Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0135 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z Latest guidance continues to show the potential for isolated to widely scattered thunderstorms on Wednesday across northern CA into OR and adjacent portions of far northwest NV as an upper wave (currently along the central CA coast) lifts northward. Thunderstorms may be ongoing at the start of the forecast period before a second round develops by late afternoon. High-res guidance hints at cloud cover during the day that may hinder diurnal heating and destabilization to some degree, and PWAT values near 0.75 inches may support swaths of wetting rainfall with the more intense convection (as hinted by some CAM solutions). However, antecedent dry conditions within the lowest 2-3 km AGL should modulate rainfall totals to some degree, and will support the potential for dry lightning strikes - especially with weaker, more isolated storms. With dry fuels already in place and ongoing fires noted across the region, the potential for dry-lightning/thunderstorm driven fire concerns remains sufficiently high to maintain ongoing highlights despite some forecast concerns. ..Moore.. 09/02/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 02 2025/ ...Synopsis... As the upper-level low continues to shift northward through D2/Wednesday, the isolated dry thunderstorms chances will continue across northern California into central Oregon, southern Washington, and western Idaho. Storm motions will decrease but coverage and moisture may also decrease with more isolated lingering activity expected. An isolated dry thunderstorm area was maintained with this outlook to cover this potential. ...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 0135 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z Latest guidance continues to show the potential for isolated to widely scattered thunderstorms on Wednesday across northern CA into OR and adjacent portions of far northwest NV as an upper wave (currently along the central CA coast) lifts northward. Thunderstorms may be ongoing at the start of the forecast period before a second round develops by late afternoon. High-res guidance hints at cloud cover during the day that may hinder diurnal heating and destabilization to some degree, and PWAT values near 0.75 inches may support swaths of wetting rainfall with the more intense convection (as hinted by some CAM solutions). However, antecedent dry conditions within the lowest 2-3 km AGL should modulate rainfall totals to some degree, and will support the potential for dry lightning strikes - especially with weaker, more isolated storms. With dry fuels already in place and ongoing fires noted across the region, the potential for dry-lightning/thunderstorm driven fire concerns remains sufficiently high to maintain ongoing highlights despite some forecast concerns. ..Moore.. 09/02/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 02 2025/ ...Synopsis... As the upper-level low continues to shift northward through D2/Wednesday, the isolated dry thunderstorms chances will continue across northern California into central Oregon, southern Washington, and western Idaho. Storm motions will decrease but coverage and moisture may also decrease with more isolated lingering activity expected. An isolated dry thunderstorm area was maintained with this outlook to cover this potential. ...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 0135 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z Latest guidance continues to show the potential for isolated to widely scattered thunderstorms on Wednesday across northern CA into OR and adjacent portions of far northwest NV as an upper wave (currently along the central CA coast) lifts northward. Thunderstorms may be ongoing at the start of the forecast period before a second round develops by late afternoon. High-res guidance hints at cloud cover during the day that may hinder diurnal heating and destabilization to some degree, and PWAT values near 0.75 inches may support swaths of wetting rainfall with the more intense convection (as hinted by some CAM solutions). However, antecedent dry conditions within the lowest 2-3 km AGL should modulate rainfall totals to some degree, and will support the potential for dry lightning strikes - especially with weaker, more isolated storms. With dry fuels already in place and ongoing fires noted across the region, the potential for dry-lightning/thunderstorm driven fire concerns remains sufficiently high to maintain ongoing highlights despite some forecast concerns. ..Moore.. 09/02/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 02 2025/ ...Synopsis... As the upper-level low continues to shift northward through D2/Wednesday, the isolated dry thunderstorms chances will continue across northern California into central Oregon, southern Washington, and western Idaho. Storm motions will decrease but coverage and moisture may also decrease with more isolated lingering activity expected. An isolated dry thunderstorm area was maintained with this outlook to cover this potential. ...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 0135 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z Latest guidance continues to show the potential for isolated to widely scattered thunderstorms on Wednesday across northern CA into OR and adjacent portions of far northwest NV as an upper wave (currently along the central CA coast) lifts northward. Thunderstorms may be ongoing at the start of the forecast period before a second round develops by late afternoon. High-res guidance hints at cloud cover during the day that may hinder diurnal heating and destabilization to some degree, and PWAT values near 0.75 inches may support swaths of wetting rainfall with the more intense convection (as hinted by some CAM solutions). However, antecedent dry conditions within the lowest 2-3 km AGL should modulate rainfall totals to some degree, and will support the potential for dry lightning strikes - especially with weaker, more isolated storms. With dry fuels already in place and ongoing fires noted across the region, the potential for dry-lightning/thunderstorm driven fire concerns remains sufficiently high to maintain ongoing highlights despite some forecast concerns. ..Moore.. 09/02/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 02 2025/ ...Synopsis... As the upper-level low continues to shift northward through D2/Wednesday, the isolated dry thunderstorms chances will continue across northern California into central Oregon, southern Washington, and western Idaho. Storm motions will decrease but coverage and moisture may also decrease with more isolated lingering activity expected. An isolated dry thunderstorm area was maintained with this outlook to cover this potential. ...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 0135 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z Latest guidance continues to show the potential for isolated to widely scattered thunderstorms on Wednesday across northern CA into OR and adjacent portions of far northwest NV as an upper wave (currently along the central CA coast) lifts northward. Thunderstorms may be ongoing at the start of the forecast period before a second round develops by late afternoon. High-res guidance hints at cloud cover during the day that may hinder diurnal heating and destabilization to some degree, and PWAT values near 0.75 inches may support swaths of wetting rainfall with the more intense convection (as hinted by some CAM solutions). However, antecedent dry conditions within the lowest 2-3 km AGL should modulate rainfall totals to some degree, and will support the potential for dry lightning strikes - especially with weaker, more isolated storms. With dry fuels already in place and ongoing fires noted across the region, the potential for dry-lightning/thunderstorm driven fire concerns remains sufficiently high to maintain ongoing highlights despite some forecast concerns. ..Moore.. 09/02/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 02 2025/ ...Synopsis... As the upper-level low continues to shift northward through D2/Wednesday, the isolated dry thunderstorms chances will continue across northern California into central Oregon, southern Washington, and western Idaho. Storm motions will decrease but coverage and moisture may also decrease with more isolated lingering activity expected. An isolated dry thunderstorm area was maintained with this outlook to cover this potential. ...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 0135 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z Latest guidance continues to show the potential for isolated to widely scattered thunderstorms on Wednesday across northern CA into OR and adjacent portions of far northwest NV as an upper wave (currently along the central CA coast) lifts northward. Thunderstorms may be ongoing at the start of the forecast period before a second round develops by late afternoon. High-res guidance hints at cloud cover during the day that may hinder diurnal heating and destabilization to some degree, and PWAT values near 0.75 inches may support swaths of wetting rainfall with the more intense convection (as hinted by some CAM solutions). However, antecedent dry conditions within the lowest 2-3 km AGL should modulate rainfall totals to some degree, and will support the potential for dry lightning strikes - especially with weaker, more isolated storms. With dry fuels already in place and ongoing fires noted across the region, the potential for dry-lightning/thunderstorm driven fire concerns remains sufficiently high to maintain ongoing highlights despite some forecast concerns. ..Moore.. 09/02/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Tue Sep 02 2025/ ...Synopsis... As the upper-level low continues to shift northward through D2/Wednesday, the isolated dry thunderstorms chances will continue across northern California into central Oregon, southern Washington, and western Idaho. Storm motions will decrease but coverage and moisture may also decrease with more isolated lingering activity expected. An isolated dry thunderstorm area was maintained with this outlook to cover this potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY AFTERNOON INTO EVENING ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO WEST CENTRAL MISSOURI... ...SUMMARY... Scattered strong thunderstorms will impact parts of the central Great Plains into Missouri Ozarks late Wednesday afternoon and evening, accompanied primarily by a risk for severe hail and potential for damaging wind gusts. ...Discussion... The large-scale mid/upper flow regime remains amplified across the eastern mid-latitude Pacific through North America, with little appreciable change forecast through this period. Troughing will be maintained east of the Canadian/U.S. Rockies, as far south as the Gulf Basin into southwestern Atlantic, reinforced by a pair of vigorous digging short wave perturbations emerging from the northern mid- to Arctic latitudes of northwestern Canada. The lead impulse is forecast to be in the process of digging across the international border through portions of the northern U.S. Great Plains and Upper Midwest by 12Z Wednesday. Models indicate that this will contribute to notable lower/mid-tropospheric cyclogenesis near/north of Lake Superior, toward the James Bay vicinity, through daybreak Thursday, as the trailing perturbation digs southeast of the Northwest Territories through eastern Canadian Prairies. While one initial weakening frontal zone (and associated plume of seasonably high moisture content) lingers across the central Gulf through southern Florida Peninsula/Straits vicinity, an initial reinforcing intrusion of cooler/drier air is forecast to surge into the Ohio Valley and through much of the central Great Plains by late Wednesday night. Another will begin nosing southward to the lee of the Canadian toward northern U.S. Rockies. ...Central Great Plains into Missouri Ozarks... Near the southwestern periphery of strengthening northwesterly mid-level flow (including 40+ kt around 500 mb), models continue to indicate that a plume of steepening lower/mid-tropospheric lapse rates will advect across the central Great Plains toward adjacent lower Missouri Valley vicinity during the day. Beneath this regime, it appears that residual boundary-layer moisture will remain sufficient to support the development of moderate potential instability, generally becoming focused in a corridor along/ahead of the southward advancing front and pre-frontal surface troughing by late afternoon. Uncertainties do linger due to continuing spread in the model output, particularly with regard to the degree of mid/upper forcing for ascent overspreading the region during the peak late afternoon instability, to the southwest of the primary digging mid-level trough/evolving low near the upper Great Lakes. With sufficient lift to overcome mid-level inhibition, the sheared environment will likely be conditionally conducive to organized severe convection. It is possible that this could be limited to one or two supercells and/or a small upscale growing cluster. However, this activity could become capable of producing large hail and potentially damaging wind gusts for at least a few hours late Wednesday afternoon into evening. ..Kerr.. 09/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Tue Sep 02 2025 Valid 021630Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA INTO SOUTHERN/CENTRAL MINNESOTA AND FAR NORTHWESTERN WISCONSIN... ...SUMMARY... Thunderstorms capable of producing isolated severe wind gusts and marginally severe hail will be possible this afternoon and evening across parts of the northern Plains and Upper Midwest. ...Northern Plains/Upper Midwest... An upper trough over central Canada late this morning will dig southeastward towards the Upper Midwest/Lake Superior vicinity through the period. Showers and weak thunderstorms are ongoing over parts of central MN, aided by a remnant MCV over northern MN. This activity is forecast to further weaken this afternoon, with a residual outflow boundary arcing from southern MN west-northwestward towards the SD/MN border by mid afternoon. A cold front over ND will continue to advance southeastward into an adequately moist low-level airmass, with surface dewpoints generally in the lower to mid 60s. Filtered daytime heating away from this morning's convective cloud debris, along with modestly steepened mid-level lapse rates (reference 12Z ABR sounding), should aid in weak to locally moderate instability (MLCAPE around 1000-2000 J/kg) developing ahead of the front by mid to late afternoon. Latest model guidance remains consistent in showing isolated to scattered thunderstorms developing across roughly the eastern third of SD into central MN this afternoon along/near the cold front. There is considerable uncertainty regarding the degree of instability that will develop and related thunderstorm intensity given the widespread cloud cover in south-central MN. The stronger mid/upper-level flow associated with the upper trough over Canada will likely lag behind the surface front to some extent. This should limit effective bulk shear magnitudes (up to 20-30 kt). Even so, modestly organized multicells associated with isolated severe wind gusts and marginally severe hail appear possible, before this activity eventually subsides this evening with the loss of daytime heating. The Marginal Risk has been adjusted to account for the latest observational/short-term guidance trends. ...Lower Colorado River Valley... Compared to yesterday, modestly enhanced mid-level flow should trend more south-southeasterly today as a weak shortwave trough lifts northward from Baja California into the lower CO River Valley. Associated/ongoing showers and thunderstorms across southern CA should generally remain sub-severe through the morning as they track northwestward. In the wake of this activity, there is a fair amount of uncertainty regarding destabilization potential given scattered to widespread cloudiness over much of the lower CO River Valley. Wherever cloud breaks and heating can occur, steepening low-level lapse rates may support strong/gusty winds with any convection that can develop. Still, the potential for a focused area of severe gusts appears too low to include any probabilities at this time. ..Gleason/Lyons.. 09/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Tue Sep 02 2025 Valid 021630Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA INTO SOUTHERN/CENTRAL MINNESOTA AND FAR NORTHWESTERN WISCONSIN... ...SUMMARY... Thunderstorms capable of producing isolated severe wind gusts and marginally severe hail will be possible this afternoon and evening across parts of the northern Plains and Upper Midwest. ...Northern Plains/Upper Midwest... An upper trough over central Canada late this morning will dig southeastward towards the Upper Midwest/Lake Superior vicinity through the period. Showers and weak thunderstorms are ongoing over parts of central MN, aided by a remnant MCV over northern MN. This activity is forecast to further weaken this afternoon, with a residual outflow boundary arcing from southern MN west-northwestward towards the SD/MN border by mid afternoon. A cold front over ND will continue to advance southeastward into an adequately moist low-level airmass, with surface dewpoints generally in the lower to mid 60s. Filtered daytime heating away from this morning's convective cloud debris, along with modestly steepened mid-level lapse rates (reference 12Z ABR sounding), should aid in weak to locally moderate instability (MLCAPE around 1000-2000 J/kg) developing ahead of the front by mid to late afternoon. Latest model guidance remains consistent in showing isolated to scattered thunderstorms developing across roughly the eastern third of SD into central MN this afternoon along/near the cold front. There is considerable uncertainty regarding the degree of instability that will develop and related thunderstorm intensity given the widespread cloud cover in south-central MN. The stronger mid/upper-level flow associated with the upper trough over Canada will likely lag behind the surface front to some extent. This should limit effective bulk shear magnitudes (up to 20-30 kt). Even so, modestly organized multicells associated with isolated severe wind gusts and marginally severe hail appear possible, before this activity eventually subsides this evening with the loss of daytime heating. The Marginal Risk has been adjusted to account for the latest observational/short-term guidance trends. ...Lower Colorado River Valley... Compared to yesterday, modestly enhanced mid-level flow should trend more south-southeasterly today as a weak shortwave trough lifts northward from Baja California into the lower CO River Valley. Associated/ongoing showers and thunderstorms across southern CA should generally remain sub-severe through the morning as they track northwestward. In the wake of this activity, there is a fair amount of uncertainty regarding destabilization potential given scattered to widespread cloudiness over much of the lower CO River Valley. Wherever cloud breaks and heating can occur, steepening low-level lapse rates may support strong/gusty winds with any convection that can develop. Still, the potential for a focused area of severe gusts appears too low to include any probabilities at this time. ..Gleason/Lyons.. 09/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Tue Sep 02 2025 Valid 021630Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA INTO SOUTHERN/CENTRAL MINNESOTA AND FAR NORTHWESTERN WISCONSIN... ...SUMMARY... Thunderstorms capable of producing isolated severe wind gusts and marginally severe hail will be possible this afternoon and evening across parts of the northern Plains and Upper Midwest. ...Northern Plains/Upper Midwest... An upper trough over central Canada late this morning will dig southeastward towards the Upper Midwest/Lake Superior vicinity through the period. Showers and weak thunderstorms are ongoing over parts of central MN, aided by a remnant MCV over northern MN. This activity is forecast to further weaken this afternoon, with a residual outflow boundary arcing from southern MN west-northwestward towards the SD/MN border by mid afternoon. A cold front over ND will continue to advance southeastward into an adequately moist low-level airmass, with surface dewpoints generally in the lower to mid 60s. Filtered daytime heating away from this morning's convective cloud debris, along with modestly steepened mid-level lapse rates (reference 12Z ABR sounding), should aid in weak to locally moderate instability (MLCAPE around 1000-2000 J/kg) developing ahead of the front by mid to late afternoon. Latest model guidance remains consistent in showing isolated to scattered thunderstorms developing across roughly the eastern third of SD into central MN this afternoon along/near the cold front. There is considerable uncertainty regarding the degree of instability that will develop and related thunderstorm intensity given the widespread cloud cover in south-central MN. The stronger mid/upper-level flow associated with the upper trough over Canada will likely lag behind the surface front to some extent. This should limit effective bulk shear magnitudes (up to 20-30 kt). Even so, modestly organized multicells associated with isolated severe wind gusts and marginally severe hail appear possible, before this activity eventually subsides this evening with the loss of daytime heating. The Marginal Risk has been adjusted to account for the latest observational/short-term guidance trends. ...Lower Colorado River Valley... Compared to yesterday, modestly enhanced mid-level flow should trend more south-southeasterly today as a weak shortwave trough lifts northward from Baja California into the lower CO River Valley. Associated/ongoing showers and thunderstorms across southern CA should generally remain sub-severe through the morning as they track northwestward. In the wake of this activity, there is a fair amount of uncertainty regarding destabilization potential given scattered to widespread cloudiness over much of the lower CO River Valley. Wherever cloud breaks and heating can occur, steepening low-level lapse rates may support strong/gusty winds with any convection that can develop. Still, the potential for a focused area of severe gusts appears too low to include any probabilities at this time. ..Gleason/Lyons.. 09/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Tue Sep 02 2025 Valid 021630Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA INTO SOUTHERN/CENTRAL MINNESOTA AND FAR NORTHWESTERN WISCONSIN... ...SUMMARY... Thunderstorms capable of producing isolated severe wind gusts and marginally severe hail will be possible this afternoon and evening across parts of the northern Plains and Upper Midwest. ...Northern Plains/Upper Midwest... An upper trough over central Canada late this morning will dig southeastward towards the Upper Midwest/Lake Superior vicinity through the period. Showers and weak thunderstorms are ongoing over parts of central MN, aided by a remnant MCV over northern MN. This activity is forecast to further weaken this afternoon, with a residual outflow boundary arcing from southern MN west-northwestward towards the SD/MN border by mid afternoon. A cold front over ND will continue to advance southeastward into an adequately moist low-level airmass, with surface dewpoints generally in the lower to mid 60s. Filtered daytime heating away from this morning's convective cloud debris, along with modestly steepened mid-level lapse rates (reference 12Z ABR sounding), should aid in weak to locally moderate instability (MLCAPE around 1000-2000 J/kg) developing ahead of the front by mid to late afternoon. Latest model guidance remains consistent in showing isolated to scattered thunderstorms developing across roughly the eastern third of SD into central MN this afternoon along/near the cold front. There is considerable uncertainty regarding the degree of instability that will develop and related thunderstorm intensity given the widespread cloud cover in south-central MN. The stronger mid/upper-level flow associated with the upper trough over Canada will likely lag behind the surface front to some extent. This should limit effective bulk shear magnitudes (up to 20-30 kt). Even so, modestly organized multicells associated with isolated severe wind gusts and marginally severe hail appear possible, before this activity eventually subsides this evening with the loss of daytime heating. The Marginal Risk has been adjusted to account for the latest observational/short-term guidance trends. ...Lower Colorado River Valley... Compared to yesterday, modestly enhanced mid-level flow should trend more south-southeasterly today as a weak shortwave trough lifts northward from Baja California into the lower CO River Valley. Associated/ongoing showers and thunderstorms across southern CA should generally remain sub-severe through the morning as they track northwestward. In the wake of this activity, there is a fair amount of uncertainty regarding destabilization potential given scattered to widespread cloudiness over much of the lower CO River Valley. Wherever cloud breaks and heating can occur, steepening low-level lapse rates may support strong/gusty winds with any convection that can develop. Still, the potential for a focused area of severe gusts appears too low to include any probabilities at this time. ..Gleason/Lyons.. 09/02/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Tue Sep 02 2025 Valid 021630Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN SOUTH DAKOTA INTO SOUTHERN/CENTRAL MINNESOTA AND FAR NORTHWESTERN WISCONSIN... ...SUMMARY... Thunderstorms capable of producing isolated severe wind gusts and marginally severe hail will be possible this afternoon and evening across parts of the northern Plains and Upper Midwest. ...Northern Plains/Upper Midwest... An upper trough over central Canada late this morning will dig southeastward towards the Upper Midwest/Lake Superior vicinity through the period. Showers and weak thunderstorms are ongoing over parts of central MN, aided by a remnant MCV over northern MN. This activity is forecast to further weaken this afternoon, with a residual outflow boundary arcing from southern MN west-northwestward towards the SD/MN border by mid afternoon. A cold front over ND will continue to advance southeastward into an adequately moist low-level airmass, with surface dewpoints generally in the lower to mid 60s. Filtered daytime heating away from this morning's convective cloud debris, along with modestly steepened mid-level lapse rates (reference 12Z ABR sounding), should aid in weak to locally moderate instability (MLCAPE around 1000-2000 J/kg) developing ahead of the front by mid to late afternoon. Latest model guidance remains consistent in showing isolated to scattered thunderstorms developing across roughly the eastern third of SD into central MN this afternoon along/near the cold front. There is considerable uncertainty regarding the degree of instability that will develop and related thunderstorm intensity given the widespread cloud cover in south-central MN. The stronger mid/upper-level flow associated with the upper trough over Canada will likely lag behind the surface front to some extent. This should limit effective bulk shear magnitudes (up to 20-30 kt). Even so, modestly organized multicells associated with isolated severe wind gusts and marginally severe hail appear possible, before this activity eventually subsides this evening with the loss of daytime heating. The Marginal Risk has been adjusted to account for the latest observational/short-term guidance trends. ...Lower Colorado River Valley... Compared to yesterday, modestly enhanced mid-level flow should trend more south-southeasterly today as a weak shortwave trough lifts northward from Baja California into the lower CO River Valley. Associated/ongoing showers and thunderstorms across southern CA should generally remain sub-severe through the morning as they track northwestward. In the wake of this activity, there is a fair amount of uncertainty regarding destabilization potential given scattered to widespread cloudiness over much of the lower CO River Valley. Wherever cloud breaks and heating can occur, steepening low-level lapse rates may support strong/gusty winds with any convection that can develop. Still, the potential for a focused area of severe gusts appears too low to include any probabilities at this time. ..Gleason/Lyons.. 09/02/2025 Read more