Severe Storms

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Thu Sep 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... Model guidance is in fairly good agreement that the upper trough over the central US will continue to lift northeastward into the northern Plains and Upper Midwest through early next week. This will drag a surface low and cold front slowly eastward with seasonably high moisture in place. The low will begin to fill as it also lifts into southern Canada. Scattered to numerous thunderstorms appear likely over the Northern Plains and Upper Midwest, and along the trailing front over the southern/central Plains each afternoon, as increasingly meridional flow will parallel the slow moving cold front. This will favor continued storm development/training along the boundary with limited air mass destabilization/recovery. Mid-level lapse rates should also weaken as the upper trough begins to fill. While some marginal severe risk is evident over the northern Plains near the low and front, mainly D4/Sunday, significant uncertainty exists regarding boundary-layer destabilization and its impacts on severe potential through D5/Monday. By D6/Tuesday, mid-level ridging behind the trough is forecast to temporarily strengthen, weakening upper-level flow across the CONUS. A second upper trough over the northern Rockies will begin to approach behind the central US ridge, while a cutoff low develops over the Southeast. This should limit broader overlap of instability and stronger mid-level flow across much of the CONUS. Widespread severe weather appears unlikely through next week. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0118 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... ...Synopsis... The western trough will broaden and the mid-level jet will lose definition on Friday. Though not overly intense, a surface low will move into the central Plains and help promote windier conditions for parts of the central/southern Plains. Recent rainfall and generally unreceptive fuels will mean very minimal fire risk. Dry conditions will persist in parts of the Great Basin and Southwest, but winds will be weaker than previous days. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0118 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... ...Synopsis... The western trough will broaden and the mid-level jet will lose definition on Friday. Though not overly intense, a surface low will move into the central Plains and help promote windier conditions for parts of the central/southern Plains. Recent rainfall and generally unreceptive fuels will mean very minimal fire risk. Dry conditions will persist in parts of the Great Basin and Southwest, but winds will be weaker than previous days. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0118 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... ...Synopsis... The western trough will broaden and the mid-level jet will lose definition on Friday. Though not overly intense, a surface low will move into the central Plains and help promote windier conditions for parts of the central/southern Plains. Recent rainfall and generally unreceptive fuels will mean very minimal fire risk. Dry conditions will persist in parts of the Great Basin and Southwest, but winds will be weaker than previous days. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0118 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... ...Synopsis... The western trough will broaden and the mid-level jet will lose definition on Friday. Though not overly intense, a surface low will move into the central Plains and help promote windier conditions for parts of the central/southern Plains. Recent rainfall and generally unreceptive fuels will mean very minimal fire risk. Dry conditions will persist in parts of the Great Basin and Southwest, but winds will be weaker than previous days. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0117 AM CDT Thu Sep 11 2025 Valid 111200Z - 121200Z ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0117 AM CDT Thu Sep 11 2025 Valid 111200Z - 121200Z ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0117 AM CDT Thu Sep 11 2025 Valid 111200Z - 121200Z ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0117 AM CDT Thu Sep 11 2025 Valid 111200Z - 121200Z ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ..Wendt.. 09/11/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE FOUR CORNERS... ...SUMMARY... Strong to severe storms capable of isolated severe wind gusts are possible across the Four Corners region on Friday. Additional storms are possible over the northern Plains and Upper Midwest Friday. ...Northern Plains and Upper Midwest... A shortwave trough and enhanced southwesterly flow will move out of the northern Rockies and into the northern Plains Friday as upper ridging begins to move eastward. Associated with the approaching trough, a weak lee cyclone along a stalled front over the Dakotas will draw rich low-level moisture westward toward a second weak cold front moving out of the Rockies. Modest ascent is expected much of the day along and north of the surface low/front across northern WY, western ND and central/eastern MT. While cloud cover and early morning convection may temper heating somewhat, elevated buoyancy is expected to support scattered to numerous storms through the afternoon. With 35-45 kt of southwesterly flow aloft extending mid and upper-level hodographs, a few elevated clusters or supercells are possible. Steep mid-level lapse rates and favorable deep-layer shear could support isolated hail and strong gusts with the strongest storms, though confidence in the overall severe risk remains fairly low given the potential for clouds and early morning storms. Convective coverage may increase through the evening and overnight hours as a 35-45 kt southerly low-level jet develops over the Plains. CAM guidance remains quite dispersive, but some solutions show the potential for isolated severe gusts with elevated storm clusters moving eastward across the Dakotas overnight. A second cluster of elevated storms may be ongoing at the beginning of the period across the eastern Dakotas/western MN associated with a weak shortwave trough and low-level warm advection along the stalled front. If this occurs, a low-end wind/hail threat could exist during the morning as the shortwave continues east/southeastward toward the Great Lakes. Buoyancy and ascent should decrease quickly with eastward extent suggesting only a limited severe risk. ...Four Corners... A shortwave trough and an associated belt of stronger southwesterly flow aloft will be present over portions of the eastern Great Basin and central Rockies Friday. An associated cold front will also shift eastward, impinging upon a modified monsoon air mass across northern AZ/NM into eastern UT and western/central CO. A band of showers and possibly a few thunderstorms are likely be ongoing early in the period ahead of the front. While moisture content (PWATS 0.5-0.8 inches) will not be overly robust, it should be sufficient to support weak diurnal destabilization amid cloud cover and remnant showers/storms. Convection should gradually increase in coverage along the front and across the higher terrain by late morning and early afternoon. The stronger mid-level flow could allow for a few storms to organize into mutlicell clusters or weak supercells. With steep low and mid-level lapse rates present, strong gusts appear possible with any sustained storms, along with small hail. ..Lyons.. 09/11/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE FOUR CORNERS... ...SUMMARY... Strong to severe storms capable of isolated severe wind gusts are possible across the Four Corners region on Friday. Additional storms are possible over the northern Plains and Upper Midwest Friday. ...Northern Plains and Upper Midwest... A shortwave trough and enhanced southwesterly flow will move out of the northern Rockies and into the northern Plains Friday as upper ridging begins to move eastward. Associated with the approaching trough, a weak lee cyclone along a stalled front over the Dakotas will draw rich low-level moisture westward toward a second weak cold front moving out of the Rockies. Modest ascent is expected much of the day along and north of the surface low/front across northern WY, western ND and central/eastern MT. While cloud cover and early morning convection may temper heating somewhat, elevated buoyancy is expected to support scattered to numerous storms through the afternoon. With 35-45 kt of southwesterly flow aloft extending mid and upper-level hodographs, a few elevated clusters or supercells are possible. Steep mid-level lapse rates and favorable deep-layer shear could support isolated hail and strong gusts with the strongest storms, though confidence in the overall severe risk remains fairly low given the potential for clouds and early morning storms. Convective coverage may increase through the evening and overnight hours as a 35-45 kt southerly low-level jet develops over the Plains. CAM guidance remains quite dispersive, but some solutions show the potential for isolated severe gusts with elevated storm clusters moving eastward across the Dakotas overnight. A second cluster of elevated storms may be ongoing at the beginning of the period across the eastern Dakotas/western MN associated with a weak shortwave trough and low-level warm advection along the stalled front. If this occurs, a low-end wind/hail threat could exist during the morning as the shortwave continues east/southeastward toward the Great Lakes. Buoyancy and ascent should decrease quickly with eastward extent suggesting only a limited severe risk. ...Four Corners... A shortwave trough and an associated belt of stronger southwesterly flow aloft will be present over portions of the eastern Great Basin and central Rockies Friday. An associated cold front will also shift eastward, impinging upon a modified monsoon air mass across northern AZ/NM into eastern UT and western/central CO. A band of showers and possibly a few thunderstorms are likely be ongoing early in the period ahead of the front. While moisture content (PWATS 0.5-0.8 inches) will not be overly robust, it should be sufficient to support weak diurnal destabilization amid cloud cover and remnant showers/storms. Convection should gradually increase in coverage along the front and across the higher terrain by late morning and early afternoon. The stronger mid-level flow could allow for a few storms to organize into mutlicell clusters or weak supercells. With steep low and mid-level lapse rates present, strong gusts appear possible with any sustained storms, along with small hail. ..Lyons.. 09/11/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE FOUR CORNERS... ...SUMMARY... Strong to severe storms capable of isolated severe wind gusts are possible across the Four Corners region on Friday. Additional storms are possible over the northern Plains and Upper Midwest Friday. ...Northern Plains and Upper Midwest... A shortwave trough and enhanced southwesterly flow will move out of the northern Rockies and into the northern Plains Friday as upper ridging begins to move eastward. Associated with the approaching trough, a weak lee cyclone along a stalled front over the Dakotas will draw rich low-level moisture westward toward a second weak cold front moving out of the Rockies. Modest ascent is expected much of the day along and north of the surface low/front across northern WY, western ND and central/eastern MT. While cloud cover and early morning convection may temper heating somewhat, elevated buoyancy is expected to support scattered to numerous storms through the afternoon. With 35-45 kt of southwesterly flow aloft extending mid and upper-level hodographs, a few elevated clusters or supercells are possible. Steep mid-level lapse rates and favorable deep-layer shear could support isolated hail and strong gusts with the strongest storms, though confidence in the overall severe risk remains fairly low given the potential for clouds and early morning storms. Convective coverage may increase through the evening and overnight hours as a 35-45 kt southerly low-level jet develops over the Plains. CAM guidance remains quite dispersive, but some solutions show the potential for isolated severe gusts with elevated storm clusters moving eastward across the Dakotas overnight. A second cluster of elevated storms may be ongoing at the beginning of the period across the eastern Dakotas/western MN associated with a weak shortwave trough and low-level warm advection along the stalled front. If this occurs, a low-end wind/hail threat could exist during the morning as the shortwave continues east/southeastward toward the Great Lakes. Buoyancy and ascent should decrease quickly with eastward extent suggesting only a limited severe risk. ...Four Corners... A shortwave trough and an associated belt of stronger southwesterly flow aloft will be present over portions of the eastern Great Basin and central Rockies Friday. An associated cold front will also shift eastward, impinging upon a modified monsoon air mass across northern AZ/NM into eastern UT and western/central CO. A band of showers and possibly a few thunderstorms are likely be ongoing early in the period ahead of the front. While moisture content (PWATS 0.5-0.8 inches) will not be overly robust, it should be sufficient to support weak diurnal destabilization amid cloud cover and remnant showers/storms. Convection should gradually increase in coverage along the front and across the higher terrain by late morning and early afternoon. The stronger mid-level flow could allow for a few storms to organize into mutlicell clusters or weak supercells. With steep low and mid-level lapse rates present, strong gusts appear possible with any sustained storms, along with small hail. ..Lyons.. 09/11/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE FOUR CORNERS... ...SUMMARY... Strong to severe storms capable of isolated severe wind gusts are possible across the Four Corners region on Friday. Additional storms are possible over the northern Plains and Upper Midwest Friday. ...Northern Plains and Upper Midwest... A shortwave trough and enhanced southwesterly flow will move out of the northern Rockies and into the northern Plains Friday as upper ridging begins to move eastward. Associated with the approaching trough, a weak lee cyclone along a stalled front over the Dakotas will draw rich low-level moisture westward toward a second weak cold front moving out of the Rockies. Modest ascent is expected much of the day along and north of the surface low/front across northern WY, western ND and central/eastern MT. While cloud cover and early morning convection may temper heating somewhat, elevated buoyancy is expected to support scattered to numerous storms through the afternoon. With 35-45 kt of southwesterly flow aloft extending mid and upper-level hodographs, a few elevated clusters or supercells are possible. Steep mid-level lapse rates and favorable deep-layer shear could support isolated hail and strong gusts with the strongest storms, though confidence in the overall severe risk remains fairly low given the potential for clouds and early morning storms. Convective coverage may increase through the evening and overnight hours as a 35-45 kt southerly low-level jet develops over the Plains. CAM guidance remains quite dispersive, but some solutions show the potential for isolated severe gusts with elevated storm clusters moving eastward across the Dakotas overnight. A second cluster of elevated storms may be ongoing at the beginning of the period across the eastern Dakotas/western MN associated with a weak shortwave trough and low-level warm advection along the stalled front. If this occurs, a low-end wind/hail threat could exist during the morning as the shortwave continues east/southeastward toward the Great Lakes. Buoyancy and ascent should decrease quickly with eastward extent suggesting only a limited severe risk. ...Four Corners... A shortwave trough and an associated belt of stronger southwesterly flow aloft will be present over portions of the eastern Great Basin and central Rockies Friday. An associated cold front will also shift eastward, impinging upon a modified monsoon air mass across northern AZ/NM into eastern UT and western/central CO. A band of showers and possibly a few thunderstorms are likely be ongoing early in the period ahead of the front. While moisture content (PWATS 0.5-0.8 inches) will not be overly robust, it should be sufficient to support weak diurnal destabilization amid cloud cover and remnant showers/storms. Convection should gradually increase in coverage along the front and across the higher terrain by late morning and early afternoon. The stronger mid-level flow could allow for a few storms to organize into mutlicell clusters or weak supercells. With steep low and mid-level lapse rates present, strong gusts appear possible with any sustained storms, along with small hail. ..Lyons.. 09/11/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 11 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... A corridor of strong to severe thunderstorms with hail and damaging gusts are expected from eastern Montana into western North Dakota, while isolated/localized wind or marginal hail will be possible across a large portion of the Rockies. ...Synopsis... A large, positive-tilt upper trough will remain nearly stationary across the western CONUS, with axis extending from western NV into southern MB/SK. East of this trough, a broad fetch of 30-40 kt 500 mb southwesterlies will affect much of the Rockies and disturbances rounding the upper ridge into the northern Plains. At the surface, high pressure will maintain stable conditions over much of the East, where a elongated/weak upper trough will exist. Southerly surface winds will maintain a low-level moist plume across the MO Valley with 60s F dewpoints, with 50s F into much of eastern MT where surface winds will back to southeasterly. The combination of daytime heating and substantial southwest flow aloft across a large part of the Rockies, along with at least marginal instability over a wide area suggest sporadic strong to severe storms will be possible during the afternoon and evening. ...Rockies into the northern Plains... Lapse rates will steepen over the area as heating commences, and with the 500 mb -10 C isotherm extending from SD to southern UT. By virtue of an uncapped air mass, sporadic afternoon storms are likely over the higher terrain over northwest NM, CO, and over much of ID into MT, while warm and drier air will generally be found from UT into parts of central WY. However, even in the drier areas, a few storms are likely as weak levels of instability develop. Conditionally, the entire region will have deep-layer shear at or above 35-40 kt, which will favor cellular storm mode. Small hail appears most likely over much of the Intermountain West, with locally strong gusts as well. A potentially greater severe threat will extend from eastern MT and WY into the western Dakotas, where moisture and instability will be greater. A surface low is expected over southeast MT/northwest SD, with backed/moist winds wrapping west. Forecast soundings in this area depict robust CAPE profiles and hodographs favoring cells producing hail, or perhaps bowing structures with both wind and hail risk. Storms may form over south-central MT/northern WY after 21Z, moving into the western Dakotas during the evening. ..Jewell/Wendt.. 09/11/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Thu Sep 11 2025 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... A corridor of strong to severe thunderstorms with hail and damaging gusts are expected from eastern Montana into western North Dakota, while isolated/localized wind or marginal hail will be possible across a large portion of the Rockies. ...Synopsis... A large, positive-tilt upper trough will remain nearly stationary across the western CONUS, with axis extending from western NV into southern MB/SK. East of this trough, a broad fetch of 30-40 kt 500 mb southwesterlies will affect much of the Rockies and disturbances rounding the upper ridge into the northern Plains. At the surface, high pressure will maintain stable conditions over much of the East, where a elongated/weak upper trough will exist. Southerly surface winds will maintain a low-level moist plume across the MO Valley with 60s F dewpoints, with 50s F into much of eastern MT where surface winds will back to southeasterly. The combination of daytime heating and substantial southwest flow aloft across a large part of the Rockies, along with at least marginal instability over a wide area suggest sporadic strong to severe storms will be possible during the afternoon and evening. ...Rockies into the northern Plains... Lapse rates will steepen over the area as heating commences, and with the 500 mb -10 C isotherm extending from SD to southern UT. By virtue of an uncapped air mass, sporadic afternoon storms are likely over the higher terrain over northwest NM, CO, and over much of ID into MT, while warm and drier air will generally be found from UT into parts of central WY. However, even in the drier areas, a few storms are likely as weak levels of instability develop. Conditionally, the entire region will have deep-layer shear at or above 35-40 kt, which will favor cellular storm mode. Small hail appears most likely over much of the Intermountain West, with locally strong gusts as well. A potentially greater severe threat will extend from eastern MT and WY into the western Dakotas, where moisture and instability will be greater. A surface low is expected over southeast MT/northwest SD, with backed/moist winds wrapping west. Forecast soundings in this area depict robust CAPE profiles and hodographs favoring cells producing hail, or perhaps bowing structures with both wind and hail risk. Storms may form over south-central MT/northern WY after 21Z, moving into the western Dakotas during the evening. ..Jewell/Wendt.. 09/11/2025 Read more