Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Sun Apr 13 2025 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorm development will be possible on Sunday from the upper Mississippi Valley into the Great Lakes, and from the Intermountain West to the central High Plains. No severe threat is expected. ...DISCUSSION... At mid-levels, a ridge will move through the Great Lakes and lower to mid Mississippi Valley, as a shortwave trough moves through the northern High Plains. At the surface, a low will move into the mid Missouri Valley as a cold front advances southeastward through the central Plains. Head of the front, an axis of low-level moisture will be in place from the Ozarks northward into Minnesota. Surface dewpoints are expected to be in the 40s F over the upper Mississippi Valley, where weak destabilization is expected. Along the northern part of the instability axis, isolated thunderstorm development will be possible during the day in parts of south-central Minnesota and western Wisconsin. In this area, instability will be elevated and mid-level lapse rates will be steep, suggesting that small hail will be possible with the stronger cells. Elsewhere, isolated to scattered thunderstorms, sub-severe in nature, are expected this afternoon from parts of eastern Utah eastward into the central High Plains. ..Broyles/Wendt.. 04/13/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 PM CDT Sat Apr 12 2025 Valid 130100Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHEAST MONTANA...NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible this evening from parts of southeastern Montana and northern Wyoming into the Black Hills. ...Southeast Montana/Northern Wyoming/Far Western South Dakota... The latest water vapor imagery shows a shortwave trough over the northern Rockies, with two narrow streams of mid-level moisture associated with a mid-level jet extending northeastward from the Intermountain West into the northern High Plains. At the surface, a 1000 mb low is located in eastern Wyoming, with a cold front extending from eastern Montana southwestward into eastern Idaho. Ahead of the front, surface dewpoints are in the lower to mid 40s F from near the Wyoming-Montana state line extending northward across parts of southeast Montana. In this vicinity, the RAP has a maximum of weak instability with MLCAPE near 300 J/kg. In addition, RAP forecast soundings this evening in far southeast Montana have 60 to 70 knots of 0-6 km shear, and steep low-level lapse rates exceeding 8 C/km. This environment may support marginally severe gusts associated with cells that develop near the front as it moves eastward. The threat may affect parts of far western South Dakota later this evening. ..Broyles.. 04/13/2025 Read more

No Mesoscale Discussions are in effect as of Sat Apr 12 22:32:02 UTC 2025.

No watches are valid as of Sat Apr 12 22:32:02 UTC 2025.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0333 PM CDT Sat Apr 12 2025 Valid 141200Z - 201200Z A dry and breezy post-frontal airmass across the Central Plains, associated with an eastward moving mid-level shortwave trough, will result in some elevated fire-weather concerns on D3/Monday from southwest South Dakota/northwest Nebraska into northeastern Kansas. By D4/Tuesday, generally west-southwesterly flow will overspread the Southwestern U.S., where deep mixing will transport momentum downward into a warm, dry boundary layer. The ECMWF also indicates some potential for an embedded shortwave trough to move from Baja into the Four Corners, which could provide some enhancement to the surface winds and associated fire-weather concerns. On D5/Wednesday, a surface cyclone is forecast to develop in the lee of the Rockies beneath generally zonal mid-level flow. Deep boundary layer mixing on the west side of a dryline will result in some heightened fire-weather concerns across portions of the western Texas Panhandle into eastern New Mexico. Heading into D6/Thursday, a mid-level trough is forecast to move from the Pacific Northwest into the Great Basin, with fairly good agreement from both the ECMWF and GFS deterministic and ensemble forecasts. This will result in an intensifying 500mb height gradient across the southern Rockies, along with a deepening of the forecast surface low over the Central/Northern plains. The response in surface winds will result in widespread 20-25 MPH winds across portions of West Texas, eastern New Mexico, and southern Colorado with relative humidity values at or below 10%. Future outlooks for D6/Thursday may need an upgrade to 70% Critical pending continued forecast consistency and agreement between ensembles. While some fire-weather threat may persist into D7/Friday and D8/Saturday across the Southern Plains, predictability is too low for any highlight areas at this time. ..Halbert.. 04/12/2025 ...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 0333 PM CDT Sat Apr 12 2025 Valid 141200Z - 201200Z A dry and breezy post-frontal airmass across the Central Plains, associated with an eastward moving mid-level shortwave trough, will result in some elevated fire-weather concerns on D3/Monday from southwest South Dakota/northwest Nebraska into northeastern Kansas. By D4/Tuesday, generally west-southwesterly flow will overspread the Southwestern U.S., where deep mixing will transport momentum downward into a warm, dry boundary layer. The ECMWF also indicates some potential for an embedded shortwave trough to move from Baja into the Four Corners, which could provide some enhancement to the surface winds and associated fire-weather concerns. On D5/Wednesday, a surface cyclone is forecast to develop in the lee of the Rockies beneath generally zonal mid-level flow. Deep boundary layer mixing on the west side of a dryline will result in some heightened fire-weather concerns across portions of the western Texas Panhandle into eastern New Mexico. Heading into D6/Thursday, a mid-level trough is forecast to move from the Pacific Northwest into the Great Basin, with fairly good agreement from both the ECMWF and GFS deterministic and ensemble forecasts. This will result in an intensifying 500mb height gradient across the southern Rockies, along with a deepening of the forecast surface low over the Central/Northern plains. The response in surface winds will result in widespread 20-25 MPH winds across portions of West Texas, eastern New Mexico, and southern Colorado with relative humidity values at or below 10%. Future outlooks for D6/Thursday may need an upgrade to 70% Critical pending continued forecast consistency and agreement between ensembles. While some fire-weather threat may persist into D7/Friday and D8/Saturday across the Southern Plains, predictability is too low for any highlight areas at this time. ..Halbert.. 04/12/2025 ...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 0333 PM CDT Sat Apr 12 2025 Valid 141200Z - 201200Z A dry and breezy post-frontal airmass across the Central Plains, associated with an eastward moving mid-level shortwave trough, will result in some elevated fire-weather concerns on D3/Monday from southwest South Dakota/northwest Nebraska into northeastern Kansas. By D4/Tuesday, generally west-southwesterly flow will overspread the Southwestern U.S., where deep mixing will transport momentum downward into a warm, dry boundary layer. The ECMWF also indicates some potential for an embedded shortwave trough to move from Baja into the Four Corners, which could provide some enhancement to the surface winds and associated fire-weather concerns. On D5/Wednesday, a surface cyclone is forecast to develop in the lee of the Rockies beneath generally zonal mid-level flow. Deep boundary layer mixing on the west side of a dryline will result in some heightened fire-weather concerns across portions of the western Texas Panhandle into eastern New Mexico. Heading into D6/Thursday, a mid-level trough is forecast to move from the Pacific Northwest into the Great Basin, with fairly good agreement from both the ECMWF and GFS deterministic and ensemble forecasts. This will result in an intensifying 500mb height gradient across the southern Rockies, along with a deepening of the forecast surface low over the Central/Northern plains. The response in surface winds will result in widespread 20-25 MPH winds across portions of West Texas, eastern New Mexico, and southern Colorado with relative humidity values at or below 10%. Future outlooks for D6/Thursday may need an upgrade to 70% Critical pending continued forecast consistency and agreement between ensembles. While some fire-weather threat may persist into D7/Friday and D8/Saturday across the Southern Plains, predictability is too low for any highlight areas at this time. ..Halbert.. 04/12/2025 ...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 0333 PM CDT Sat Apr 12 2025 Valid 141200Z - 201200Z A dry and breezy post-frontal airmass across the Central Plains, associated with an eastward moving mid-level shortwave trough, will result in some elevated fire-weather concerns on D3/Monday from southwest South Dakota/northwest Nebraska into northeastern Kansas. By D4/Tuesday, generally west-southwesterly flow will overspread the Southwestern U.S., where deep mixing will transport momentum downward into a warm, dry boundary layer. The ECMWF also indicates some potential for an embedded shortwave trough to move from Baja into the Four Corners, which could provide some enhancement to the surface winds and associated fire-weather concerns. On D5/Wednesday, a surface cyclone is forecast to develop in the lee of the Rockies beneath generally zonal mid-level flow. Deep boundary layer mixing on the west side of a dryline will result in some heightened fire-weather concerns across portions of the western Texas Panhandle into eastern New Mexico. Heading into D6/Thursday, a mid-level trough is forecast to move from the Pacific Northwest into the Great Basin, with fairly good agreement from both the ECMWF and GFS deterministic and ensemble forecasts. This will result in an intensifying 500mb height gradient across the southern Rockies, along with a deepening of the forecast surface low over the Central/Northern plains. The response in surface winds will result in widespread 20-25 MPH winds across portions of West Texas, eastern New Mexico, and southern Colorado with relative humidity values at or below 10%. Future outlooks for D6/Thursday may need an upgrade to 70% Critical pending continued forecast consistency and agreement between ensembles. While some fire-weather threat may persist into D7/Friday and D8/Saturday across the Southern Plains, predictability is too low for any highlight areas at this time. ..Halbert.. 04/12/2025 ...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 0333 PM CDT Sat Apr 12 2025 Valid 141200Z - 201200Z A dry and breezy post-frontal airmass across the Central Plains, associated with an eastward moving mid-level shortwave trough, will result in some elevated fire-weather concerns on D3/Monday from southwest South Dakota/northwest Nebraska into northeastern Kansas. By D4/Tuesday, generally west-southwesterly flow will overspread the Southwestern U.S., where deep mixing will transport momentum downward into a warm, dry boundary layer. The ECMWF also indicates some potential for an embedded shortwave trough to move from Baja into the Four Corners, which could provide some enhancement to the surface winds and associated fire-weather concerns. On D5/Wednesday, a surface cyclone is forecast to develop in the lee of the Rockies beneath generally zonal mid-level flow. Deep boundary layer mixing on the west side of a dryline will result in some heightened fire-weather concerns across portions of the western Texas Panhandle into eastern New Mexico. Heading into D6/Thursday, a mid-level trough is forecast to move from the Pacific Northwest into the Great Basin, with fairly good agreement from both the ECMWF and GFS deterministic and ensemble forecasts. This will result in an intensifying 500mb height gradient across the southern Rockies, along with a deepening of the forecast surface low over the Central/Northern plains. The response in surface winds will result in widespread 20-25 MPH winds across portions of West Texas, eastern New Mexico, and southern Colorado with relative humidity values at or below 10%. Future outlooks for D6/Thursday may need an upgrade to 70% Critical pending continued forecast consistency and agreement between ensembles. While some fire-weather threat may persist into D7/Friday and D8/Saturday across the Southern Plains, predictability is too low for any highlight areas at this time. ..Halbert.. 04/12/2025 ...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 0333 PM CDT Sat Apr 12 2025 Valid 141200Z - 201200Z A dry and breezy post-frontal airmass across the Central Plains, associated with an eastward moving mid-level shortwave trough, will result in some elevated fire-weather concerns on D3/Monday from southwest South Dakota/northwest Nebraska into northeastern Kansas. By D4/Tuesday, generally west-southwesterly flow will overspread the Southwestern U.S., where deep mixing will transport momentum downward into a warm, dry boundary layer. The ECMWF also indicates some potential for an embedded shortwave trough to move from Baja into the Four Corners, which could provide some enhancement to the surface winds and associated fire-weather concerns. On D5/Wednesday, a surface cyclone is forecast to develop in the lee of the Rockies beneath generally zonal mid-level flow. Deep boundary layer mixing on the west side of a dryline will result in some heightened fire-weather concerns across portions of the western Texas Panhandle into eastern New Mexico. Heading into D6/Thursday, a mid-level trough is forecast to move from the Pacific Northwest into the Great Basin, with fairly good agreement from both the ECMWF and GFS deterministic and ensemble forecasts. This will result in an intensifying 500mb height gradient across the southern Rockies, along with a deepening of the forecast surface low over the Central/Northern plains. The response in surface winds will result in widespread 20-25 MPH winds across portions of West Texas, eastern New Mexico, and southern Colorado with relative humidity values at or below 10%. Future outlooks for D6/Thursday may need an upgrade to 70% Critical pending continued forecast consistency and agreement between ensembles. While some fire-weather threat may persist into D7/Friday and D8/Saturday across the Southern Plains, predictability is too low for any highlight areas at this time. ..Halbert.. 04/12/2025 ...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 0333 PM CDT Sat Apr 12 2025 Valid 141200Z - 201200Z A dry and breezy post-frontal airmass across the Central Plains, associated with an eastward moving mid-level shortwave trough, will result in some elevated fire-weather concerns on D3/Monday from southwest South Dakota/northwest Nebraska into northeastern Kansas. By D4/Tuesday, generally west-southwesterly flow will overspread the Southwestern U.S., where deep mixing will transport momentum downward into a warm, dry boundary layer. The ECMWF also indicates some potential for an embedded shortwave trough to move from Baja into the Four Corners, which could provide some enhancement to the surface winds and associated fire-weather concerns. On D5/Wednesday, a surface cyclone is forecast to develop in the lee of the Rockies beneath generally zonal mid-level flow. Deep boundary layer mixing on the west side of a dryline will result in some heightened fire-weather concerns across portions of the western Texas Panhandle into eastern New Mexico. Heading into D6/Thursday, a mid-level trough is forecast to move from the Pacific Northwest into the Great Basin, with fairly good agreement from both the ECMWF and GFS deterministic and ensemble forecasts. This will result in an intensifying 500mb height gradient across the southern Rockies, along with a deepening of the forecast surface low over the Central/Northern plains. The response in surface winds will result in widespread 20-25 MPH winds across portions of West Texas, eastern New Mexico, and southern Colorado with relative humidity values at or below 10%. Future outlooks for D6/Thursday may need an upgrade to 70% Critical pending continued forecast consistency and agreement between ensembles. While some fire-weather threat may persist into D7/Friday and D8/Saturday across the Southern Plains, predictability is too low for any highlight areas at this time. ..Halbert.. 04/12/2025 ...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 0237 PM CDT Sat Apr 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MONTANA INTO NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible across parts of southern Montana/northern Wyoming to the Black Hills this afternoon and evening. ...20Z Update... The forecast remains on track, and no changes were made with this update. For details, see the previous discussion below. ..Weinman.. 04/12/2025 .PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Apr 12 2025/ ...Southern Montana into Northern Wyoming and Far Western South Dakota... A mid-level shortwave trough over WA/OR will move eastward over ID/MT/WY by tonight, with downstream lee cyclogenesis occurring across the central High Plains. Low-level moisture will remain very limited across the northern Rockies and adjacent High Plains, with surface dewpoints generally in the 30s. But, forcing for ascent and mid-level moisture should be sufficient for high-based thunderstorms to develop this afternoon/evening across parts of northern WY and southern MT. Forecast soundings show inverted-v profiles with weak instability and some increase in mid-level winds, which could support isolated strong to severe wind gusts with this convection as it spreads eastward. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0237 PM CDT Sat Apr 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MONTANA INTO NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible across parts of southern Montana/northern Wyoming to the Black Hills this afternoon and evening. ...20Z Update... The forecast remains on track, and no changes were made with this update. For details, see the previous discussion below. ..Weinman.. 04/12/2025 .PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Apr 12 2025/ ...Southern Montana into Northern Wyoming and Far Western South Dakota... A mid-level shortwave trough over WA/OR will move eastward over ID/MT/WY by tonight, with downstream lee cyclogenesis occurring across the central High Plains. Low-level moisture will remain very limited across the northern Rockies and adjacent High Plains, with surface dewpoints generally in the 30s. But, forcing for ascent and mid-level moisture should be sufficient for high-based thunderstorms to develop this afternoon/evening across parts of northern WY and southern MT. Forecast soundings show inverted-v profiles with weak instability and some increase in mid-level winds, which could support isolated strong to severe wind gusts with this convection as it spreads eastward. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0237 PM CDT Sat Apr 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MONTANA INTO NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible across parts of southern Montana/northern Wyoming to the Black Hills this afternoon and evening. ...20Z Update... The forecast remains on track, and no changes were made with this update. For details, see the previous discussion below. ..Weinman.. 04/12/2025 .PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Apr 12 2025/ ...Southern Montana into Northern Wyoming and Far Western South Dakota... A mid-level shortwave trough over WA/OR will move eastward over ID/MT/WY by tonight, with downstream lee cyclogenesis occurring across the central High Plains. Low-level moisture will remain very limited across the northern Rockies and adjacent High Plains, with surface dewpoints generally in the 30s. But, forcing for ascent and mid-level moisture should be sufficient for high-based thunderstorms to develop this afternoon/evening across parts of northern WY and southern MT. Forecast soundings show inverted-v profiles with weak instability and some increase in mid-level winds, which could support isolated strong to severe wind gusts with this convection as it spreads eastward. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0237 PM CDT Sat Apr 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MONTANA INTO NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible across parts of southern Montana/northern Wyoming to the Black Hills this afternoon and evening. ...20Z Update... The forecast remains on track, and no changes were made with this update. For details, see the previous discussion below. ..Weinman.. 04/12/2025 .PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Apr 12 2025/ ...Southern Montana into Northern Wyoming and Far Western South Dakota... A mid-level shortwave trough over WA/OR will move eastward over ID/MT/WY by tonight, with downstream lee cyclogenesis occurring across the central High Plains. Low-level moisture will remain very limited across the northern Rockies and adjacent High Plains, with surface dewpoints generally in the 30s. But, forcing for ascent and mid-level moisture should be sufficient for high-based thunderstorms to develop this afternoon/evening across parts of northern WY and southern MT. Forecast soundings show inverted-v profiles with weak instability and some increase in mid-level winds, which could support isolated strong to severe wind gusts with this convection as it spreads eastward. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0237 PM CDT Sat Apr 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MONTANA INTO NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible across parts of southern Montana/northern Wyoming to the Black Hills this afternoon and evening. ...20Z Update... The forecast remains on track, and no changes were made with this update. For details, see the previous discussion below. ..Weinman.. 04/12/2025 .PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Apr 12 2025/ ...Southern Montana into Northern Wyoming and Far Western South Dakota... A mid-level shortwave trough over WA/OR will move eastward over ID/MT/WY by tonight, with downstream lee cyclogenesis occurring across the central High Plains. Low-level moisture will remain very limited across the northern Rockies and adjacent High Plains, with surface dewpoints generally in the 30s. But, forcing for ascent and mid-level moisture should be sufficient for high-based thunderstorms to develop this afternoon/evening across parts of northern WY and southern MT. Forecast soundings show inverted-v profiles with weak instability and some increase in mid-level winds, which could support isolated strong to severe wind gusts with this convection as it spreads eastward. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0237 PM CDT Sat Apr 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MONTANA INTO NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible across parts of southern Montana/northern Wyoming to the Black Hills this afternoon and evening. ...20Z Update... The forecast remains on track, and no changes were made with this update. For details, see the previous discussion below. ..Weinman.. 04/12/2025 .PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Apr 12 2025/ ...Southern Montana into Northern Wyoming and Far Western South Dakota... A mid-level shortwave trough over WA/OR will move eastward over ID/MT/WY by tonight, with downstream lee cyclogenesis occurring across the central High Plains. Low-level moisture will remain very limited across the northern Rockies and adjacent High Plains, with surface dewpoints generally in the 30s. But, forcing for ascent and mid-level moisture should be sufficient for high-based thunderstorms to develop this afternoon/evening across parts of northern WY and southern MT. Forecast soundings show inverted-v profiles with weak instability and some increase in mid-level winds, which could support isolated strong to severe wind gusts with this convection as it spreads eastward. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0237 PM CDT Sat Apr 12 2025 Valid 122000Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MONTANA INTO NORTHERN WYOMING AND FAR WESTERN SOUTH DAKOTA... ...SUMMARY... Thunderstorms with isolated severe gusts are possible across parts of southern Montana/northern Wyoming to the Black Hills this afternoon and evening. ...20Z Update... The forecast remains on track, and no changes were made with this update. For details, see the previous discussion below. ..Weinman.. 04/12/2025 .PREV DISCUSSION... /ISSUED 1112 AM CDT Sat Apr 12 2025/ ...Southern Montana into Northern Wyoming and Far Western South Dakota... A mid-level shortwave trough over WA/OR will move eastward over ID/MT/WY by tonight, with downstream lee cyclogenesis occurring across the central High Plains. Low-level moisture will remain very limited across the northern Rockies and adjacent High Plains, with surface dewpoints generally in the 30s. But, forcing for ascent and mid-level moisture should be sufficient for high-based thunderstorms to develop this afternoon/evening across parts of northern WY and southern MT. Forecast soundings show inverted-v profiles with weak instability and some increase in mid-level winds, which could support isolated strong to severe wind gusts with this convection as it spreads eastward. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Sat Apr 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NORTHERN KENTUCKY INTO SOUTHERN OHIO...SOUTHWEST PENNSYLVANIA...AND WEST VIRGINIA... ...SUMMARY... Scattered storms, a few severe, are possible on Monday afternoon and evening across parts of the Upper Ohio Valley and central Appalachians. ...Synopsis... An upper low will deepen as it moves eastward across the Great Lakes on Monday, with a leading speed max moving across the OH Valley during the day and a secondary stronger wave arriving overnight. At the surface, low pressure will deepen from Lake Superior into southwest Quebec, with a cold front extending southwestward across OH and into the OH Valley during the day. Just off the surface, 850 mb winds will be veered to westerly, with speeds increasing to around 40 kt with the cold front passage. High pressure will maintain dry conditions over much of the Southeast, but a narrow plume of mid 50s F dewpoints will develop ahead of the cold front. Midlevel moistening with the lead wave will shift east from MO across IL, IN, OH and northern KY during the day. ...Northern KY into OH, WV, PA, MD... Increasing midlevel moisture, as well as low-level moisture advection will lead to gradual destabilization, but also perhaps reduced daytime heating ahead of the cold front. Forecast soundings from several models indicate relatively poor lapse rates below 700 mb with a relative warm nose at that level. Midlevel cooling will still result in 500-1000 J/kg MUCAPE, likely elevated instability over northern areas. That said, increasing mean boundary-layer wind speeds near the front and potential for pockets of stronger instability/heating could still yield strong to severe gusts, and, marginal hail as hodographs will be long. ..Jewell.. 04/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Sat Apr 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NORTHERN KENTUCKY INTO SOUTHERN OHIO...SOUTHWEST PENNSYLVANIA...AND WEST VIRGINIA... ...SUMMARY... Scattered storms, a few severe, are possible on Monday afternoon and evening across parts of the Upper Ohio Valley and central Appalachians. ...Synopsis... An upper low will deepen as it moves eastward across the Great Lakes on Monday, with a leading speed max moving across the OH Valley during the day and a secondary stronger wave arriving overnight. At the surface, low pressure will deepen from Lake Superior into southwest Quebec, with a cold front extending southwestward across OH and into the OH Valley during the day. Just off the surface, 850 mb winds will be veered to westerly, with speeds increasing to around 40 kt with the cold front passage. High pressure will maintain dry conditions over much of the Southeast, but a narrow plume of mid 50s F dewpoints will develop ahead of the cold front. Midlevel moistening with the lead wave will shift east from MO across IL, IN, OH and northern KY during the day. ...Northern KY into OH, WV, PA, MD... Increasing midlevel moisture, as well as low-level moisture advection will lead to gradual destabilization, but also perhaps reduced daytime heating ahead of the cold front. Forecast soundings from several models indicate relatively poor lapse rates below 700 mb with a relative warm nose at that level. Midlevel cooling will still result in 500-1000 J/kg MUCAPE, likely elevated instability over northern areas. That said, increasing mean boundary-layer wind speeds near the front and potential for pockets of stronger instability/heating could still yield strong to severe gusts, and, marginal hail as hodographs will be long. ..Jewell.. 04/12/2025 Read more