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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Tue Sep 02 2025 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL APPALACHIANS... ...SUMMARY... A few strong to potentially severe gusts may accompany a band of thunderstorms across parts of the central Appalachians on Thursday. ...Synopsis... Broad cyclonic flow will overspread much of the central and eastern CONUS on Thursday. Through the period, a mid-level impulse will pivot around the broader cyclonic flow into Quebec while an even more potent embedded mid-level trough rapidly amplifies over the Midwest. As a result, a surface cold front will rapidly surge eastward over the Appalachians and impinge on the East Coast, where seasonal low-level moisture will be in place to support an extensive band of thunderstorms. Given overlapping buoyancy and vertical wind shear, a few storms may be strong to severe. ...Central Appalachians... The cold front will surge to the east during the late morning into early afternoon hours, encountering low 60s F dewpoints over the central Appalachians. Tropospheric lapse rates should be poor, yielding thin MLCAPE profiles in the 500-1000 J/kg range. The lack of stronger buoyancy should limit the severe threat to a degree. Nonetheless, strengthening and veering of the 850-500 mb flow with height will encourage curved/elongated hodographs with 40-50 kts of effective bulk shear. A broken squall line should develop ahead of the cold front, perhaps with transient rotating cells, capable of mainly damaging gusts, warranting the introduction of Category 1/Marginal risk probabilities. ..Squitieri.. 09/02/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Tue Sep 02 2025 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL APPALACHIANS... ...SUMMARY... A few strong to potentially severe gusts may accompany a band of thunderstorms across parts of the central Appalachians on Thursday. ...Synopsis... Broad cyclonic flow will overspread much of the central and eastern CONUS on Thursday. Through the period, a mid-level impulse will pivot around the broader cyclonic flow into Quebec while an even more potent embedded mid-level trough rapidly amplifies over the Midwest. As a result, a surface cold front will rapidly surge eastward over the Appalachians and impinge on the East Coast, where seasonal low-level moisture will be in place to support an extensive band of thunderstorms. Given overlapping buoyancy and vertical wind shear, a few storms may be strong to severe. ...Central Appalachians... The cold front will surge to the east during the late morning into early afternoon hours, encountering low 60s F dewpoints over the central Appalachians. Tropospheric lapse rates should be poor, yielding thin MLCAPE profiles in the 500-1000 J/kg range. The lack of stronger buoyancy should limit the severe threat to a degree. Nonetheless, strengthening and veering of the 850-500 mb flow with height will encourage curved/elongated hodographs with 40-50 kts of effective bulk shear. A broken squall line should develop ahead of the cold front, perhaps with transient rotating cells, capable of mainly damaging gusts, warranting the introduction of Category 1/Marginal risk probabilities. ..Squitieri.. 09/02/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...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. ..Thornton.. 09/02/2025 ...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 0156 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...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. ..Thornton.. 09/02/2025 ...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 0156 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...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. ..Thornton.. 09/02/2025 ...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 0156 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...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. ..Thornton.. 09/02/2025 ...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 0156 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...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. ..Thornton.. 09/02/2025 ...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 0155 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...Synopsis... A weak upper-level low will move northward across northern California into the Pacific Northwest today through D2/Wednesday, with increases in moisture and forcing leading to thunderstorm development. Precipitable water values will approach 0.60-0.90", decreasing with eastward extent across eastern Oregon/western Nevada. Faster storm motions around 15-20 kts will likely lead to a mix of wet/dry thunderstorms. New starts will be possible where little to no precipitation occurs, with ERCs around the 80th-90th percentile across portions of these regions. An isolated dry thunderstorm area was maintained with this outlook across portions of northern California into western Nevada an northward into central Oregon. ..Thornton.. 09/02/2025 ...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 0155 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...Synopsis... A weak upper-level low will move northward across northern California into the Pacific Northwest today through D2/Wednesday, with increases in moisture and forcing leading to thunderstorm development. Precipitable water values will approach 0.60-0.90", decreasing with eastward extent across eastern Oregon/western Nevada. Faster storm motions around 15-20 kts will likely lead to a mix of wet/dry thunderstorms. New starts will be possible where little to no precipitation occurs, with ERCs around the 80th-90th percentile across portions of these regions. An isolated dry thunderstorm area was maintained with this outlook across portions of northern California into western Nevada an northward into central Oregon. ..Thornton.. 09/02/2025 ...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 0155 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...Synopsis... A weak upper-level low will move northward across northern California into the Pacific Northwest today through D2/Wednesday, with increases in moisture and forcing leading to thunderstorm development. Precipitable water values will approach 0.60-0.90", decreasing with eastward extent across eastern Oregon/western Nevada. Faster storm motions around 15-20 kts will likely lead to a mix of wet/dry thunderstorms. New starts will be possible where little to no precipitation occurs, with ERCs around the 80th-90th percentile across portions of these regions. An isolated dry thunderstorm area was maintained with this outlook across portions of northern California into western Nevada an northward into central Oregon. ..Thornton.. 09/02/2025 ...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 0155 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...Synopsis... A weak upper-level low will move northward across northern California into the Pacific Northwest today through D2/Wednesday, with increases in moisture and forcing leading to thunderstorm development. Precipitable water values will approach 0.60-0.90", decreasing with eastward extent across eastern Oregon/western Nevada. Faster storm motions around 15-20 kts will likely lead to a mix of wet/dry thunderstorms. New starts will be possible where little to no precipitation occurs, with ERCs around the 80th-90th percentile across portions of these regions. An isolated dry thunderstorm area was maintained with this outlook across portions of northern California into western Nevada an northward into central Oregon. ..Thornton.. 09/02/2025 ...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 0155 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...Synopsis... A weak upper-level low will move northward across northern California into the Pacific Northwest today through D2/Wednesday, with increases in moisture and forcing leading to thunderstorm development. Precipitable water values will approach 0.60-0.90", decreasing with eastward extent across eastern Oregon/western Nevada. Faster storm motions around 15-20 kts will likely lead to a mix of wet/dry thunderstorms. New starts will be possible where little to no precipitation occurs, with ERCs around the 80th-90th percentile across portions of these regions. An isolated dry thunderstorm area was maintained with this outlook across portions of northern California into western Nevada an northward into central Oregon. ..Thornton.. 09/02/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL INTO EASTERN KANSAS... ...SUMMARY... A risk of severe storms exists for portions of the central Plains. Severe wind and hail are the primary threats, and an instance or two of 2+ inch diameter hail is also possible. ...Synopsis... A mid-level trough will rapidly amplify across the MS Valley region while upper ridging persists over the Interior West tomorrow (Wednesday). The central U.S. will be located within a deep-layer northwesterly flow regime. A surface cold front will surge southward across the central Plains, acting as a low-level lifting source (via convergence) for seasonal low-level moisture over the region. At least scattered strong thunderstorms are expected ahead of the cold front during the afternoon. Given strong flow/shear and colder temperatures aloft overspreading the pre-frontal airmass with the passage of an embedded impulse, some of the storms are expected to be severe. ...Central Plains... As the surface cold front approaches central and eastern KS from the north, surface temperatures may exceed 80 F amid mid to upper 60s F dewpoints. With 7-8 C/km mid-level lapse rates overspreading this airmass, MLCAPE may reach as high as 2500 J/kg in spots. Kinematically speaking, veering low-level flow, overspread by strong northwesterlies will yield curved and elongated hodographs with 40-50 kts of effective bulk shear. The stronger storms are expected to become supercells, accompanied by severe wind and hail. There are some indications that a couple of stronger, sustained supercells may develop across eastern KS during the late afternoon to early evening hours. Given both the vertical shear profiles and colder temperatures aloft, a couple instances of 2+ inch hail and perhaps a tornado are possible. ..Squitieri.. 09/02/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL INTO EASTERN KANSAS... ...SUMMARY... A risk of severe storms exists for portions of the central Plains. Severe wind and hail are the primary threats, and an instance or two of 2+ inch diameter hail is also possible. ...Synopsis... A mid-level trough will rapidly amplify across the MS Valley region while upper ridging persists over the Interior West tomorrow (Wednesday). The central U.S. will be located within a deep-layer northwesterly flow regime. A surface cold front will surge southward across the central Plains, acting as a low-level lifting source (via convergence) for seasonal low-level moisture over the region. At least scattered strong thunderstorms are expected ahead of the cold front during the afternoon. Given strong flow/shear and colder temperatures aloft overspreading the pre-frontal airmass with the passage of an embedded impulse, some of the storms are expected to be severe. ...Central Plains... As the surface cold front approaches central and eastern KS from the north, surface temperatures may exceed 80 F amid mid to upper 60s F dewpoints. With 7-8 C/km mid-level lapse rates overspreading this airmass, MLCAPE may reach as high as 2500 J/kg in spots. Kinematically speaking, veering low-level flow, overspread by strong northwesterlies will yield curved and elongated hodographs with 40-50 kts of effective bulk shear. The stronger storms are expected to become supercells, accompanied by severe wind and hail. There are some indications that a couple of stronger, sustained supercells may develop across eastern KS during the late afternoon to early evening hours. Given both the vertical shear profiles and colder temperatures aloft, a couple instances of 2+ inch hail and perhaps a tornado are possible. ..Squitieri.. 09/02/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL INTO EASTERN KANSAS... ...SUMMARY... A risk of severe storms exists for portions of the central Plains. Severe wind and hail are the primary threats, and an instance or two of 2+ inch diameter hail is also possible. ...Synopsis... A mid-level trough will rapidly amplify across the MS Valley region while upper ridging persists over the Interior West tomorrow (Wednesday). The central U.S. will be located within a deep-layer northwesterly flow regime. A surface cold front will surge southward across the central Plains, acting as a low-level lifting source (via convergence) for seasonal low-level moisture over the region. At least scattered strong thunderstorms are expected ahead of the cold front during the afternoon. Given strong flow/shear and colder temperatures aloft overspreading the pre-frontal airmass with the passage of an embedded impulse, some of the storms are expected to be severe. ...Central Plains... As the surface cold front approaches central and eastern KS from the north, surface temperatures may exceed 80 F amid mid to upper 60s F dewpoints. With 7-8 C/km mid-level lapse rates overspreading this airmass, MLCAPE may reach as high as 2500 J/kg in spots. Kinematically speaking, veering low-level flow, overspread by strong northwesterlies will yield curved and elongated hodographs with 40-50 kts of effective bulk shear. The stronger storms are expected to become supercells, accompanied by severe wind and hail. There are some indications that a couple of stronger, sustained supercells may develop across eastern KS during the late afternoon to early evening hours. Given both the vertical shear profiles and colder temperatures aloft, a couple instances of 2+ inch hail and perhaps a tornado are possible. ..Squitieri.. 09/02/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL INTO EASTERN KANSAS... ...SUMMARY... A risk of severe storms exists for portions of the central Plains. Severe wind and hail are the primary threats, and an instance or two of 2+ inch diameter hail is also possible. ...Synopsis... A mid-level trough will rapidly amplify across the MS Valley region while upper ridging persists over the Interior West tomorrow (Wednesday). The central U.S. will be located within a deep-layer northwesterly flow regime. A surface cold front will surge southward across the central Plains, acting as a low-level lifting source (via convergence) for seasonal low-level moisture over the region. At least scattered strong thunderstorms are expected ahead of the cold front during the afternoon. Given strong flow/shear and colder temperatures aloft overspreading the pre-frontal airmass with the passage of an embedded impulse, some of the storms are expected to be severe. ...Central Plains... As the surface cold front approaches central and eastern KS from the north, surface temperatures may exceed 80 F amid mid to upper 60s F dewpoints. With 7-8 C/km mid-level lapse rates overspreading this airmass, MLCAPE may reach as high as 2500 J/kg in spots. Kinematically speaking, veering low-level flow, overspread by strong northwesterlies will yield curved and elongated hodographs with 40-50 kts of effective bulk shear. The stronger storms are expected to become supercells, accompanied by severe wind and hail. There are some indications that a couple of stronger, sustained supercells may develop across eastern KS during the late afternoon to early evening hours. Given both the vertical shear profiles and colder temperatures aloft, a couple instances of 2+ inch hail and perhaps a tornado are possible. ..Squitieri.. 09/02/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Sep 02 2025 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF CENTRAL INTO EASTERN KANSAS... ...SUMMARY... A risk of severe storms exists for portions of the central Plains. Severe wind and hail are the primary threats, and an instance or two of 2+ inch diameter hail is also possible. ...Synopsis... A mid-level trough will rapidly amplify across the MS Valley region while upper ridging persists over the Interior West tomorrow (Wednesday). The central U.S. will be located within a deep-layer northwesterly flow regime. A surface cold front will surge southward across the central Plains, acting as a low-level lifting source (via convergence) for seasonal low-level moisture over the region. At least scattered strong thunderstorms are expected ahead of the cold front during the afternoon. Given strong flow/shear and colder temperatures aloft overspreading the pre-frontal airmass with the passage of an embedded impulse, some of the storms are expected to be severe. ...Central Plains... As the surface cold front approaches central and eastern KS from the north, surface temperatures may exceed 80 F amid mid to upper 60s F dewpoints. With 7-8 C/km mid-level lapse rates overspreading this airmass, MLCAPE may reach as high as 2500 J/kg in spots. Kinematically speaking, veering low-level flow, overspread by strong northwesterlies will yield curved and elongated hodographs with 40-50 kts of effective bulk shear. The stronger storms are expected to become supercells, accompanied by severe wind and hail. There are some indications that a couple of stronger, sustained supercells may develop across eastern KS during the late afternoon to early evening hours. Given both the vertical shear profiles and colder temperatures aloft, a couple instances of 2+ inch hail and perhaps a tornado are possible. ..Squitieri.. 09/02/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1242 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Thunderstorms with potential for isolated severe wind gusts and hail will be possible today across parts of the northern Plains and upper Mississippi Valley. ...Northern Plains/Upper Mississippi Valley... North-northwesterly mid-level flow will continue across the Great Plains today, as a shortwave trough moves into the upper Mississippi Valley. At the surface, a cold front will advance southeastward across the northern Plains and upper Mississippi Valley. Ahead of the front, surface dewpoints in the lower to mid 60s F will contribute to the development of moderate instability by afternoon. As surface temperatures warm and low-level convergence becomes maximized along and ahead of the front, scattered convective initiation will be likely during the mid to late afternoon. Thunderstorms are expected to form and move southeastward across eastern South Dakota and central to southern Minnesota. Most late afternoon forecast soundings across that area by late afternoon have 0-6 km shear around 25 knots, with steep lapse rates between the surface and 850 mb. This should be sufficient for a marginal severe threat. The stronger multicells could be associated with isolated severe wind gusts and hail. ..Broyles/Thornton.. 09/02/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1242 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Thunderstorms with potential for isolated severe wind gusts and hail will be possible today across parts of the northern Plains and upper Mississippi Valley. ...Northern Plains/Upper Mississippi Valley... North-northwesterly mid-level flow will continue across the Great Plains today, as a shortwave trough moves into the upper Mississippi Valley. At the surface, a cold front will advance southeastward across the northern Plains and upper Mississippi Valley. Ahead of the front, surface dewpoints in the lower to mid 60s F will contribute to the development of moderate instability by afternoon. As surface temperatures warm and low-level convergence becomes maximized along and ahead of the front, scattered convective initiation will be likely during the mid to late afternoon. Thunderstorms are expected to form and move southeastward across eastern South Dakota and central to southern Minnesota. Most late afternoon forecast soundings across that area by late afternoon have 0-6 km shear around 25 knots, with steep lapse rates between the surface and 850 mb. This should be sufficient for a marginal severe threat. The stronger multicells could be associated with isolated severe wind gusts and hail. ..Broyles/Thornton.. 09/02/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1242 AM CDT Tue Sep 02 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Thunderstorms with potential for isolated severe wind gusts and hail will be possible today across parts of the northern Plains and upper Mississippi Valley. ...Northern Plains/Upper Mississippi Valley... North-northwesterly mid-level flow will continue across the Great Plains today, as a shortwave trough moves into the upper Mississippi Valley. At the surface, a cold front will advance southeastward across the northern Plains and upper Mississippi Valley. Ahead of the front, surface dewpoints in the lower to mid 60s F will contribute to the development of moderate instability by afternoon. As surface temperatures warm and low-level convergence becomes maximized along and ahead of the front, scattered convective initiation will be likely during the mid to late afternoon. Thunderstorms are expected to form and move southeastward across eastern South Dakota and central to southern Minnesota. Most late afternoon forecast soundings across that area by late afternoon have 0-6 km shear around 25 knots, with steep lapse rates between the surface and 850 mb. This should be sufficient for a marginal severe threat. The stronger multicells could be associated with isolated severe wind gusts and hail. ..Broyles/Thornton.. 09/02/2025 Read more