Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Sep 03 2025 Valid 031630Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND LOWER MISSOURI VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing large to very large hail and severe wind gusts should occur this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains into the Lower Missouri Valley... A mid-level shortwave trough over southern SD/eastern NE will continue to advance quickly southeastward today as a large-scale upper-level low moves from western ON to near Lake Superior through the period. The shortwave trough is forecast to reach the lower MO Valley by late afternoon, with an attendant belt of moderately strong northwesterly mid/high-level flow overspreading the central Plains into the mid MS Valley. At the surface, a cold front will advance southward across parts of the central Plains and lower MO Valley, with generally low to mid 60s surface dewpoints present ahead of the boundary. Diurnal heating of this airmass will contribute to moderate instability (MLCAPE around 1000-2000 J/kg) by mid afternoon across central/eastern KS, with weaker instability forecast with eastward extent into MO. As convective inhibition gradually erodes near the front, scattered thunderstorms will likely develop along its length from central KS into the lower MO Valley during the 20-00Z period. Around 35-55 kt of northwesterly flow in the 500-250 mb layer will yield similar values of effective bulk shear, which will support organized updrafts. A few supercells will probably evolve across central/eastern KS and perhaps into western MO, where the main risk will be large to very large hail given steep lapse rates aloft and favorable shear. Severe wind gusts will also be possible with these supercells, or any small clusters/bowing segments that can develop where low-level lapse rates are steepest (mainly KS into northwest OK and parts of the OK/TX Panhandles). Some severe threat should persist into the evening as multiple small clusters move southward into southern KS and adjacent portions of far northern OK and southwest MO, before they eventually weaken as convective inhibition increases with nocturnal cooling. ...Great Lakes/Midwest... Additional thunderstorms should develop this afternoon along/near the cold front across parts of Lower MI into central IL. Poor lapse rates aloft and limited low-level moisture (reference 12Z soundings from APX and ILX) will likely temper the degree of instability that can develop, even with diurnal heating. While occasional strong/gusty winds appear possible with thunderstorms that spread east-southeastward this afternoon and evening, the overall severe threat should remain fairly limited. ..Gleason/Lyons.. 09/03/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Sep 03 2025 Valid 031630Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND LOWER MISSOURI VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing large to very large hail and severe wind gusts should occur this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains into the Lower Missouri Valley... A mid-level shortwave trough over southern SD/eastern NE will continue to advance quickly southeastward today as a large-scale upper-level low moves from western ON to near Lake Superior through the period. The shortwave trough is forecast to reach the lower MO Valley by late afternoon, with an attendant belt of moderately strong northwesterly mid/high-level flow overspreading the central Plains into the mid MS Valley. At the surface, a cold front will advance southward across parts of the central Plains and lower MO Valley, with generally low to mid 60s surface dewpoints present ahead of the boundary. Diurnal heating of this airmass will contribute to moderate instability (MLCAPE around 1000-2000 J/kg) by mid afternoon across central/eastern KS, with weaker instability forecast with eastward extent into MO. As convective inhibition gradually erodes near the front, scattered thunderstorms will likely develop along its length from central KS into the lower MO Valley during the 20-00Z period. Around 35-55 kt of northwesterly flow in the 500-250 mb layer will yield similar values of effective bulk shear, which will support organized updrafts. A few supercells will probably evolve across central/eastern KS and perhaps into western MO, where the main risk will be large to very large hail given steep lapse rates aloft and favorable shear. Severe wind gusts will also be possible with these supercells, or any small clusters/bowing segments that can develop where low-level lapse rates are steepest (mainly KS into northwest OK and parts of the OK/TX Panhandles). Some severe threat should persist into the evening as multiple small clusters move southward into southern KS and adjacent portions of far northern OK and southwest MO, before they eventually weaken as convective inhibition increases with nocturnal cooling. ...Great Lakes/Midwest... Additional thunderstorms should develop this afternoon along/near the cold front across parts of Lower MI into central IL. Poor lapse rates aloft and limited low-level moisture (reference 12Z soundings from APX and ILX) will likely temper the degree of instability that can develop, even with diurnal heating. While occasional strong/gusty winds appear possible with thunderstorms that spread east-southeastward this afternoon and evening, the overall severe threat should remain fairly limited. ..Gleason/Lyons.. 09/03/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Sep 03 2025 Valid 031630Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND LOWER MISSOURI VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing large to very large hail and severe wind gusts should occur this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains into the Lower Missouri Valley... A mid-level shortwave trough over southern SD/eastern NE will continue to advance quickly southeastward today as a large-scale upper-level low moves from western ON to near Lake Superior through the period. The shortwave trough is forecast to reach the lower MO Valley by late afternoon, with an attendant belt of moderately strong northwesterly mid/high-level flow overspreading the central Plains into the mid MS Valley. At the surface, a cold front will advance southward across parts of the central Plains and lower MO Valley, with generally low to mid 60s surface dewpoints present ahead of the boundary. Diurnal heating of this airmass will contribute to moderate instability (MLCAPE around 1000-2000 J/kg) by mid afternoon across central/eastern KS, with weaker instability forecast with eastward extent into MO. As convective inhibition gradually erodes near the front, scattered thunderstorms will likely develop along its length from central KS into the lower MO Valley during the 20-00Z period. Around 35-55 kt of northwesterly flow in the 500-250 mb layer will yield similar values of effective bulk shear, which will support organized updrafts. A few supercells will probably evolve across central/eastern KS and perhaps into western MO, where the main risk will be large to very large hail given steep lapse rates aloft and favorable shear. Severe wind gusts will also be possible with these supercells, or any small clusters/bowing segments that can develop where low-level lapse rates are steepest (mainly KS into northwest OK and parts of the OK/TX Panhandles). Some severe threat should persist into the evening as multiple small clusters move southward into southern KS and adjacent portions of far northern OK and southwest MO, before they eventually weaken as convective inhibition increases with nocturnal cooling. ...Great Lakes/Midwest... Additional thunderstorms should develop this afternoon along/near the cold front across parts of Lower MI into central IL. Poor lapse rates aloft and limited low-level moisture (reference 12Z soundings from APX and ILX) will likely temper the degree of instability that can develop, even with diurnal heating. While occasional strong/gusty winds appear possible with thunderstorms that spread east-southeastward this afternoon and evening, the overall severe threat should remain fairly limited. ..Gleason/Lyons.. 09/03/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Sep 03 2025 Valid 031630Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND LOWER MISSOURI VALLEY... ...SUMMARY... Scattered thunderstorms capable of producing large to very large hail and severe wind gusts should occur this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains into the Lower Missouri Valley... A mid-level shortwave trough over southern SD/eastern NE will continue to advance quickly southeastward today as a large-scale upper-level low moves from western ON to near Lake Superior through the period. The shortwave trough is forecast to reach the lower MO Valley by late afternoon, with an attendant belt of moderately strong northwesterly mid/high-level flow overspreading the central Plains into the mid MS Valley. At the surface, a cold front will advance southward across parts of the central Plains and lower MO Valley, with generally low to mid 60s surface dewpoints present ahead of the boundary. Diurnal heating of this airmass will contribute to moderate instability (MLCAPE around 1000-2000 J/kg) by mid afternoon across central/eastern KS, with weaker instability forecast with eastward extent into MO. As convective inhibition gradually erodes near the front, scattered thunderstorms will likely develop along its length from central KS into the lower MO Valley during the 20-00Z period. Around 35-55 kt of northwesterly flow in the 500-250 mb layer will yield similar values of effective bulk shear, which will support organized updrafts. A few supercells will probably evolve across central/eastern KS and perhaps into western MO, where the main risk will be large to very large hail given steep lapse rates aloft and favorable shear. Severe wind gusts will also be possible with these supercells, or any small clusters/bowing segments that can develop where low-level lapse rates are steepest (mainly KS into northwest OK and parts of the OK/TX Panhandles). Some severe threat should persist into the evening as multiple small clusters move southward into southern KS and adjacent portions of far northern OK and southwest MO, before they eventually weaken as convective inhibition increases with nocturnal cooling. ...Great Lakes/Midwest... Additional thunderstorms should develop this afternoon along/near the cold front across parts of Lower MI into central IL. Poor lapse rates aloft and limited low-level moisture (reference 12Z soundings from APX and ILX) will likely temper the degree of instability that can develop, even with diurnal heating. While occasional strong/gusty winds appear possible with thunderstorms that spread east-southeastward this afternoon and evening, the overall severe threat should remain fairly limited. ..Gleason/Lyons.. 09/03/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0657 AM CDT Wed Sep 03 2025 Valid 031300Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL KANSAS INTO WESTERN MISSOURI... ...SUMMARY... Scattered thunderstorms with potential for large to very large hail and severe wind gusts are expected this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains/Lower Missouri Valley... Water-vapor imagery this morning shows a mid-level shortwave trough over southern SD moving quickly southeast as a larger-scale mid- to upper-level low moves from western ON to near Lake Superior during the period. The smaller-scale disturbance is forecast to reach the lower MO Valley by late afternoon with an attendant belt of moderately strong northwesterly mid- to high-level flow overspreading the central Plains into the mid MS Valley. In the low levels, a cold front will advance southward across the central Plains and lower Missouri Valley with 60s deg F surface dewpoints ahead of the boundary. Diurnal heating will contribute to moderate buoyancy by mid afternoon with convective inhibition eroding near the front. Scattered thunderstorms are forecast to develop from central KS eastward into the lower MO Valley during the 20-00 UTC period. The aforementioned strong northwesterly flow in the 500 to 300 mb layer (35-55 kt) will yield effective shear supporting organized updrafts. A few supercells will probably evolve across KS and perhaps into western MO where the main risk will be large to very large hail. Severe wind gusts will also be possible with supercells, or small clusters/bowing segments where 0-2 km lapse rates are steepest (i.e., KS). The severe threat is expected to persist into the mid evening as several small clusters move southeastward into southeast Kansas and adjacent portions of northern OK and southwest Missouri. ..Smith/Bentley.. 09/03/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0657 AM CDT Wed Sep 03 2025 Valid 031300Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL KANSAS INTO WESTERN MISSOURI... ...SUMMARY... Scattered thunderstorms with potential for large to very large hail and severe wind gusts are expected this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains/Lower Missouri Valley... Water-vapor imagery this morning shows a mid-level shortwave trough over southern SD moving quickly southeast as a larger-scale mid- to upper-level low moves from western ON to near Lake Superior during the period. The smaller-scale disturbance is forecast to reach the lower MO Valley by late afternoon with an attendant belt of moderately strong northwesterly mid- to high-level flow overspreading the central Plains into the mid MS Valley. In the low levels, a cold front will advance southward across the central Plains and lower Missouri Valley with 60s deg F surface dewpoints ahead of the boundary. Diurnal heating will contribute to moderate buoyancy by mid afternoon with convective inhibition eroding near the front. Scattered thunderstorms are forecast to develop from central KS eastward into the lower MO Valley during the 20-00 UTC period. The aforementioned strong northwesterly flow in the 500 to 300 mb layer (35-55 kt) will yield effective shear supporting organized updrafts. A few supercells will probably evolve across KS and perhaps into western MO where the main risk will be large to very large hail. Severe wind gusts will also be possible with supercells, or small clusters/bowing segments where 0-2 km lapse rates are steepest (i.e., KS). The severe threat is expected to persist into the mid evening as several small clusters move southeastward into southeast Kansas and adjacent portions of northern OK and southwest Missouri. ..Smith/Bentley.. 09/03/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0657 AM CDT Wed Sep 03 2025 Valid 031300Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL KANSAS INTO WESTERN MISSOURI... ...SUMMARY... Scattered thunderstorms with potential for large to very large hail and severe wind gusts are expected this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains/Lower Missouri Valley... Water-vapor imagery this morning shows a mid-level shortwave trough over southern SD moving quickly southeast as a larger-scale mid- to upper-level low moves from western ON to near Lake Superior during the period. The smaller-scale disturbance is forecast to reach the lower MO Valley by late afternoon with an attendant belt of moderately strong northwesterly mid- to high-level flow overspreading the central Plains into the mid MS Valley. In the low levels, a cold front will advance southward across the central Plains and lower Missouri Valley with 60s deg F surface dewpoints ahead of the boundary. Diurnal heating will contribute to moderate buoyancy by mid afternoon with convective inhibition eroding near the front. Scattered thunderstorms are forecast to develop from central KS eastward into the lower MO Valley during the 20-00 UTC period. The aforementioned strong northwesterly flow in the 500 to 300 mb layer (35-55 kt) will yield effective shear supporting organized updrafts. A few supercells will probably evolve across KS and perhaps into western MO where the main risk will be large to very large hail. Severe wind gusts will also be possible with supercells, or small clusters/bowing segments where 0-2 km lapse rates are steepest (i.e., KS). The severe threat is expected to persist into the mid evening as several small clusters move southeastward into southeast Kansas and adjacent portions of northern OK and southwest Missouri. ..Smith/Bentley.. 09/03/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0657 AM CDT Wed Sep 03 2025 Valid 031300Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL KANSAS INTO WESTERN MISSOURI... ...SUMMARY... Scattered thunderstorms with potential for large to very large hail and severe wind gusts are expected this afternoon and evening across parts of the central Plains and lower Missouri Valley. ...Central Plains/Lower Missouri Valley... Water-vapor imagery this morning shows a mid-level shortwave trough over southern SD moving quickly southeast as a larger-scale mid- to upper-level low moves from western ON to near Lake Superior during the period. The smaller-scale disturbance is forecast to reach the lower MO Valley by late afternoon with an attendant belt of moderately strong northwesterly mid- to high-level flow overspreading the central Plains into the mid MS Valley. In the low levels, a cold front will advance southward across the central Plains and lower Missouri Valley with 60s deg F surface dewpoints ahead of the boundary. Diurnal heating will contribute to moderate buoyancy by mid afternoon with convective inhibition eroding near the front. Scattered thunderstorms are forecast to develop from central KS eastward into the lower MO Valley during the 20-00 UTC period. The aforementioned strong northwesterly flow in the 500 to 300 mb layer (35-55 kt) will yield effective shear supporting organized updrafts. A few supercells will probably evolve across KS and perhaps into western MO where the main risk will be large to very large hail. Severe wind gusts will also be possible with supercells, or small clusters/bowing segments where 0-2 km lapse rates are steepest (i.e., KS). The severe threat is expected to persist into the mid evening as several small clusters move southeastward into southeast Kansas and adjacent portions of northern OK and southwest Missouri. ..Smith/Bentley.. 09/03/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CDT Wed Sep 03 2025 Valid 061200Z - 111200Z ...DISCUSSION... The western North American midlevel ridge of the previous days will slowly move east into the central continent by the end of the forecast period and in its place an amplified longwave trough will take hold across the western US. ... Saturday/Day-4 ... Before this transition happens, a seasonably strong cold front will push east into the Atlantic and south into the northern Gulf states as an expansive surface high will move into the central US on Saturday/Day-4. Guidance disagrees to the degree instability will materialize along and ahead of the front from the Mid-Atlantic region into New England. However, pattern recognition would support scattered strong thunderstorms along the front across this region. Midlevel flow will be sufficiently strong to support at least some damaging wind potential should thunderstorms develop. ... Sunday/Day-5 through Wednesday/Day-8 ... A seasonably cool, dry continental airmass will be in place across much of the eastern two-thirds of the contiguous US, resulting in low potential of organized severe thunderstorms on Sunday/Day-5. That said, as the western trough takes hold, lee troughing will develop across the High Plains. This will result in return flow drawing low-level northward by early next week. Weak shortwave troughs/vorticity maxima embedded in the increasingly southwesterly flow may yield thunderstorms across the High Plains during the late afternoon into the overnight hours. Depending on the quality of the resulting low-level moisture return and the strength of any of these shortwave troughs, the potential for organized severe thunderstorms may develop, especially later in the forecast period. However, predictability of these features at this time scale is too low to warrant unconditional probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CDT Wed Sep 03 2025 Valid 061200Z - 111200Z ...DISCUSSION... The western North American midlevel ridge of the previous days will slowly move east into the central continent by the end of the forecast period and in its place an amplified longwave trough will take hold across the western US. ... Saturday/Day-4 ... Before this transition happens, a seasonably strong cold front will push east into the Atlantic and south into the northern Gulf states as an expansive surface high will move into the central US on Saturday/Day-4. Guidance disagrees to the degree instability will materialize along and ahead of the front from the Mid-Atlantic region into New England. However, pattern recognition would support scattered strong thunderstorms along the front across this region. Midlevel flow will be sufficiently strong to support at least some damaging wind potential should thunderstorms develop. ... Sunday/Day-5 through Wednesday/Day-8 ... A seasonably cool, dry continental airmass will be in place across much of the eastern two-thirds of the contiguous US, resulting in low potential of organized severe thunderstorms on Sunday/Day-5. That said, as the western trough takes hold, lee troughing will develop across the High Plains. This will result in return flow drawing low-level northward by early next week. Weak shortwave troughs/vorticity maxima embedded in the increasingly southwesterly flow may yield thunderstorms across the High Plains during the late afternoon into the overnight hours. Depending on the quality of the resulting low-level moisture return and the strength of any of these shortwave troughs, the potential for organized severe thunderstorms may develop, especially later in the forecast period. However, predictability of these features at this time scale is too low to warrant unconditional probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CDT Wed Sep 03 2025 Valid 061200Z - 111200Z ...DISCUSSION... The western North American midlevel ridge of the previous days will slowly move east into the central continent by the end of the forecast period and in its place an amplified longwave trough will take hold across the western US. ... Saturday/Day-4 ... Before this transition happens, a seasonably strong cold front will push east into the Atlantic and south into the northern Gulf states as an expansive surface high will move into the central US on Saturday/Day-4. Guidance disagrees to the degree instability will materialize along and ahead of the front from the Mid-Atlantic region into New England. However, pattern recognition would support scattered strong thunderstorms along the front across this region. Midlevel flow will be sufficiently strong to support at least some damaging wind potential should thunderstorms develop. ... Sunday/Day-5 through Wednesday/Day-8 ... A seasonably cool, dry continental airmass will be in place across much of the eastern two-thirds of the contiguous US, resulting in low potential of organized severe thunderstorms on Sunday/Day-5. That said, as the western trough takes hold, lee troughing will develop across the High Plains. This will result in return flow drawing low-level northward by early next week. Weak shortwave troughs/vorticity maxima embedded in the increasingly southwesterly flow may yield thunderstorms across the High Plains during the late afternoon into the overnight hours. Depending on the quality of the resulting low-level moisture return and the strength of any of these shortwave troughs, the potential for organized severe thunderstorms may develop, especially later in the forecast period. However, predictability of these features at this time scale is too low to warrant unconditional probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CDT Wed Sep 03 2025 Valid 061200Z - 111200Z ...DISCUSSION... The western North American midlevel ridge of the previous days will slowly move east into the central continent by the end of the forecast period and in its place an amplified longwave trough will take hold across the western US. ... Saturday/Day-4 ... Before this transition happens, a seasonably strong cold front will push east into the Atlantic and south into the northern Gulf states as an expansive surface high will move into the central US on Saturday/Day-4. Guidance disagrees to the degree instability will materialize along and ahead of the front from the Mid-Atlantic region into New England. However, pattern recognition would support scattered strong thunderstorms along the front across this region. Midlevel flow will be sufficiently strong to support at least some damaging wind potential should thunderstorms develop. ... Sunday/Day-5 through Wednesday/Day-8 ... A seasonably cool, dry continental airmass will be in place across much of the eastern two-thirds of the contiguous US, resulting in low potential of organized severe thunderstorms on Sunday/Day-5. That said, as the western trough takes hold, lee troughing will develop across the High Plains. This will result in return flow drawing low-level northward by early next week. Weak shortwave troughs/vorticity maxima embedded in the increasingly southwesterly flow may yield thunderstorms across the High Plains during the late afternoon into the overnight hours. Depending on the quality of the resulting low-level moisture return and the strength of any of these shortwave troughs, the potential for organized severe thunderstorms may develop, especially later in the forecast period. However, predictability of these features at this time scale is too low to warrant unconditional probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CDT Wed Sep 03 2025 Valid 061200Z - 111200Z ...DISCUSSION... The western North American midlevel ridge of the previous days will slowly move east into the central continent by the end of the forecast period and in its place an amplified longwave trough will take hold across the western US. ... Saturday/Day-4 ... Before this transition happens, a seasonably strong cold front will push east into the Atlantic and south into the northern Gulf states as an expansive surface high will move into the central US on Saturday/Day-4. Guidance disagrees to the degree instability will materialize along and ahead of the front from the Mid-Atlantic region into New England. However, pattern recognition would support scattered strong thunderstorms along the front across this region. Midlevel flow will be sufficiently strong to support at least some damaging wind potential should thunderstorms develop. ... Sunday/Day-5 through Wednesday/Day-8 ... A seasonably cool, dry continental airmass will be in place across much of the eastern two-thirds of the contiguous US, resulting in low potential of organized severe thunderstorms on Sunday/Day-5. That said, as the western trough takes hold, lee troughing will develop across the High Plains. This will result in return flow drawing low-level northward by early next week. Weak shortwave troughs/vorticity maxima embedded in the increasingly southwesterly flow may yield thunderstorms across the High Plains during the late afternoon into the overnight hours. Depending on the quality of the resulting low-level moisture return and the strength of any of these shortwave troughs, the potential for organized severe thunderstorms may develop, especially later in the forecast period. However, predictability of these features at this time scale is too low to warrant unconditional probabilities at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CDT Wed Sep 03 2025 Valid 061200Z - 111200Z ...DISCUSSION... The western North American midlevel ridge of the previous days will slowly move east into the central continent by the end of the forecast period and in its place an amplified longwave trough will take hold across the western US. ... Saturday/Day-4 ... Before this transition happens, a seasonably strong cold front will push east into the Atlantic and south into the northern Gulf states as an expansive surface high will move into the central US on Saturday/Day-4. Guidance disagrees to the degree instability will materialize along and ahead of the front from the Mid-Atlantic region into New England. However, pattern recognition would support scattered strong thunderstorms along the front across this region. Midlevel flow will be sufficiently strong to support at least some damaging wind potential should thunderstorms develop. ... Sunday/Day-5 through Wednesday/Day-8 ... A seasonably cool, dry continental airmass will be in place across much of the eastern two-thirds of the contiguous US, resulting in low potential of organized severe thunderstorms on Sunday/Day-5. That said, as the western trough takes hold, lee troughing will develop across the High Plains. This will result in return flow drawing low-level northward by early next week. Weak shortwave troughs/vorticity maxima embedded in the increasingly southwesterly flow may yield thunderstorms across the High Plains during the late afternoon into the overnight hours. Depending on the quality of the resulting low-level moisture return and the strength of any of these shortwave troughs, the potential for organized severe thunderstorms may develop, especially later in the forecast period. However, predictability of these features at this time scale is too low to warrant unconditional probabilities at this time. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Sep 03 2025 Valid 051200Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible across much of the West, the southern Rockies, Florida, and along and near a frontal boundary from New England into the southern Plains. Widespread organized severe weather is not anticipated. ... Discussion ... The amplified midlevel pattern of the previous few days will persist through Friday/Day-3 across North America, with a western Canada ridge and a continental-scale trough across eastern Canada and the eastern US. Within the eastern trough, a seasonably strong closed low over Ontario should begin to fill by late in the forecast period. As this is occurring, multiple shortwave troughs traversing the larger scale flow field will rotate around the Ontario low. The strongest of these shortwave troughs will have moved south through Canada the day before and should be located in the vicinity of the Lower Great Lakes at the start of the forecast period. In response to this shortwave trough, strong northerly low-to-mid-level flow across the Plains overnight Thursday into Friday will help tighten the low-level thermal gradient across the Plains. This front will slowly move south through Friday into Friday night. A modest surface low is expected to develop across southwest Oklahoma or northwest Texas, along the surface front, by Friday morning. This surface low should slowly sag south through the day with the front. Despite moving south, away from Oklahoma, the flow around this surface low will still be able to draw Gulf moisture northward into Oklahoma and Arkansas. As this increasing low-level moisture converges along the front, diurnal heating of this moistening airmass will yield most-unstable CAPE values perhaps in excess of 3000 J/kg along and south of the surface front. Despite the strong instability and strong thermal gradient, the slow moving nature of the front will tend to favor anafrontal circulations. This appears to be borne out in the latest operational guidance suite with precipitation being favored on the cold side of the thermal gradient. This would tend to limit the overall risk of severe weather. However, given the degree of instability and the presence of a strong cold front, the risk of warm-sector convection remains. If confidence in warm-sector convection occurring increases, severe probabilities may be warranted across portions of eastern Oklahoma east through Arkansas into western Tennessee and northern Mississippi. ..Marsh.. 09/03/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Sep 03 2025 Valid 051200Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible across much of the West, the southern Rockies, Florida, and along and near a frontal boundary from New England into the southern Plains. Widespread organized severe weather is not anticipated. ... Discussion ... The amplified midlevel pattern of the previous few days will persist through Friday/Day-3 across North America, with a western Canada ridge and a continental-scale trough across eastern Canada and the eastern US. Within the eastern trough, a seasonably strong closed low over Ontario should begin to fill by late in the forecast period. As this is occurring, multiple shortwave troughs traversing the larger scale flow field will rotate around the Ontario low. The strongest of these shortwave troughs will have moved south through Canada the day before and should be located in the vicinity of the Lower Great Lakes at the start of the forecast period. In response to this shortwave trough, strong northerly low-to-mid-level flow across the Plains overnight Thursday into Friday will help tighten the low-level thermal gradient across the Plains. This front will slowly move south through Friday into Friday night. A modest surface low is expected to develop across southwest Oklahoma or northwest Texas, along the surface front, by Friday morning. This surface low should slowly sag south through the day with the front. Despite moving south, away from Oklahoma, the flow around this surface low will still be able to draw Gulf moisture northward into Oklahoma and Arkansas. As this increasing low-level moisture converges along the front, diurnal heating of this moistening airmass will yield most-unstable CAPE values perhaps in excess of 3000 J/kg along and south of the surface front. Despite the strong instability and strong thermal gradient, the slow moving nature of the front will tend to favor anafrontal circulations. This appears to be borne out in the latest operational guidance suite with precipitation being favored on the cold side of the thermal gradient. This would tend to limit the overall risk of severe weather. However, given the degree of instability and the presence of a strong cold front, the risk of warm-sector convection remains. If confidence in warm-sector convection occurring increases, severe probabilities may be warranted across portions of eastern Oklahoma east through Arkansas into western Tennessee and northern Mississippi. ..Marsh.. 09/03/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Sep 03 2025 Valid 051200Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible across much of the West, the southern Rockies, Florida, and along and near a frontal boundary from New England into the southern Plains. Widespread organized severe weather is not anticipated. ... Discussion ... The amplified midlevel pattern of the previous few days will persist through Friday/Day-3 across North America, with a western Canada ridge and a continental-scale trough across eastern Canada and the eastern US. Within the eastern trough, a seasonably strong closed low over Ontario should begin to fill by late in the forecast period. As this is occurring, multiple shortwave troughs traversing the larger scale flow field will rotate around the Ontario low. The strongest of these shortwave troughs will have moved south through Canada the day before and should be located in the vicinity of the Lower Great Lakes at the start of the forecast period. In response to this shortwave trough, strong northerly low-to-mid-level flow across the Plains overnight Thursday into Friday will help tighten the low-level thermal gradient across the Plains. This front will slowly move south through Friday into Friday night. A modest surface low is expected to develop across southwest Oklahoma or northwest Texas, along the surface front, by Friday morning. This surface low should slowly sag south through the day with the front. Despite moving south, away from Oklahoma, the flow around this surface low will still be able to draw Gulf moisture northward into Oklahoma and Arkansas. As this increasing low-level moisture converges along the front, diurnal heating of this moistening airmass will yield most-unstable CAPE values perhaps in excess of 3000 J/kg along and south of the surface front. Despite the strong instability and strong thermal gradient, the slow moving nature of the front will tend to favor anafrontal circulations. This appears to be borne out in the latest operational guidance suite with precipitation being favored on the cold side of the thermal gradient. This would tend to limit the overall risk of severe weather. However, given the degree of instability and the presence of a strong cold front, the risk of warm-sector convection remains. If confidence in warm-sector convection occurring increases, severe probabilities may be warranted across portions of eastern Oklahoma east through Arkansas into western Tennessee and northern Mississippi. ..Marsh.. 09/03/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Sep 03 2025 Valid 051200Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible across much of the West, the southern Rockies, Florida, and along and near a frontal boundary from New England into the southern Plains. Widespread organized severe weather is not anticipated. ... Discussion ... The amplified midlevel pattern of the previous few days will persist through Friday/Day-3 across North America, with a western Canada ridge and a continental-scale trough across eastern Canada and the eastern US. Within the eastern trough, a seasonably strong closed low over Ontario should begin to fill by late in the forecast period. As this is occurring, multiple shortwave troughs traversing the larger scale flow field will rotate around the Ontario low. The strongest of these shortwave troughs will have moved south through Canada the day before and should be located in the vicinity of the Lower Great Lakes at the start of the forecast period. In response to this shortwave trough, strong northerly low-to-mid-level flow across the Plains overnight Thursday into Friday will help tighten the low-level thermal gradient across the Plains. This front will slowly move south through Friday into Friday night. A modest surface low is expected to develop across southwest Oklahoma or northwest Texas, along the surface front, by Friday morning. This surface low should slowly sag south through the day with the front. Despite moving south, away from Oklahoma, the flow around this surface low will still be able to draw Gulf moisture northward into Oklahoma and Arkansas. As this increasing low-level moisture converges along the front, diurnal heating of this moistening airmass will yield most-unstable CAPE values perhaps in excess of 3000 J/kg along and south of the surface front. Despite the strong instability and strong thermal gradient, the slow moving nature of the front will tend to favor anafrontal circulations. This appears to be borne out in the latest operational guidance suite with precipitation being favored on the cold side of the thermal gradient. This would tend to limit the overall risk of severe weather. However, given the degree of instability and the presence of a strong cold front, the risk of warm-sector convection remains. If confidence in warm-sector convection occurring increases, severe probabilities may be warranted across portions of eastern Oklahoma east through Arkansas into western Tennessee and northern Mississippi. ..Marsh.. 09/03/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Sep 03 2025 Valid 051200Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible across much of the West, the southern Rockies, Florida, and along and near a frontal boundary from New England into the southern Plains. Widespread organized severe weather is not anticipated. ... Discussion ... The amplified midlevel pattern of the previous few days will persist through Friday/Day-3 across North America, with a western Canada ridge and a continental-scale trough across eastern Canada and the eastern US. Within the eastern trough, a seasonably strong closed low over Ontario should begin to fill by late in the forecast period. As this is occurring, multiple shortwave troughs traversing the larger scale flow field will rotate around the Ontario low. The strongest of these shortwave troughs will have moved south through Canada the day before and should be located in the vicinity of the Lower Great Lakes at the start of the forecast period. In response to this shortwave trough, strong northerly low-to-mid-level flow across the Plains overnight Thursday into Friday will help tighten the low-level thermal gradient across the Plains. This front will slowly move south through Friday into Friday night. A modest surface low is expected to develop across southwest Oklahoma or northwest Texas, along the surface front, by Friday morning. This surface low should slowly sag south through the day with the front. Despite moving south, away from Oklahoma, the flow around this surface low will still be able to draw Gulf moisture northward into Oklahoma and Arkansas. As this increasing low-level moisture converges along the front, diurnal heating of this moistening airmass will yield most-unstable CAPE values perhaps in excess of 3000 J/kg along and south of the surface front. Despite the strong instability and strong thermal gradient, the slow moving nature of the front will tend to favor anafrontal circulations. This appears to be borne out in the latest operational guidance suite with precipitation being favored on the cold side of the thermal gradient. This would tend to limit the overall risk of severe weather. However, given the degree of instability and the presence of a strong cold front, the risk of warm-sector convection remains. If confidence in warm-sector convection occurring increases, severe probabilities may be warranted across portions of eastern Oklahoma east through Arkansas into western Tennessee and northern Mississippi. ..Marsh.. 09/03/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Sep 03 2025 Valid 051200Z - 061200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible across much of the West, the southern Rockies, Florida, and along and near a frontal boundary from New England into the southern Plains. Widespread organized severe weather is not anticipated. ... Discussion ... The amplified midlevel pattern of the previous few days will persist through Friday/Day-3 across North America, with a western Canada ridge and a continental-scale trough across eastern Canada and the eastern US. Within the eastern trough, a seasonably strong closed low over Ontario should begin to fill by late in the forecast period. As this is occurring, multiple shortwave troughs traversing the larger scale flow field will rotate around the Ontario low. The strongest of these shortwave troughs will have moved south through Canada the day before and should be located in the vicinity of the Lower Great Lakes at the start of the forecast period. In response to this shortwave trough, strong northerly low-to-mid-level flow across the Plains overnight Thursday into Friday will help tighten the low-level thermal gradient across the Plains. This front will slowly move south through Friday into Friday night. A modest surface low is expected to develop across southwest Oklahoma or northwest Texas, along the surface front, by Friday morning. This surface low should slowly sag south through the day with the front. Despite moving south, away from Oklahoma, the flow around this surface low will still be able to draw Gulf moisture northward into Oklahoma and Arkansas. As this increasing low-level moisture converges along the front, diurnal heating of this moistening airmass will yield most-unstable CAPE values perhaps in excess of 3000 J/kg along and south of the surface front. Despite the strong instability and strong thermal gradient, the slow moving nature of the front will tend to favor anafrontal circulations. This appears to be borne out in the latest operational guidance suite with precipitation being favored on the cold side of the thermal gradient. This would tend to limit the overall risk of severe weather. However, given the degree of instability and the presence of a strong cold front, the risk of warm-sector convection remains. If confidence in warm-sector convection occurring increases, severe probabilities may be warranted across portions of eastern Oklahoma east through Arkansas into western Tennessee and northern Mississippi. ..Marsh.. 09/03/2025 Read more