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SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Central and Southern Plains... A substantial midlevel wave will track southeastward across the central Rockies into the adjacent High Plains on Monday. In the low-levels, a surface front will extend from NE southward across western KS to an evolving triple point in the vicinity of southwest KS. In response to the approaching wave, strong low-level positive theta-e advection beneath a robust EML will yield a strongly unstable air mass across parts of the southern and central Plains. As midlevel height falls preceding the wave impinge on the surface boundary and triple point, inhibition at the base of the EML should gradually erode and support widely scattered thunderstorms by late afternoon. Around 40-50 kt of off-boundary deep-layer shear should initially support semi-discrete supercells with a risk of large hail and severe wind gusts across parts of western KS into the eastern OK/TX Panhandles. Additional strong to severe thunderstorms are expected farther north along the surface front into NE, though deep-layer shear will be weaker here in comparison. With time, thunderstorms will spread/develop east-southeastward across KS and western/central OK into a strengthening southerly low-level jet during the evening/overnight hours. This should promote a continuation of embedded supercells and upscale growth into one or more southeastward-moving MCSs. Severe hail and swath of wind damage will be possible with this convective evolution. ..Weinman.. 09/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Central and Southern Plains... A substantial midlevel wave will track southeastward across the central Rockies into the adjacent High Plains on Monday. In the low-levels, a surface front will extend from NE southward across western KS to an evolving triple point in the vicinity of southwest KS. In response to the approaching wave, strong low-level positive theta-e advection beneath a robust EML will yield a strongly unstable air mass across parts of the southern and central Plains. As midlevel height falls preceding the wave impinge on the surface boundary and triple point, inhibition at the base of the EML should gradually erode and support widely scattered thunderstorms by late afternoon. Around 40-50 kt of off-boundary deep-layer shear should initially support semi-discrete supercells with a risk of large hail and severe wind gusts across parts of western KS into the eastern OK/TX Panhandles. Additional strong to severe thunderstorms are expected farther north along the surface front into NE, though deep-layer shear will be weaker here in comparison. With time, thunderstorms will spread/develop east-southeastward across KS and western/central OK into a strengthening southerly low-level jet during the evening/overnight hours. This should promote a continuation of embedded supercells and upscale growth into one or more southeastward-moving MCSs. Severe hail and swath of wind damage will be possible with this convective evolution. ..Weinman.. 09/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Central and Southern Plains... A substantial midlevel wave will track southeastward across the central Rockies into the adjacent High Plains on Monday. In the low-levels, a surface front will extend from NE southward across western KS to an evolving triple point in the vicinity of southwest KS. In response to the approaching wave, strong low-level positive theta-e advection beneath a robust EML will yield a strongly unstable air mass across parts of the southern and central Plains. As midlevel height falls preceding the wave impinge on the surface boundary and triple point, inhibition at the base of the EML should gradually erode and support widely scattered thunderstorms by late afternoon. Around 40-50 kt of off-boundary deep-layer shear should initially support semi-discrete supercells with a risk of large hail and severe wind gusts across parts of western KS into the eastern OK/TX Panhandles. Additional strong to severe thunderstorms are expected farther north along the surface front into NE, though deep-layer shear will be weaker here in comparison. With time, thunderstorms will spread/develop east-southeastward across KS and western/central OK into a strengthening southerly low-level jet during the evening/overnight hours. This should promote a continuation of embedded supercells and upscale growth into one or more southeastward-moving MCSs. Severe hail and swath of wind damage will be possible with this convective evolution. ..Weinman.. 09/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Central and Southern Plains... A substantial midlevel wave will track southeastward across the central Rockies into the adjacent High Plains on Monday. In the low-levels, a surface front will extend from NE southward across western KS to an evolving triple point in the vicinity of southwest KS. In response to the approaching wave, strong low-level positive theta-e advection beneath a robust EML will yield a strongly unstable air mass across parts of the southern and central Plains. As midlevel height falls preceding the wave impinge on the surface boundary and triple point, inhibition at the base of the EML should gradually erode and support widely scattered thunderstorms by late afternoon. Around 40-50 kt of off-boundary deep-layer shear should initially support semi-discrete supercells with a risk of large hail and severe wind gusts across parts of western KS into the eastern OK/TX Panhandles. Additional strong to severe thunderstorms are expected farther north along the surface front into NE, though deep-layer shear will be weaker here in comparison. With time, thunderstorms will spread/develop east-southeastward across KS and western/central OK into a strengthening southerly low-level jet during the evening/overnight hours. This should promote a continuation of embedded supercells and upscale growth into one or more southeastward-moving MCSs. Severe hail and swath of wind damage will be possible with this convective evolution. ..Weinman.. 09/20/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 PM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF SOUTHWEST/SOUTH-CENTRAL KANSAS...WESTERN/CENTRAL OKLAHOMA...AND THE EASTERN TEXAS/OKLAHOMA PANHANDLES... ...SUMMARY... Scattered severe thunderstorms will be possible on Monday across portions of the central and southern High Plains. ...Central and Southern Plains... A substantial midlevel wave will track southeastward across the central Rockies into the adjacent High Plains on Monday. In the low-levels, a surface front will extend from NE southward across western KS to an evolving triple point in the vicinity of southwest KS. In response to the approaching wave, strong low-level positive theta-e advection beneath a robust EML will yield a strongly unstable air mass across parts of the southern and central Plains. As midlevel height falls preceding the wave impinge on the surface boundary and triple point, inhibition at the base of the EML should gradually erode and support widely scattered thunderstorms by late afternoon. Around 40-50 kt of off-boundary deep-layer shear should initially support semi-discrete supercells with a risk of large hail and severe wind gusts across parts of western KS into the eastern OK/TX Panhandles. Additional strong to severe thunderstorms are expected farther north along the surface front into NE, though deep-layer shear will be weaker here in comparison. With time, thunderstorms will spread/develop east-southeastward across KS and western/central OK into a strengthening southerly low-level jet during the evening/overnight hours. This should promote a continuation of embedded supercells and upscale growth into one or more southeastward-moving MCSs. Severe hail and swath of wind damage will be possible with this convective evolution. ..Weinman.. 09/20/2025 Read more

024
ABPZ20 KNHC 201750
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sat Sep 20 2025

For the eastern and central North Pacific east of 180 longitude:

South of the Baja California Peninsula (EP96):
Shower and thunderstorm activity has diminished in association with
an area of low pressure located a few hundred miles southwest of the
southern tip of the Baja California Peninsula. The system is moving
into an unfavorable environment, and development is no longer
expected.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...near 0 percent.

Off the Coast of Southern Mexico (EP97):
A broad area of low pressure located a couple of hundred miles south
of the southern coast of Mexico is producing a persistent but
disorganized area of showers and thunderstorms. Environmental
conditions are favorable for continued development, and a tropical
depression or tropical storm is expected to form within the next
couple of days while it moves west-northwestward at 5 to 10 mph,
roughly parallel to the coast of southern and southwestern Mexico.
The system could produce some locally heavy rain along portions of
the coast of southern and southwestern Mexico through Monday.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...90 percent.

$$
Forecaster Hagen

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ...North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ...Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ...Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ..Weinman.. 09/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ...North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ...Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ...Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ..Weinman.. 09/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ...North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ...Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ...Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ..Weinman.. 09/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ...North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ...Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ...Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ..Weinman.. 09/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ...North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ...Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ...Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ..Weinman.. 09/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ...North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ...Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ...Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ..Weinman.. 09/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTH TEXAS...THE MIDDLE MISSOURI VALLEY...AND THE OHIO VALLEY INTO THE GREAT LAKES... ...SUMMARY... Isolated severe thunderstorms are possible across parts of north Texas and the Middle Missouri Valley, with the main risk being large hail. A few strong to severe thunderstorms capable of locally damaging gusts are possible across parts of the Ohio Valley into the Great Lakes. ...North Texas... Convection will likely be ongoing across southwest OK into western north TX at the start of the forecast period, which should lay out an outflow boundary across parts of north TX. Along/south of the outflow boundary and to the east of a lee trough/dryline feature, boundary-layer moisture advection and ample diurnal heating beneath relatively steep midlevel lapse rates will contribute to strong surface-based buoyancy and minimal inhibition by the afternoon. Aided by a glancing midlevel wave and related jet streak crossing western OK, isolated to widely scattered thunderstorms are expected near the lee trough and residual outflow boundary during the afternoon. A long/straight hodograph (around 40-50 kt of effective shear) and the aforementioned buoyancy should promote a couple splitting supercell structures, posing a risk of large hail. Severe wind gusts will also be possible, especially with any convective clustering that occurs with southeastward extent. ...Ohio Valley and Great Lakes... Downstream of a midlevel trough moving across the Upper MS Valley, broad/enhanced midlevel southwesterly flow will overspread a weak to moderately unstable and uncapped warm sector extending from the OH Valley into the Great Lakes. Potentially aided by a convectively augmented midlevel impulse moving into the Lower OH Valley, widely scattered thunderstorms are expected during the afternoon. Around 20-25 kt of effective shear and a warm/moist PBL will favor a few loosely organized multicell clusters, capable of producing locally damaging gusts through the afternoon. ...Middle Missouri Valley... Within the base of a midlevel trough over the Upper MS Valley, isolated thunderstorms should develop near a weak surface low near southeast SD. While boundary-layer moisture will be limited, cold temperatures aloft/steep lapse rates and sufficient buoyancy should support a couple loosely organized cells. Marginally severe hail will be possible with the stronger storms that evolve during the evening into overnight hours. ..Weinman.. 09/20/2025 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1148 AM CDT Sat Sep 20 2025 Valid 201700Z - 211200Z ...North Cascades into the Columbia Basin... Current observations reveal significant drying on the western fringes of the Columbia Basin where relative humidity has already fallen below 20%, coincident with dewpoints around 20F. An approaching mid-level trough with accompanying increasing west/southwest aloft along with efficient boundary layer mixing under mostly clear skies will support increasing west/southwest winds in the lee of the Cascades and Columbia Basin this afternoon. A shallow temperature inversion within the basin will steadily erode, resulting in sustained west to southwest winds of 10-15 mph (20 mph in Cascade gaps) and relative humidity dropping as low as 10% this afternoon. Elevated highlights were maintained with expected dry and breezy conditions this afternoon amid dry fuels, where ERC values around the 80th percentile remain on the leeward slopes of the Cascades. ..Williams.. 09/20/2025 .PREV DISCUSSION... /ISSUED 1254 AM CDT Sat Sep 20 2025/ ...Synopsis... Elevated fire-weather highlights have been maintained over portions of the eastern North Cascades into the Columbia Basin, associated with west-southwesterly flow aloft from a mid-level trough approaching the U.S./Canada west coast. Weak surface winds and high precipitable water content across the rest of the continental U.S. preclude any other fire-weather highlights. ...North Cascades into the Columbia Basin... Westerly flow aloft will support downslope winds across the North Cascades, with winds of 10-15 MPH (locally as high as 20 MPH in the Cascade gaps) forecast along with relative humidity around 15-20%. With ERCs near the 80th annual percentile, at least Elevated fire-weather highlights are to be maintained today -- though fire-weather concerns are generally limited by the lack of appreciable surface winds. ...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 1148 AM CDT Sat Sep 20 2025 Valid 201700Z - 211200Z ...North Cascades into the Columbia Basin... Current observations reveal significant drying on the western fringes of the Columbia Basin where relative humidity has already fallen below 20%, coincident with dewpoints around 20F. An approaching mid-level trough with accompanying increasing west/southwest aloft along with efficient boundary layer mixing under mostly clear skies will support increasing west/southwest winds in the lee of the Cascades and Columbia Basin this afternoon. A shallow temperature inversion within the basin will steadily erode, resulting in sustained west to southwest winds of 10-15 mph (20 mph in Cascade gaps) and relative humidity dropping as low as 10% this afternoon. Elevated highlights were maintained with expected dry and breezy conditions this afternoon amid dry fuels, where ERC values around the 80th percentile remain on the leeward slopes of the Cascades. ..Williams.. 09/20/2025 .PREV DISCUSSION... /ISSUED 1254 AM CDT Sat Sep 20 2025/ ...Synopsis... Elevated fire-weather highlights have been maintained over portions of the eastern North Cascades into the Columbia Basin, associated with west-southwesterly flow aloft from a mid-level trough approaching the U.S./Canada west coast. Weak surface winds and high precipitable water content across the rest of the continental U.S. preclude any other fire-weather highlights. ...North Cascades into the Columbia Basin... Westerly flow aloft will support downslope winds across the North Cascades, with winds of 10-15 MPH (locally as high as 20 MPH in the Cascade gaps) forecast along with relative humidity around 15-20%. With ERCs near the 80th annual percentile, at least Elevated fire-weather highlights are to be maintained today -- though fire-weather concerns are generally limited by the lack of appreciable surface winds. ...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 1148 AM CDT Sat Sep 20 2025 Valid 201700Z - 211200Z ...North Cascades into the Columbia Basin... Current observations reveal significant drying on the western fringes of the Columbia Basin where relative humidity has already fallen below 20%, coincident with dewpoints around 20F. An approaching mid-level trough with accompanying increasing west/southwest aloft along with efficient boundary layer mixing under mostly clear skies will support increasing west/southwest winds in the lee of the Cascades and Columbia Basin this afternoon. A shallow temperature inversion within the basin will steadily erode, resulting in sustained west to southwest winds of 10-15 mph (20 mph in Cascade gaps) and relative humidity dropping as low as 10% this afternoon. Elevated highlights were maintained with expected dry and breezy conditions this afternoon amid dry fuels, where ERC values around the 80th percentile remain on the leeward slopes of the Cascades. ..Williams.. 09/20/2025 .PREV DISCUSSION... /ISSUED 1254 AM CDT Sat Sep 20 2025/ ...Synopsis... Elevated fire-weather highlights have been maintained over portions of the eastern North Cascades into the Columbia Basin, associated with west-southwesterly flow aloft from a mid-level trough approaching the U.S./Canada west coast. Weak surface winds and high precipitable water content across the rest of the continental U.S. preclude any other fire-weather highlights. ...North Cascades into the Columbia Basin... Westerly flow aloft will support downslope winds across the North Cascades, with winds of 10-15 MPH (locally as high as 20 MPH in the Cascade gaps) forecast along with relative humidity around 15-20%. With ERCs near the 80th annual percentile, at least Elevated fire-weather highlights are to be maintained today -- though fire-weather concerns are generally limited by the lack of appreciable surface winds. ...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 1148 AM CDT Sat Sep 20 2025 Valid 201700Z - 211200Z ...North Cascades into the Columbia Basin... Current observations reveal significant drying on the western fringes of the Columbia Basin where relative humidity has already fallen below 20%, coincident with dewpoints around 20F. An approaching mid-level trough with accompanying increasing west/southwest aloft along with efficient boundary layer mixing under mostly clear skies will support increasing west/southwest winds in the lee of the Cascades and Columbia Basin this afternoon. A shallow temperature inversion within the basin will steadily erode, resulting in sustained west to southwest winds of 10-15 mph (20 mph in Cascade gaps) and relative humidity dropping as low as 10% this afternoon. Elevated highlights were maintained with expected dry and breezy conditions this afternoon amid dry fuels, where ERC values around the 80th percentile remain on the leeward slopes of the Cascades. ..Williams.. 09/20/2025 .PREV DISCUSSION... /ISSUED 1254 AM CDT Sat Sep 20 2025/ ...Synopsis... Elevated fire-weather highlights have been maintained over portions of the eastern North Cascades into the Columbia Basin, associated with west-southwesterly flow aloft from a mid-level trough approaching the U.S./Canada west coast. Weak surface winds and high precipitable water content across the rest of the continental U.S. preclude any other fire-weather highlights. ...North Cascades into the Columbia Basin... Westerly flow aloft will support downslope winds across the North Cascades, with winds of 10-15 MPH (locally as high as 20 MPH in the Cascade gaps) forecast along with relative humidity around 15-20%. With ERCs near the 80th annual percentile, at least Elevated fire-weather highlights are to be maintained today -- though fire-weather concerns are generally limited by the lack of appreciable surface winds. ...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 1148 AM CDT Sat Sep 20 2025 Valid 201700Z - 211200Z ...North Cascades into the Columbia Basin... Current observations reveal significant drying on the western fringes of the Columbia Basin where relative humidity has already fallen below 20%, coincident with dewpoints around 20F. An approaching mid-level trough with accompanying increasing west/southwest aloft along with efficient boundary layer mixing under mostly clear skies will support increasing west/southwest winds in the lee of the Cascades and Columbia Basin this afternoon. A shallow temperature inversion within the basin will steadily erode, resulting in sustained west to southwest winds of 10-15 mph (20 mph in Cascade gaps) and relative humidity dropping as low as 10% this afternoon. Elevated highlights were maintained with expected dry and breezy conditions this afternoon amid dry fuels, where ERC values around the 80th percentile remain on the leeward slopes of the Cascades. ..Williams.. 09/20/2025 .PREV DISCUSSION... /ISSUED 1254 AM CDT Sat Sep 20 2025/ ...Synopsis... Elevated fire-weather highlights have been maintained over portions of the eastern North Cascades into the Columbia Basin, associated with west-southwesterly flow aloft from a mid-level trough approaching the U.S./Canada west coast. Weak surface winds and high precipitable water content across the rest of the continental U.S. preclude any other fire-weather highlights. ...North Cascades into the Columbia Basin... Westerly flow aloft will support downslope winds across the North Cascades, with winds of 10-15 MPH (locally as high as 20 MPH in the Cascade gaps) forecast along with relative humidity around 15-20%. With ERCs near the 80th annual percentile, at least Elevated fire-weather highlights are to be maintained today -- though fire-weather concerns are generally limited by the lack of appreciable surface winds. ...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 1148 AM CDT Sat Sep 20 2025 Valid 201700Z - 211200Z ...North Cascades into the Columbia Basin... Current observations reveal significant drying on the western fringes of the Columbia Basin where relative humidity has already fallen below 20%, coincident with dewpoints around 20F. An approaching mid-level trough with accompanying increasing west/southwest aloft along with efficient boundary layer mixing under mostly clear skies will support increasing west/southwest winds in the lee of the Cascades and Columbia Basin this afternoon. A shallow temperature inversion within the basin will steadily erode, resulting in sustained west to southwest winds of 10-15 mph (20 mph in Cascade gaps) and relative humidity dropping as low as 10% this afternoon. Elevated highlights were maintained with expected dry and breezy conditions this afternoon amid dry fuels, where ERC values around the 80th percentile remain on the leeward slopes of the Cascades. ..Williams.. 09/20/2025 .PREV DISCUSSION... /ISSUED 1254 AM CDT Sat Sep 20 2025/ ...Synopsis... Elevated fire-weather highlights have been maintained over portions of the eastern North Cascades into the Columbia Basin, associated with west-southwesterly flow aloft from a mid-level trough approaching the U.S./Canada west coast. Weak surface winds and high precipitable water content across the rest of the continental U.S. preclude any other fire-weather highlights. ...North Cascades into the Columbia Basin... Westerly flow aloft will support downslope winds across the North Cascades, with winds of 10-15 MPH (locally as high as 20 MPH in the Cascade gaps) forecast along with relative humidity around 15-20%. With ERCs near the 80th annual percentile, at least Elevated fire-weather highlights are to be maintained today -- though fire-weather concerns are generally limited by the lack of appreciable surface winds. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1115 AM CDT Sat Sep 20 2025 Valid 201630Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTH-CENTRAL PLAINS... ...SUMMARY... Scattered strong to locally severe thunderstorms may impact parts of the south-central Plains this afternoon and evening, accompanied by an isolated threat for strong to severe wind gusts and marginally severe hail. ...South-Central Plains... Visible-satellite imagery late this morning shows a couple of small thunderstorm clusters over parts of the Ozarks into northeast OK and mostly clear skies farther west and southwest over OK into the TX Panhandle. Surface analysis places a zone of outflow extending from west-central AR northwestward into north-central OK. The primary front arcs from the OK Panhandle vicinity northeastward into central/eastern KS. A moist and moderately unstable airmass is forecast by mid-late afternoon across the Marginal Risk. A relatively non-descript upper pattern, north of a flattened upper ridge, features a couple of very minor perturbations slowly moving east across the central High Plains into the mid MS Valley, to the south of more amplified disturbances over the upper MS Valley and ND. Weak capping and the aforementioned seasonably moist airmass will favor isolated to scattered thunderstorms developing near the front and outflow late this afternoon into the evening. Diurnal steepening of low-level lapse rates may yield an isolated risk for localized severe gusts and perhaps marginally severe hail. This activity will likely diminish by mid evening owing to the loss of heating. ...Upper Midwest/Great Lakes... An upper trough centered near the IA/WI/MN/IL border will continue to slowly migrate east across WI/northern IL today. Similar to areas farther southwest over the south-central Plains, a seasonably moist will undergo some heating in areas void of thicker cloud cover and aid in 1000 J/kg MLCAPE developing over WI according to forecast soundings. Weak 0-6 km shear (i.e., < 20 kt) should temper updraft organization and limit storm intensity. Nonetheless, a couple of strong gusts or small hail may occur with the more vigorous storms this afternoon. ..Smith/Wendt.. 09/20/2025 Read more