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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... A large-scale trough will extend from the northern Rockies to the southern California coast on Monday morning. Within this broader trough, a closed low will develop off the California coast with a more progressive trough/low across the central Rockies. As mid-level flow strengthens across the southern/central High Plains, lee troughing will strengthen during the day on Monday. Guidance starts to diverge substantially with specific evolution of the mid-level pattern Monday, however, despite these differences the overall pattern of lee troughing across the central/southern High Plains remains. ...Central Plains into Oklahoma... Substantial low-level moisture advection ahead of the lee troughing across the southern/central High Plains will result in moderate to strong instability across Oklahoma and Kansas by Monday afternoon. As mid level flow around 40 knots overspreads this warm sector, hodographs will elongate and the environment will support organized storms including potential supercells. A strong EML is forecast across the warm sector which should suppress convection for much of the afternoon with gradual erosion of the inhibition by late afternoon. Initial storms will likely develop across southern Nebraska where cooler temperatures aloft and the synoptic warm front should provide ample forcing for thunderstorm development. Through the evening, expect additional development farther south as ascent erodes inhibition and permits storm development along the dryline. Steep mid-level lapse rates and potential supercell storm mode will support a threat for large hail initially. Expect storms to eventually congeal into one or more clusters with an increasing severe wind threat during the evening. A Slight risk may eventually be needed, but a displacement between the better forcing (farther north) and the better environment (farther south) precludes higher probabilities at this time. ..Bentley.. 09/20/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... A large-scale trough will extend from the northern Rockies to the southern California coast on Monday morning. Within this broader trough, a closed low will develop off the California coast with a more progressive trough/low across the central Rockies. As mid-level flow strengthens across the southern/central High Plains, lee troughing will strengthen during the day on Monday. Guidance starts to diverge substantially with specific evolution of the mid-level pattern Monday, however, despite these differences the overall pattern of lee troughing across the central/southern High Plains remains. ...Central Plains into Oklahoma... Substantial low-level moisture advection ahead of the lee troughing across the southern/central High Plains will result in moderate to strong instability across Oklahoma and Kansas by Monday afternoon. As mid level flow around 40 knots overspreads this warm sector, hodographs will elongate and the environment will support organized storms including potential supercells. A strong EML is forecast across the warm sector which should suppress convection for much of the afternoon with gradual erosion of the inhibition by late afternoon. Initial storms will likely develop across southern Nebraska where cooler temperatures aloft and the synoptic warm front should provide ample forcing for thunderstorm development. Through the evening, expect additional development farther south as ascent erodes inhibition and permits storm development along the dryline. Steep mid-level lapse rates and potential supercell storm mode will support a threat for large hail initially. Expect storms to eventually congeal into one or more clusters with an increasing severe wind threat during the evening. A Slight risk may eventually be needed, but a displacement between the better forcing (farther north) and the better environment (farther south) precludes higher probabilities at this time. ..Bentley.. 09/20/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... A large-scale trough will extend from the northern Rockies to the southern California coast on Monday morning. Within this broader trough, a closed low will develop off the California coast with a more progressive trough/low across the central Rockies. As mid-level flow strengthens across the southern/central High Plains, lee troughing will strengthen during the day on Monday. Guidance starts to diverge substantially with specific evolution of the mid-level pattern Monday, however, despite these differences the overall pattern of lee troughing across the central/southern High Plains remains. ...Central Plains into Oklahoma... Substantial low-level moisture advection ahead of the lee troughing across the southern/central High Plains will result in moderate to strong instability across Oklahoma and Kansas by Monday afternoon. As mid level flow around 40 knots overspreads this warm sector, hodographs will elongate and the environment will support organized storms including potential supercells. A strong EML is forecast across the warm sector which should suppress convection for much of the afternoon with gradual erosion of the inhibition by late afternoon. Initial storms will likely develop across southern Nebraska where cooler temperatures aloft and the synoptic warm front should provide ample forcing for thunderstorm development. Through the evening, expect additional development farther south as ascent erodes inhibition and permits storm development along the dryline. Steep mid-level lapse rates and potential supercell storm mode will support a threat for large hail initially. Expect storms to eventually congeal into one or more clusters with an increasing severe wind threat during the evening. A Slight risk may eventually be needed, but a displacement between the better forcing (farther north) and the better environment (farther south) precludes higher probabilities at this time. ..Bentley.. 09/20/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Sep 20 2025 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms will be possible on Monday across portions of the central and southern High Plains. ...Synopsis... A large-scale trough will extend from the northern Rockies to the southern California coast on Monday morning. Within this broader trough, a closed low will develop off the California coast with a more progressive trough/low across the central Rockies. As mid-level flow strengthens across the southern/central High Plains, lee troughing will strengthen during the day on Monday. Guidance starts to diverge substantially with specific evolution of the mid-level pattern Monday, however, despite these differences the overall pattern of lee troughing across the central/southern High Plains remains. ...Central Plains into Oklahoma... Substantial low-level moisture advection ahead of the lee troughing across the southern/central High Plains will result in moderate to strong instability across Oklahoma and Kansas by Monday afternoon. As mid level flow around 40 knots overspreads this warm sector, hodographs will elongate and the environment will support organized storms including potential supercells. A strong EML is forecast across the warm sector which should suppress convection for much of the afternoon with gradual erosion of the inhibition by late afternoon. Initial storms will likely develop across southern Nebraska where cooler temperatures aloft and the synoptic warm front should provide ample forcing for thunderstorm development. Through the evening, expect additional development farther south as ascent erodes inhibition and permits storm development along the dryline. Steep mid-level lapse rates and potential supercell storm mode will support a threat for large hail initially. Expect storms to eventually congeal into one or more clusters with an increasing severe wind threat during the evening. A Slight risk may eventually be needed, but a displacement between the better forcing (farther north) and the better environment (farther south) precludes higher probabilities at this time. ..Bentley.. 09/20/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO VALLEY AND GREAT LAKES... ...SUMMARY... A few strong to severe thunderstorms are possible across parts of the Ohio Valley and Great Lakes on Sunday. ...Synopsis... A mid-level trough will exist across the Upper Midwest on Sunday with multiple mid-level shortwave troughs extending within mostly zonal flow from the Mid-Atlantic to the central Rockies. A split flow pattern will exist along the West Coast with a trough across the Pacific Northwest and off the southern California coast. A surface low will exist off the East Coast. Otherwise, the surface pattern will be nebulous with weak lee troughing along the central and northern Plains. A weak surface low may be present across the western Great Lakes, ahead of the mid-level shortwave trough. ...Ohio Valley into the Great Lakes... Weak to moderate instability is forecast across the Ohio Valley and into the Great Lakes where mid 60s dewpoints will be present. Forecast soundings show minimal inhibition by mid afternoon with weak height falls across the warm sector. CAM guidance consistently shows scattered thunderstorm development Sunday afternoon/evening across the Ohio Valley/Great Lakes associated with a fast-moving mid-level shortwave trough. A belt of stronger mid-level flow (35 to 40 knots) is forecast to overspread the warm sector during the afternoon/evening. This will lead to increasing deep-layer shear which would aid in storm organization. A few strong to severe storms capable of damaging wind gusts are possible Sunday afternoon/evening. ...OK/KS Vicinity... A cluster of storms will likely be ongoing at the beginning of the period across Oklahoma. If sufficient destabilization can occur ahead of this cluster, a few strong storms could develop Sunday afternoon/evening. In addition, a weak mid-level shortwave trough (convectively enhanced by Day 1 convection across the central Rockies) may move across Kansas Sunday afternoon. However, given the low-amplitude nature of this wave and its dependence on Day 1 convection, considerable uncertainty in the amplitude and timing of this mid-level shortwave trough exists. This precludes the addition of severe weather probabilities at this time, despite a somewhat favorable thermodynamic environment and potentially favorable shear if mid-level flow enhancement overspreads the same area. ..Bentley.. 09/20/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO VALLEY AND GREAT LAKES... ...SUMMARY... A few strong to severe thunderstorms are possible across parts of the Ohio Valley and Great Lakes on Sunday. ...Synopsis... A mid-level trough will exist across the Upper Midwest on Sunday with multiple mid-level shortwave troughs extending within mostly zonal flow from the Mid-Atlantic to the central Rockies. A split flow pattern will exist along the West Coast with a trough across the Pacific Northwest and off the southern California coast. A surface low will exist off the East Coast. Otherwise, the surface pattern will be nebulous with weak lee troughing along the central and northern Plains. A weak surface low may be present across the western Great Lakes, ahead of the mid-level shortwave trough. ...Ohio Valley into the Great Lakes... Weak to moderate instability is forecast across the Ohio Valley and into the Great Lakes where mid 60s dewpoints will be present. Forecast soundings show minimal inhibition by mid afternoon with weak height falls across the warm sector. CAM guidance consistently shows scattered thunderstorm development Sunday afternoon/evening across the Ohio Valley/Great Lakes associated with a fast-moving mid-level shortwave trough. A belt of stronger mid-level flow (35 to 40 knots) is forecast to overspread the warm sector during the afternoon/evening. This will lead to increasing deep-layer shear which would aid in storm organization. A few strong to severe storms capable of damaging wind gusts are possible Sunday afternoon/evening. ...OK/KS Vicinity... A cluster of storms will likely be ongoing at the beginning of the period across Oklahoma. If sufficient destabilization can occur ahead of this cluster, a few strong storms could develop Sunday afternoon/evening. In addition, a weak mid-level shortwave trough (convectively enhanced by Day 1 convection across the central Rockies) may move across Kansas Sunday afternoon. However, given the low-amplitude nature of this wave and its dependence on Day 1 convection, considerable uncertainty in the amplitude and timing of this mid-level shortwave trough exists. This precludes the addition of severe weather probabilities at this time, despite a somewhat favorable thermodynamic environment and potentially favorable shear if mid-level flow enhancement overspreads the same area. ..Bentley.. 09/20/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO VALLEY AND GREAT LAKES... ...SUMMARY... A few strong to severe thunderstorms are possible across parts of the Ohio Valley and Great Lakes on Sunday. ...Synopsis... A mid-level trough will exist across the Upper Midwest on Sunday with multiple mid-level shortwave troughs extending within mostly zonal flow from the Mid-Atlantic to the central Rockies. A split flow pattern will exist along the West Coast with a trough across the Pacific Northwest and off the southern California coast. A surface low will exist off the East Coast. Otherwise, the surface pattern will be nebulous with weak lee troughing along the central and northern Plains. A weak surface low may be present across the western Great Lakes, ahead of the mid-level shortwave trough. ...Ohio Valley into the Great Lakes... Weak to moderate instability is forecast across the Ohio Valley and into the Great Lakes where mid 60s dewpoints will be present. Forecast soundings show minimal inhibition by mid afternoon with weak height falls across the warm sector. CAM guidance consistently shows scattered thunderstorm development Sunday afternoon/evening across the Ohio Valley/Great Lakes associated with a fast-moving mid-level shortwave trough. A belt of stronger mid-level flow (35 to 40 knots) is forecast to overspread the warm sector during the afternoon/evening. This will lead to increasing deep-layer shear which would aid in storm organization. A few strong to severe storms capable of damaging wind gusts are possible Sunday afternoon/evening. ...OK/KS Vicinity... A cluster of storms will likely be ongoing at the beginning of the period across Oklahoma. If sufficient destabilization can occur ahead of this cluster, a few strong storms could develop Sunday afternoon/evening. In addition, a weak mid-level shortwave trough (convectively enhanced by Day 1 convection across the central Rockies) may move across Kansas Sunday afternoon. However, given the low-amplitude nature of this wave and its dependence on Day 1 convection, considerable uncertainty in the amplitude and timing of this mid-level shortwave trough exists. This precludes the addition of severe weather probabilities at this time, despite a somewhat favorable thermodynamic environment and potentially favorable shear if mid-level flow enhancement overspreads the same area. ..Bentley.. 09/20/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO VALLEY AND GREAT LAKES... ...SUMMARY... A few strong to severe thunderstorms are possible across parts of the Ohio Valley and Great Lakes on Sunday. ...Synopsis... A mid-level trough will exist across the Upper Midwest on Sunday with multiple mid-level shortwave troughs extending within mostly zonal flow from the Mid-Atlantic to the central Rockies. A split flow pattern will exist along the West Coast with a trough across the Pacific Northwest and off the southern California coast. A surface low will exist off the East Coast. Otherwise, the surface pattern will be nebulous with weak lee troughing along the central and northern Plains. A weak surface low may be present across the western Great Lakes, ahead of the mid-level shortwave trough. ...Ohio Valley into the Great Lakes... Weak to moderate instability is forecast across the Ohio Valley and into the Great Lakes where mid 60s dewpoints will be present. Forecast soundings show minimal inhibition by mid afternoon with weak height falls across the warm sector. CAM guidance consistently shows scattered thunderstorm development Sunday afternoon/evening across the Ohio Valley/Great Lakes associated with a fast-moving mid-level shortwave trough. A belt of stronger mid-level flow (35 to 40 knots) is forecast to overspread the warm sector during the afternoon/evening. This will lead to increasing deep-layer shear which would aid in storm organization. A few strong to severe storms capable of damaging wind gusts are possible Sunday afternoon/evening. ...OK/KS Vicinity... A cluster of storms will likely be ongoing at the beginning of the period across Oklahoma. If sufficient destabilization can occur ahead of this cluster, a few strong storms could develop Sunday afternoon/evening. In addition, a weak mid-level shortwave trough (convectively enhanced by Day 1 convection across the central Rockies) may move across Kansas Sunday afternoon. However, given the low-amplitude nature of this wave and its dependence on Day 1 convection, considerable uncertainty in the amplitude and timing of this mid-level shortwave trough exists. This precludes the addition of severe weather probabilities at this time, despite a somewhat favorable thermodynamic environment and potentially favorable shear if mid-level flow enhancement overspreads the same area. ..Bentley.. 09/20/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... On Sunday-- weak surface winds, higher relative humidity, and high precipitable water content with forecast convection will generally suppress any fire-weather concerns across the continental U.S. ...North Cascades into the Columbia Basin... While conditions are forecast to be windier than Saturday, gusting as high as 15-20 MPH, relative humidity is forecast to remain above 30% due to persistent cloud cover and light precipitation. Though fuels are modestly receptive to wildfire ignition and spread, these conditions will limit the overall potential for that to occur. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... On Sunday-- weak surface winds, higher relative humidity, and high precipitable water content with forecast convection will generally suppress any fire-weather concerns across the continental U.S. ...North Cascades into the Columbia Basin... While conditions are forecast to be windier than Saturday, gusting as high as 15-20 MPH, relative humidity is forecast to remain above 30% due to persistent cloud cover and light precipitation. Though fuels are modestly receptive to wildfire ignition and spread, these conditions will limit the overall potential for that to occur. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... On Sunday-- weak surface winds, higher relative humidity, and high precipitable water content with forecast convection will generally suppress any fire-weather concerns across the continental U.S. ...North Cascades into the Columbia Basin... While conditions are forecast to be windier than Saturday, gusting as high as 15-20 MPH, relative humidity is forecast to remain above 30% due to persistent cloud cover and light precipitation. Though fuels are modestly receptive to wildfire ignition and spread, these conditions will limit the overall potential for that to occur. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... On Sunday-- weak surface winds, higher relative humidity, and high precipitable water content with forecast convection will generally suppress any fire-weather concerns across the continental U.S. ...North Cascades into the Columbia Basin... While conditions are forecast to be windier than Saturday, gusting as high as 15-20 MPH, relative humidity is forecast to remain above 30% due to persistent cloud cover and light precipitation. Though fuels are modestly receptive to wildfire ignition and spread, these conditions will limit the overall potential for that to occur. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... On Sunday-- weak surface winds, higher relative humidity, and high precipitable water content with forecast convection will generally suppress any fire-weather concerns across the continental U.S. ...North Cascades into the Columbia Basin... While conditions are forecast to be windier than Saturday, gusting as high as 15-20 MPH, relative humidity is forecast to remain above 30% due to persistent cloud cover and light precipitation. Though fuels are modestly receptive to wildfire ignition and spread, these conditions will limit the overall potential for that to occur. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 201200Z - 211200Z ...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. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 201200Z - 211200Z ...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. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 201200Z - 211200Z ...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. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 201200Z - 211200Z ...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. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Sat Sep 20 2025 Valid 201200Z - 211200Z ...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. ..Halbert.. 09/20/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1216 AM CDT Sat Sep 20 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO EVENING ACROSS PARTS OF THE SOUTH CENTRAL GREAT PLAINS... ...SUMMARY... Scattered strong thunderstorms may impact parts of the south central Great Plains late this afternoon and evening, accompanied by some risk for locally strong to severe wind gusts and perhaps some marginally severe hail. ...Discussion... In the northern mid-latitudes, flow across the Pacific appears likely to remain strong and zonal, with one significant short wave trough on the leading edge of this regime forecast to progress inland of the British Columbia and portions of Pacific Northwest coastal areas during this period. Downstream, models indicate that flow will remain more amplified across Canada into the northern Atlantic, with one significant trough and embedded cyclone slowly progressing offshore into the Labrador Sea/northwestern Atlantic vicinity. In the wake of this feature, the center of cool surface ridging is forecast shift from western Quebec into New England, with a ridge axis building south-southwestward to the lee of the Appalachians through much of the Atlantic Seaboard. In advance of the trough migrating inland of the Pacific, modest deepening of surface troughing appears possible as far south as the lee of the northern U.S. Rockies. However, much of the U.S. and adjacent interior southern Canada will generally remain under the influence of a weak split flow including larger-scale troughing in one branch across the northern Great Plains into Great Lakes/Ohio Valley, and troughing across the southern mid-/subtropical latitudes of the eastern Pacific and across the Southeast, within another branch. ...South Central Great Plains... Near the southwestern flank of the broad mid/upper troughing roughly centered across the mid/upper Mississippi Valley, it appears that boundary-layer destabilization may become characterized by moderately large CAPE in a pre-frontal corridor centered across the Texas Panhandle through northern Oklahoma by late this afternoon. As this maximizes, it appears that low-level convergence near modestly deepening surface troughing will support that initiation of scattered thunderstorm activity, perhaps aided by forcing for ascent associated with a subtle digging short wave perturbation. Although deep-layer wind fields and shear are forecast to be generally weak, forecast soundings characterized by relatively steep low-level lapse rates, including modestly deep boundary-layer mixing, appear conducive to localized strong to severe gusts and perhaps some marginally severe hail with stronger cells into early to mid evening. ..Kerr/Halbert.. 09/20/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1216 AM CDT Sat Sep 20 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON INTO EVENING ACROSS PARTS OF THE SOUTH CENTRAL GREAT PLAINS... ...SUMMARY... Scattered strong thunderstorms may impact parts of the south central Great Plains late this afternoon and evening, accompanied by some risk for locally strong to severe wind gusts and perhaps some marginally severe hail. ...Discussion... In the northern mid-latitudes, flow across the Pacific appears likely to remain strong and zonal, with one significant short wave trough on the leading edge of this regime forecast to progress inland of the British Columbia and portions of Pacific Northwest coastal areas during this period. Downstream, models indicate that flow will remain more amplified across Canada into the northern Atlantic, with one significant trough and embedded cyclone slowly progressing offshore into the Labrador Sea/northwestern Atlantic vicinity. In the wake of this feature, the center of cool surface ridging is forecast shift from western Quebec into New England, with a ridge axis building south-southwestward to the lee of the Appalachians through much of the Atlantic Seaboard. In advance of the trough migrating inland of the Pacific, modest deepening of surface troughing appears possible as far south as the lee of the northern U.S. Rockies. However, much of the U.S. and adjacent interior southern Canada will generally remain under the influence of a weak split flow including larger-scale troughing in one branch across the northern Great Plains into Great Lakes/Ohio Valley, and troughing across the southern mid-/subtropical latitudes of the eastern Pacific and across the Southeast, within another branch. ...South Central Great Plains... Near the southwestern flank of the broad mid/upper troughing roughly centered across the mid/upper Mississippi Valley, it appears that boundary-layer destabilization may become characterized by moderately large CAPE in a pre-frontal corridor centered across the Texas Panhandle through northern Oklahoma by late this afternoon. As this maximizes, it appears that low-level convergence near modestly deepening surface troughing will support that initiation of scattered thunderstorm activity, perhaps aided by forcing for ascent associated with a subtle digging short wave perturbation. Although deep-layer wind fields and shear are forecast to be generally weak, forecast soundings characterized by relatively steep low-level lapse rates, including modestly deep boundary-layer mixing, appear conducive to localized strong to severe gusts and perhaps some marginally severe hail with stronger cells into early to mid evening. ..Kerr/Halbert.. 09/20/2025 Read more