Severe Storms

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

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

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 NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1105 AM CDT Thu Sep 11 2025 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...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 NWS Storm Prediction Center Norman OK Issued by 15th OWS Scott Air Force Base IL 1105 AM CDT Thu Sep 11 2025 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...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 Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...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. ...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 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...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. ...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 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...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. ...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 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...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. ...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 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...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. ...Please see www.spc.noaa.gov/fire for graphic product... Read more