Severe Storms

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Sun Jul 27 2025 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS CENTRAL/EASTERN SOUTH DAKOTA...FAR SOUTHWEST MINNESOTA...FAR NORTHWEST IOWA... ...SUMMARY... Severe thunderstorms are possible from the northern Rockies into the Dakotas and Upper Midwest Monday afternoon and evening. ...Synopsis... Strong mid-level flow will continue in the northern Plains along the crest of the upper ridge in the central CONUS. More modest mid-level winds will also extend westward into the northern Rockies and portions of the northern Great Basin. At the surface, a cold front will be positioned from northern Rockies into the northern Plains. A surface low will deepen in South Dakota/Nebraska. A theta-e boundary/pseudo warm front will extend from the low into Minnesota Wisconsin. A few subtle shortwaves are expected to move into the northern Plains as they progress along the periphery of the upper ridge. ...South Dakota into Upper Mississippi Valley... While the forecast remains complex and there are still some uncertainties to be resolved, there is sufficient confidence in storm development and coverage in parts of central/eastern South Dakota to increase severe probabilities. Strong heating to the west of the surface trough/low, the southward advancing cold front, and subtle lift from mid-level shortwave troughs suggest storm development is more probable than not. Both CAMs as well as mesoscale/global models show signals for this scenario. There is still some potential for storms to develop farther northwest in southeastern Montana and progress along the boundary into greater buoyancy, but this solution is rather uncertain. There is additional uncertainty as to how far east a greater severe threat will extend. The NAM/ECMWF/GFS and a couple of CAMs show an MCS moving through central/southern Minnesota late Sunday into Monday morning. Given the unknown amount of airmass recovery that will occur in this area, Marginal risk probabilities will remain. Strong to extreme buoyancy is expected (3000-4000+ J/kg MLCAPE) south of the cold front. With 35-50 kts of effective shear, storms will be organized. Initial development near the surface low will likely be supercellular for a period, though a couple of brief supercells could also occur along the cold front. These storms would bring the greatest risk for hail and perhaps a tornado. With some larger temperature-dewpoint spreads at the surface, along with boundary-parallel shear and eventual southward movement of the front, upscale growth will likely occur fairly quickly in the convective cycle. Potential exists for a severe MCS to develop and move along the boundary. A swath of severe gusts would be possible should this occur. ...Montana into western Dakotas... Modest surface moisture will be pushed into the northern Rockies. Storm development is likely within parts of central Montana over the terrain. With cool temperatures aloft, MLCAPE of around 1000 J/kg is possible during the afternoon. Effective shear will be near 30 kts farther west but will increase with eastward extent. A well-mixed boundary layer will promote severe wind potential, though isolated marginal hail could occur with the stronger storms. In eastern Montana, a weak surface trough intersecting with the cold front may serve as a focus for convective development during the early afternoon. Storms would likely be outflow dominant with a primary hazard of severe wind gusts. The question will be whether a more organized cluster can evolve out of this activity and progress southeastward along the boundary. Confidence is too low in this particular outcome to increase severe probabilities. ...Lower Ohio Valley into Mid-South... There is a conditional risk for marginally organized storm clusters associated with an MCV from Sunday convection in the Upper Midwest. Given the uncertain position and intensity of the MCV, highlights will be withheld at this juncture. ..Wendt.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Sun Jul 27 2025 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY AND WESTERN GREAT LAKES... ...SUMMARY... Severe thunderstorms will be possible this afternoon and evening from parts of the upper Mississippi Valley into the western Great Lakes. Marginally severe storms will also be possible in parts of the northern Plains, central Appalachians, Mid-Atlantic and eastern North Carolina. ...Upper Mississippi Valley/Western Great Lakes/Northern Plains... A shortwave mid-level trough will move eastward into the western Great Lakes today, as a ridge moves into the northern Plains. At the surface, a cold front will advance southeastward across the northern Plains, as a moist and unstable airmass remains over much of the upper Mississippi Valley. As surface temperatures warm during the day, thunderstorm development will be likely from the front in north-central Minnesota eastward to near the tip of Lake Superior. Convective coverage is forecast to expand in coverage during the late afternoon as a line segment organizes and moves eastward across the region. Ahead of the front, surface dewpoints are expected to be mostly in the 70s F. This will contribute to the development of strong instability by afternoon. RAP forecast soundings by 21Z near the instability axis have MLCAPE in the 2500 to 3500 J/kg range. In addition, 0-6 km shear is forecast to be around 30 knots, which should be sufficient for isolated supercell development. Large hail will be possible with any cell that can become locally intense. Although supercells will be possible, the most common storm mode should be multicellular. Some model forecasts suggest that a broken line segment will develop and move from central and eastern Minnesota into northern Wisconsin during the mid to late afternoon. These storms should have wind-damage potential. Additional development should occur as the low-level jet gradually ramps up, further to the southwest across parts of far eastern South Dakota and south-central Minnesota. Isolated large hail and wind damage may occur with these storms as well. Further west into parts of northern North Dakota and northern Montana, moderate instability is expected to develop in some areas by late afternoon and early evening. Isolated to scattered thunderstorms may develop across parts of this post-frontal airmass. RAP forecast soundings by late afternoon from northeast Montana into northwest North Dakota suggest that moderate deep-layer shear and steep mid-level lapse rates will be in place. This should support an isolated severe threat. However, the severe threat should be marginal, mainly due to limited large-scale ascent. ...Central Appalachians/Mid-Atlantic/Eastern North Carolina... Northwest mid-level flow will be in place today across much of the northeastern U.S., as a subtle shortwave trough moves southeastward across the region. A north-to-south axis of moisture and instability is forecast to be in place by afternoon from eastern North Carolina into the Mid-Atlantic. Isolated to scattered thunderstorms are expected to develop in the afternoon near the instability axis, and in the higher terrain of the central Appalachians. RAP forecast soundings late this afternoon near the instability axis have MLCAPE peaking around 3000 J/kg, with steep low-level lapse rates and surface dewpoints in the upper 70s F. This environment should support a marginal wind-damage threat with the stronger multicells. ..Broyles/Squitieri.. 07/27/2025 Read more