Aggregator

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Sat May 17 2025 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO INTO FAR WESTERN TEXAS... Stronger mid-level winds on the southern periphery of a upper-trough will spread over parts of the Southwest and Southern Plains for Tuesday will continue to support a broad fire weather threat across the region. A developing lee trough along with downsloping into the adjacent High Plains will support meteorologically critical fire weather conditions across southeastern Colorado and southwestern Kansas. However, with recent green up and ERCs below the 50th percentile in this area, fire spread potential is reduced. Even so, southwest winds of 25-30 mph and single digit relative humidity should support at least an elevated fire danger concern. ..Williams.. 05/17/2025 .PREV DISCUSSION... /ISSUED 0105 AM CDT Sat May 17 2025/ ...Synopsis... On Sunday, a mid-level trough (and associated wind speed maximum) is forecast to progress across the Four Corners region into the southern High Plains. Deep boundary-layer mixing behind a sharpening dryline and deepening surface cyclone will result in widespread Critical conditions, primarily across southern New Mexico into far West Texas. ...Southern New Mexico into Far West Texas... As the surface cyclone over the southern High Plains deepens and the dryline mixes eastward, surface winds of 20-25 MPH with 5-10% relative humidity are forecast. Fuels will be receptive to rapid wildfire ignition and spread, with ERC percentiles at or exceeding the 80th-90th annual percentiles. There is some suggestion in the 00Z HREF ensemble guidance that winds could reach 30 MPH, though there is not enough confidence at this time to introduce any Extremely Critical highlights. Further east into Texas, meteorological conditions will also reach Critical threshold -- however, current fuels guidance shows fuels are only at or below average, so only Elevated highlights have been maintained at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Sat May 17 2025 Valid 181200Z - 191200Z ...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO INTO FAR WESTERN TEXAS... Stronger mid-level winds on the southern periphery of a upper-trough will spread over parts of the Southwest and Southern Plains for Tuesday will continue to support a broad fire weather threat across the region. A developing lee trough along with downsloping into the adjacent High Plains will support meteorologically critical fire weather conditions across southeastern Colorado and southwestern Kansas. However, with recent green up and ERCs below the 50th percentile in this area, fire spread potential is reduced. Even so, southwest winds of 25-30 mph and single digit relative humidity should support at least an elevated fire danger concern. ..Williams.. 05/17/2025 .PREV DISCUSSION... /ISSUED 0105 AM CDT Sat May 17 2025/ ...Synopsis... On Sunday, a mid-level trough (and associated wind speed maximum) is forecast to progress across the Four Corners region into the southern High Plains. Deep boundary-layer mixing behind a sharpening dryline and deepening surface cyclone will result in widespread Critical conditions, primarily across southern New Mexico into far West Texas. ...Southern New Mexico into Far West Texas... As the surface cyclone over the southern High Plains deepens and the dryline mixes eastward, surface winds of 20-25 MPH with 5-10% relative humidity are forecast. Fuels will be receptive to rapid wildfire ignition and spread, with ERC percentiles at or exceeding the 80th-90th annual percentiles. There is some suggestion in the 00Z HREF ensemble guidance that winds could reach 30 MPH, though there is not enough confidence at this time to introduce any Extremely Critical highlights. Further east into Texas, meteorological conditions will also reach Critical threshold -- however, current fuels guidance shows fuels are only at or below average, so only Elevated highlights have been maintained at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Sat May 17 2025 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING OVER NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHWEST LOUISIANA....... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF UPSTATE NEW YORK AND WESTERN NEW ENGLAND... ...SUMMARY... Severe thunderstorms producing large to very large hail, damaging gusts and a couple of tornadoes are expected across the southern Plains. Additional severe storms are possible across the Northeast. ...20z Update... Adjustments were made to the 20z to remove the Marginal risk across portions of Georgia into South Carolina and across the northeast behind morning convection. The Slight Risk and Moderate Risk were nudged further south in far southern Texas to account for potential for storms to come out of Mexico this evening with potential for large hail and severe winds. Otherwise, the risk areas across the main region of the southern/central Plains were not changed. Thunderstorm development has begun across the dryline from southern/central Texas to the Red River in Oklahoma. See MCD#840 and MCD#838 for more information on the short term risks in these areas. ..Thornton/Hart.. 05/17/2025 .PREV DISCUSSION... /ISSUED 1117 AM CDT Sat May 17 2025/ ...Central TX/Southern OK into the ArkLaTex Region... Morning water vapor loop shows a well-defined shortwave trough over southern AZ tracking northeastward. Ahead of this system, southerly low-level winds and steep lapse rates aloft have established a very moist and extremely unstable air mass from southern OK into central TX. Dewpoints in the low/mid 70s and ample daytime heating will yield afternoon MLCAPE values over 4000 J/kg. As the upper system and associated mid-level jet max approach the dryline, thunderstorms are expected to rapidly develop by mid-afternoon. Splitting supercells capable of very large hail will be the main initial concern, along with damaging winds and a tornado or two. Most model solutions suggest upscale growth of these storms into a bowing MCS by evening, tracking eastward across the ArklaTex region. Have extended the ENH a little farther east to accommodate this scenario, with damaging winds and large hail being the main concerns. This cluster of storms may persist overnight, tracking into central/northern MS. ...Northwest OK... The plume of dense cirrus ahead of the AZ shortwave trough will move east of northwest OK by late afternoon, allowing strong heating and destabilization. This combined with southeasterly low level winds near a retreating warm front will provide a corridor of strong instability and favorable low-level shear for supercell development. The coverage of storms in this area is uncertain and varied between the morning CAM solutions. However, the storms that form will pose a risk of very large hail, damaging winds, and a tornado or two. It is also unclear how far east this threat may persist, with some concern for an MCS tracking into northeast OK overnight. ...NY/New England... A progressive shortwave trough and associated mid-level jet is tracking eastward across the Great Lakes region today. Cooling temperatures aloft and strong daytime heating will lead to pockets of moderate CAPE and steep low/mid level lapse rates. Storms are beginning to form across NY and will move into a progressively more favorable air mass for strong/severe convection (including a few supercells) by mid-afternoon. Locally damaging winds are the main concern, but the strongest cells could also produce hail and perhaps a tornado or two. Refer to MCD #837 for further details. Read more