Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0235 PM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... Mid-level flow ahead of an upper-level trough over the western U.S. will become more diffuse through the Day 2 period. This will aid in reducing daytime surface winds across portions of the Southwest and in particular Utah. Locally elevated fire weather conditions are still expected across northwestern Arizona and southern Utah Friday with southwest winds of up to 15 mph and relative humidity falling to around 15% by the afternoon. However, fuel dryness is lacking to allow for significant wildfire spread. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0118 AM CDT Thu Sep 11 2025/ ...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. ...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 0235 PM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... Mid-level flow ahead of an upper-level trough over the western U.S. will become more diffuse through the Day 2 period. This will aid in reducing daytime surface winds across portions of the Southwest and in particular Utah. Locally elevated fire weather conditions are still expected across northwestern Arizona and southern Utah Friday with southwest winds of up to 15 mph and relative humidity falling to around 15% by the afternoon. However, fuel dryness is lacking to allow for significant wildfire spread. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0118 AM CDT Thu Sep 11 2025/ ...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. ...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 0235 PM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... Mid-level flow ahead of an upper-level trough over the western U.S. will become more diffuse through the Day 2 period. This will aid in reducing daytime surface winds across portions of the Southwest and in particular Utah. Locally elevated fire weather conditions are still expected across northwestern Arizona and southern Utah Friday with southwest winds of up to 15 mph and relative humidity falling to around 15% by the afternoon. However, fuel dryness is lacking to allow for significant wildfire spread. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0118 AM CDT Thu Sep 11 2025/ ...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. ...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 0235 PM CDT Thu Sep 11 2025 Valid 121200Z - 131200Z ...NO CRITICAL AREAS... Mid-level flow ahead of an upper-level trough over the western U.S. will become more diffuse through the Day 2 period. This will aid in reducing daytime surface winds across portions of the Southwest and in particular Utah. Locally elevated fire weather conditions are still expected across northwestern Arizona and southern Utah Friday with southwest winds of up to 15 mph and relative humidity falling to around 15% by the afternoon. However, fuel dryness is lacking to allow for significant wildfire spread. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0118 AM CDT Thu Sep 11 2025/ ...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. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE CENTRAL/SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible over parts of the southern and central High Plains and northern Plains Saturday. Scattered to numerous storms are also possible over the Midwest, though confidence in severe potential is lower here. ...Synopsis... A large, negatively-tilted trough will shift east across the Rockies on Saturday with a weak lee cyclone across the northern Plains. A dry, continental airmass will be in place across the eastern CONUS where high pressure will be in place. ...Southern/central High Plains... Low-level moisture advection across the High Plains, combined with cooling temperatures aloft will lead to some destabilization across eastern New Mexico and into the central High Plains Saturday afternoon. Overall heating/instability will likely be somewhat muted by cloudcover ahead of the upper-level trough. Nonetheless, as the cold front advances east of the terrain and interacts with weak to potentially moderate instability, stronger updrafts may develop. Around 40 knots of mid-level flow will result in moderate instability and the potential for some storm organization. Overall expect limited instability to keep the threat limited/isolated. ...Northern Plains... Guidance consistently shows moisture wrapping around the northern portion of a cyclone across South Dakota Saturday morning, this moisture, combined with cooling temperatures aloft and isentropic ascent may result in a few elevated thunderstorms capable of large hail on Saturday morning. Additional storms may develop north of the surface low as temperatures cool aloft and some surface-based instability develops in the wake of morning storms. This environment may also support a few strong storms capable of isolated damaging winds/large hail. ..Bentley.. 09/11/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE CENTRAL/SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible over parts of the southern and central High Plains and northern Plains Saturday. Scattered to numerous storms are also possible over the Midwest, though confidence in severe potential is lower here. ...Synopsis... A large, negatively-tilted trough will shift east across the Rockies on Saturday with a weak lee cyclone across the northern Plains. A dry, continental airmass will be in place across the eastern CONUS where high pressure will be in place. ...Southern/central High Plains... Low-level moisture advection across the High Plains, combined with cooling temperatures aloft will lead to some destabilization across eastern New Mexico and into the central High Plains Saturday afternoon. Overall heating/instability will likely be somewhat muted by cloudcover ahead of the upper-level trough. Nonetheless, as the cold front advances east of the terrain and interacts with weak to potentially moderate instability, stronger updrafts may develop. Around 40 knots of mid-level flow will result in moderate instability and the potential for some storm organization. Overall expect limited instability to keep the threat limited/isolated. ...Northern Plains... Guidance consistently shows moisture wrapping around the northern portion of a cyclone across South Dakota Saturday morning, this moisture, combined with cooling temperatures aloft and isentropic ascent may result in a few elevated thunderstorms capable of large hail on Saturday morning. Additional storms may develop north of the surface low as temperatures cool aloft and some surface-based instability develops in the wake of morning storms. This environment may also support a few strong storms capable of isolated damaging winds/large hail. ..Bentley.. 09/11/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE CENTRAL/SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible over parts of the southern and central High Plains and northern Plains Saturday. Scattered to numerous storms are also possible over the Midwest, though confidence in severe potential is lower here. ...Synopsis... A large, negatively-tilted trough will shift east across the Rockies on Saturday with a weak lee cyclone across the northern Plains. A dry, continental airmass will be in place across the eastern CONUS where high pressure will be in place. ...Southern/central High Plains... Low-level moisture advection across the High Plains, combined with cooling temperatures aloft will lead to some destabilization across eastern New Mexico and into the central High Plains Saturday afternoon. Overall heating/instability will likely be somewhat muted by cloudcover ahead of the upper-level trough. Nonetheless, as the cold front advances east of the terrain and interacts with weak to potentially moderate instability, stronger updrafts may develop. Around 40 knots of mid-level flow will result in moderate instability and the potential for some storm organization. Overall expect limited instability to keep the threat limited/isolated. ...Northern Plains... Guidance consistently shows moisture wrapping around the northern portion of a cyclone across South Dakota Saturday morning, this moisture, combined with cooling temperatures aloft and isentropic ascent may result in a few elevated thunderstorms capable of large hail on Saturday morning. Additional storms may develop north of the surface low as temperatures cool aloft and some surface-based instability develops in the wake of morning storms. This environment may also support a few strong storms capable of isolated damaging winds/large hail. ..Bentley.. 09/11/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE CENTRAL/SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible over parts of the southern and central High Plains and northern Plains Saturday. Scattered to numerous storms are also possible over the Midwest, though confidence in severe potential is lower here. ...Synopsis... A large, negatively-tilted trough will shift east across the Rockies on Saturday with a weak lee cyclone across the northern Plains. A dry, continental airmass will be in place across the eastern CONUS where high pressure will be in place. ...Southern/central High Plains... Low-level moisture advection across the High Plains, combined with cooling temperatures aloft will lead to some destabilization across eastern New Mexico and into the central High Plains Saturday afternoon. Overall heating/instability will likely be somewhat muted by cloudcover ahead of the upper-level trough. Nonetheless, as the cold front advances east of the terrain and interacts with weak to potentially moderate instability, stronger updrafts may develop. Around 40 knots of mid-level flow will result in moderate instability and the potential for some storm organization. Overall expect limited instability to keep the threat limited/isolated. ...Northern Plains... Guidance consistently shows moisture wrapping around the northern portion of a cyclone across South Dakota Saturday morning, this moisture, combined with cooling temperatures aloft and isentropic ascent may result in a few elevated thunderstorms capable of large hail on Saturday morning. Additional storms may develop north of the surface low as temperatures cool aloft and some surface-based instability develops in the wake of morning storms. This environment may also support a few strong storms capable of isolated damaging winds/large hail. ..Bentley.. 09/11/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE CENTRAL/SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible over parts of the southern and central High Plains and northern Plains Saturday. Scattered to numerous storms are also possible over the Midwest, though confidence in severe potential is lower here. ...Synopsis... A large, negatively-tilted trough will shift east across the Rockies on Saturday with a weak lee cyclone across the northern Plains. A dry, continental airmass will be in place across the eastern CONUS where high pressure will be in place. ...Southern/central High Plains... Low-level moisture advection across the High Plains, combined with cooling temperatures aloft will lead to some destabilization across eastern New Mexico and into the central High Plains Saturday afternoon. Overall heating/instability will likely be somewhat muted by cloudcover ahead of the upper-level trough. Nonetheless, as the cold front advances east of the terrain and interacts with weak to potentially moderate instability, stronger updrafts may develop. Around 40 knots of mid-level flow will result in moderate instability and the potential for some storm organization. Overall expect limited instability to keep the threat limited/isolated. ...Northern Plains... Guidance consistently shows moisture wrapping around the northern portion of a cyclone across South Dakota Saturday morning, this moisture, combined with cooling temperatures aloft and isentropic ascent may result in a few elevated thunderstorms capable of large hail on Saturday morning. Additional storms may develop north of the surface low as temperatures cool aloft and some surface-based instability develops in the wake of morning storms. This environment may also support a few strong storms capable of isolated damaging winds/large hail. ..Bentley.. 09/11/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE CENTRAL/SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible over parts of the southern and central High Plains and northern Plains Saturday. Scattered to numerous storms are also possible over the Midwest, though confidence in severe potential is lower here. ...Synopsis... A large, negatively-tilted trough will shift east across the Rockies on Saturday with a weak lee cyclone across the northern Plains. A dry, continental airmass will be in place across the eastern CONUS where high pressure will be in place. ...Southern/central High Plains... Low-level moisture advection across the High Plains, combined with cooling temperatures aloft will lead to some destabilization across eastern New Mexico and into the central High Plains Saturday afternoon. Overall heating/instability will likely be somewhat muted by cloudcover ahead of the upper-level trough. Nonetheless, as the cold front advances east of the terrain and interacts with weak to potentially moderate instability, stronger updrafts may develop. Around 40 knots of mid-level flow will result in moderate instability and the potential for some storm organization. Overall expect limited instability to keep the threat limited/isolated. ...Northern Plains... Guidance consistently shows moisture wrapping around the northern portion of a cyclone across South Dakota Saturday morning, this moisture, combined with cooling temperatures aloft and isentropic ascent may result in a few elevated thunderstorms capable of large hail on Saturday morning. Additional storms may develop north of the surface low as temperatures cool aloft and some surface-based instability develops in the wake of morning storms. This environment may also support a few strong storms capable of isolated damaging winds/large hail. ..Bentley.. 09/11/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN PLAINS AND THE CENTRAL/SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms are possible over parts of the southern and central High Plains and northern Plains Saturday. Scattered to numerous storms are also possible over the Midwest, though confidence in severe potential is lower here. ...Synopsis... A large, negatively-tilted trough will shift east across the Rockies on Saturday with a weak lee cyclone across the northern Plains. A dry, continental airmass will be in place across the eastern CONUS where high pressure will be in place. ...Southern/central High Plains... Low-level moisture advection across the High Plains, combined with cooling temperatures aloft will lead to some destabilization across eastern New Mexico and into the central High Plains Saturday afternoon. Overall heating/instability will likely be somewhat muted by cloudcover ahead of the upper-level trough. Nonetheless, as the cold front advances east of the terrain and interacts with weak to potentially moderate instability, stronger updrafts may develop. Around 40 knots of mid-level flow will result in moderate instability and the potential for some storm organization. Overall expect limited instability to keep the threat limited/isolated. ...Northern Plains... Guidance consistently shows moisture wrapping around the northern portion of a cyclone across South Dakota Saturday morning, this moisture, combined with cooling temperatures aloft and isentropic ascent may result in a few elevated thunderstorms capable of large hail on Saturday morning. Additional storms may develop north of the surface low as temperatures cool aloft and some surface-based instability develops in the wake of morning storms. This environment may also support a few strong storms capable of isolated damaging winds/large hail. ..Bentley.. 09/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1205 PM 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. ..15_ows.. 09/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1205 PM 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. ..15_ows.. 09/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1205 PM 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. ..15_ows.. 09/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1205 PM 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. ..15_ows.. 09/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1205 PM 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. ..15_ows.. 09/11/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1205 PM 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. ..15_ows.. 09/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 1221 PM CDT Thu Sep 11 2025 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... CORRECTED FOR PROB GRAPHICS ...SUMMARY... Scattered severe thunderstorms are expected over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe wind gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..15_ows.. 09/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 1221 PM CDT Thu Sep 11 2025 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... CORRECTED FOR PROB GRAPHICS ...SUMMARY... Scattered severe thunderstorms are expected over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe wind gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..15_ows.. 09/11/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 1221 PM CDT Thu Sep 11 2025 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... CORRECTED FOR PROB GRAPHICS ...SUMMARY... Scattered severe thunderstorms are expected over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe wind gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..15_ows.. 09/11/2025 Read more