Most 12z models suggest scattered thunderstorms will form in this zone during the late afternoon and evening, with sufficient CAPE for a few robust updrafts. Low and mid level winds are not particularly strong, and large scale forcing is weak. This should limit the overall organization and severity of storms, but a few cells may produce gusty winds and hail. ...SD... Water vapor imagery shows a mid-level shortwave trough over WY approaching SD. Forcing ahead of this feature will likely lead to scattered high-based showers and thunderstorms across eastern WY and western/central SD this afternoon and evening. There is some chance that a storm or two could produce locally damaging wind gusts. Read more

MD 0513 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF NWRN NE INTO S CNTRL SD
Mesoscale Discussion 0513 NWS Storm Prediction Center Norman OK 0101 PM CDT Mon Apr 21 2025 Areas affected...parts of nwrn NE into s cntrl SD Concerning...Severe potential...Watch unlikely Valid 211801Z - 212100Z Probability of Watch Issuance...5 percent SUMMARY...Scattered thunderstorm activity is beginning to develop this afternoon. Although this is likely to remain weak in intensity, it may still contribute to a few locally strong to briefly severe strength surface gusts by 2-4 PM MDT. DISCUSSION...Within larger-scale mid-level troughing spreading across and east of the northern Rockies, it appears that one embedded speed maximum (50+ kt around 500 mb) will continue an east-northeastward propagation from east central Wyoming toward south central South Dakota this afternoon. Despite limited low-level moisture, insolation beneath cold mid-level air (including temperatures cooling below -20C around 500 mb) is contributing to weak destabilization of the boundary layer, which continues to warm and deepen with insolation across the Sand Hills of Nebraska into the high plains south and east of the Black Hills. Deepening high-based convective development is underway, with lightning already noted in activity as far south as the Scottsbluff NE vicinity. This probably will continue, with some additional intensification while spreading eastward through mid to late afternoon. As boundary-layer mixing/deepening progresses, the sub-cloud environment will become increasingly conducive to the downward transfer of momentum associate with the stronger mid-level flow and the negatively buoyant downdrafts, contributing to potential for a few gusts in excess of 50 kt. ..Kerr/Hart.. 04/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...LBF...UNR...CYS... LAT...LON 44290180 44330078 43749980 42810038 41600227 41460368 43030383 43290285 44150233 44290180 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more