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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Fri Sep 06 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible Saturday over parts of the Northeast and Mid Atlantic, the central Rockies/High Plains, Florida, and across parts of the Southwest. No severe weather is expected. ...Synopsis and Discussion... A deep upper low/trough will move eastward across the Great Lakes and toward the Northeast, becoming negatively tilted and resulting in substantial cooling aloft. At the surface, a cold front will extend south from a low over southern Quebec, roughly from the Hudson Valley into the Piedmont around 18Z. While dewpoints in the 60s F will exist ahead of the cold front, instability will be minimal and generally less than 500 J/kg due to a shallow/cool boundary layer. In addition, low-level shear will not be particularly strong, with modest warm advection around 850 mb. As such, severe weather is not anticipated with this system despite the strong upper trough. Elsewhere, northwest flow will exist across the central High Plains east of the upper ridge, with around 1000 J/kg MUCAPE developing. Dewpoints may struggle to reach 50 F, though isolated thunderstorms are expected with locally gusty winds or small hail over northeast CO into western NE during the late afternoon. ..Jewell.. 09/06/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Fri Sep 06 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible Saturday over parts of the Northeast and Mid Atlantic, the central Rockies/High Plains, Florida, and across parts of the Southwest. No severe weather is expected. ...Synopsis and Discussion... A deep upper low/trough will move eastward across the Great Lakes and toward the Northeast, becoming negatively tilted and resulting in substantial cooling aloft. At the surface, a cold front will extend south from a low over southern Quebec, roughly from the Hudson Valley into the Piedmont around 18Z. While dewpoints in the 60s F will exist ahead of the cold front, instability will be minimal and generally less than 500 J/kg due to a shallow/cool boundary layer. In addition, low-level shear will not be particularly strong, with modest warm advection around 850 mb. As such, severe weather is not anticipated with this system despite the strong upper trough. Elsewhere, northwest flow will exist across the central High Plains east of the upper ridge, with around 1000 J/kg MUCAPE developing. Dewpoints may struggle to reach 50 F, though isolated thunderstorms are expected with locally gusty winds or small hail over northeast CO into western NE during the late afternoon. ..Jewell.. 09/06/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Fri Sep 06 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible Saturday over parts of the Northeast and Mid Atlantic, the central Rockies/High Plains, Florida, and across parts of the Southwest. No severe weather is expected. ...Synopsis and Discussion... A deep upper low/trough will move eastward across the Great Lakes and toward the Northeast, becoming negatively tilted and resulting in substantial cooling aloft. At the surface, a cold front will extend south from a low over southern Quebec, roughly from the Hudson Valley into the Piedmont around 18Z. While dewpoints in the 60s F will exist ahead of the cold front, instability will be minimal and generally less than 500 J/kg due to a shallow/cool boundary layer. In addition, low-level shear will not be particularly strong, with modest warm advection around 850 mb. As such, severe weather is not anticipated with this system despite the strong upper trough. Elsewhere, northwest flow will exist across the central High Plains east of the upper ridge, with around 1000 J/kg MUCAPE developing. Dewpoints may struggle to reach 50 F, though isolated thunderstorms are expected with locally gusty winds or small hail over northeast CO into western NE during the late afternoon. ..Jewell.. 09/06/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Fri Sep 06 2024 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms will be possible Saturday over parts of the Northeast and Mid Atlantic, the central Rockies/High Plains, Florida, and across parts of the Southwest. No severe weather is expected. ...Synopsis and Discussion... A deep upper low/trough will move eastward across the Great Lakes and toward the Northeast, becoming negatively tilted and resulting in substantial cooling aloft. At the surface, a cold front will extend south from a low over southern Quebec, roughly from the Hudson Valley into the Piedmont around 18Z. While dewpoints in the 60s F will exist ahead of the cold front, instability will be minimal and generally less than 500 J/kg due to a shallow/cool boundary layer. In addition, low-level shear will not be particularly strong, with modest warm advection around 850 mb. As such, severe weather is not anticipated with this system despite the strong upper trough. Elsewhere, northwest flow will exist across the central High Plains east of the upper ridge, with around 1000 J/kg MUCAPE developing. Dewpoints may struggle to reach 50 F, though isolated thunderstorms are expected with locally gusty winds or small hail over northeast CO into western NE during the late afternoon. ..Jewell.. 09/06/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ...Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ...Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. ..Mosier/Dean.. 09/06/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ...Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ...Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. ..Mosier/Dean.. 09/06/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ...Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ...Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. ..Mosier/Dean.. 09/06/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ...Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ...Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. ..Mosier/Dean.. 09/06/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ...Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ...Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. ..Mosier/Dean.. 09/06/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ...Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ...Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. ..Mosier/Dean.. 09/06/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061630Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LAKE ERIE ACROSS MUCH OF OHIO AND INTO SOUTHEAST INDIANA AND NORTHERN KENTUCKY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio and into southeast Indiana and northern Kentucky. ...Lower Great Lakes into the OH Valley... Morning satellite imagery shows a well-defined shortwave trough moving through the Upper Midwest and into the Mid MS/Lower OH Valley. This shortwave trough is expected to continue eastward/southeastward through OH Valley during the day, progressing through the base of the parent upper trough over Ontario. Recent surface analysis places the low associated with this wave over southwestern Ontario. A cold front extends southwestward from this low across the middle/lower OH Valley and the Ozark Plateau before continuing through central and southwest OK. Low-level airmass ahead of this front across much of the OH Valley is characterized by mid 60s dewpoints. This low-level moisture is forecast to advect northeastward into the Upper OH Valley in a fairly narrow corridor ahead of the front throughout the day, although boundary-layer mixing could drop dewpoints into the upper 50s by the afternoon. This low-level moisture will help support modest buoyancy as the airmass diurnally warms, although the overall buoyancy will be limited by both the boundary-layer mixing and persistence of warm mid-level temperatures. There should still be enough buoyancy to support thunderstorm development along the front during the afternoon. The stronger mid-level flow, and resultant stronger vertical shear, will lag behind the front, while also having a more front-parallel structure. This orientation, coupled with the modest buoyancy and weak pre-frontal convergence, could result in quick undercutting of any updrafts, leading to a more anafrontal character to the storms. Even so, isolated thunderstorms may remain in the warm sector long enough to produce a few damaging gusts. Isolated hail is possible as well, even as storms become displaced behind the front. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ...Elsewhere... Isolated to widely scattered thunderstorms are possible along the front from Mid-South vicinity across AR into northwest TX. Weak buoyancy and shear should mitigate storm intensity, keeping the severe potential low. Numerous thunderstorms are anticipated from the Gulf Coast into FL, amid the tropical airmass in place. A few water-loaded downbursts capable of damaging gusts are possible, particularly across the FL Peninsula. ..Mosier/Dean.. 09/06/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Fri Sep 06 2024 Valid 061700Z - 071200Z The dry thunderstorm area from the northern Sierra into the Northwest was adjusted to account for the most recent guidance. Thunderstorms also appear likely in parts of the southern Sierra, but diminishing mid/upper-level winds should keep storm motions slow and potential for greater wetting rainfall higher. ..Wendt.. 09/06/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Fri Sep 06 2024/ ...Synopsis... Mid-level ridging centered over the Great Basin is forecast to slowly decay today as a weak upper trough approaches the Pacific Coast. Ahead of the weak trough, a modest influx of mid-level moisture and ascent will overspread the northern Sierra and southern Cascades. Adequate buoyancy will develop with daytime heating supporting isolated thunderstorms through the evening hours. Beneath the advancing mid-level moisture, dry boundary-layer profiles and storm motions of 20-25 kt will favor low to very low rainfall efficiency with these storms. With thunderstorms expected atop areas of receptive fuels, dry lightning appears probable. Additionally, strengthening southwesterly mid-level flow should enhance downslope winds and low relative humidity across northern CA into northwest NV. Areas of brief elevated fire weather conditions are possible, though the duration and coverage should remain limited. ...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 1127 AM CDT Fri Sep 06 2024 Valid 061700Z - 071200Z The dry thunderstorm area from the northern Sierra into the Northwest was adjusted to account for the most recent guidance. Thunderstorms also appear likely in parts of the southern Sierra, but diminishing mid/upper-level winds should keep storm motions slow and potential for greater wetting rainfall higher. ..Wendt.. 09/06/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Fri Sep 06 2024/ ...Synopsis... Mid-level ridging centered over the Great Basin is forecast to slowly decay today as a weak upper trough approaches the Pacific Coast. Ahead of the weak trough, a modest influx of mid-level moisture and ascent will overspread the northern Sierra and southern Cascades. Adequate buoyancy will develop with daytime heating supporting isolated thunderstorms through the evening hours. Beneath the advancing mid-level moisture, dry boundary-layer profiles and storm motions of 20-25 kt will favor low to very low rainfall efficiency with these storms. With thunderstorms expected atop areas of receptive fuels, dry lightning appears probable. Additionally, strengthening southwesterly mid-level flow should enhance downslope winds and low relative humidity across northern CA into northwest NV. Areas of brief elevated fire weather conditions are possible, though the duration and coverage should remain limited. ...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 1127 AM CDT Fri Sep 06 2024 Valid 061700Z - 071200Z The dry thunderstorm area from the northern Sierra into the Northwest was adjusted to account for the most recent guidance. Thunderstorms also appear likely in parts of the southern Sierra, but diminishing mid/upper-level winds should keep storm motions slow and potential for greater wetting rainfall higher. ..Wendt.. 09/06/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Fri Sep 06 2024/ ...Synopsis... Mid-level ridging centered over the Great Basin is forecast to slowly decay today as a weak upper trough approaches the Pacific Coast. Ahead of the weak trough, a modest influx of mid-level moisture and ascent will overspread the northern Sierra and southern Cascades. Adequate buoyancy will develop with daytime heating supporting isolated thunderstorms through the evening hours. Beneath the advancing mid-level moisture, dry boundary-layer profiles and storm motions of 20-25 kt will favor low to very low rainfall efficiency with these storms. With thunderstorms expected atop areas of receptive fuels, dry lightning appears probable. Additionally, strengthening southwesterly mid-level flow should enhance downslope winds and low relative humidity across northern CA into northwest NV. Areas of brief elevated fire weather conditions are possible, though the duration and coverage should remain limited. ...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 1127 AM CDT Fri Sep 06 2024 Valid 061700Z - 071200Z The dry thunderstorm area from the northern Sierra into the Northwest was adjusted to account for the most recent guidance. Thunderstorms also appear likely in parts of the southern Sierra, but diminishing mid/upper-level winds should keep storm motions slow and potential for greater wetting rainfall higher. ..Wendt.. 09/06/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Fri Sep 06 2024/ ...Synopsis... Mid-level ridging centered over the Great Basin is forecast to slowly decay today as a weak upper trough approaches the Pacific Coast. Ahead of the weak trough, a modest influx of mid-level moisture and ascent will overspread the northern Sierra and southern Cascades. Adequate buoyancy will develop with daytime heating supporting isolated thunderstorms through the evening hours. Beneath the advancing mid-level moisture, dry boundary-layer profiles and storm motions of 20-25 kt will favor low to very low rainfall efficiency with these storms. With thunderstorms expected atop areas of receptive fuels, dry lightning appears probable. Additionally, strengthening southwesterly mid-level flow should enhance downslope winds and low relative humidity across northern CA into northwest NV. Areas of brief elevated fire weather conditions are possible, though the duration and coverage should remain limited. ...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 1127 AM CDT Fri Sep 06 2024 Valid 061700Z - 071200Z The dry thunderstorm area from the northern Sierra into the Northwest was adjusted to account for the most recent guidance. Thunderstorms also appear likely in parts of the southern Sierra, but diminishing mid/upper-level winds should keep storm motions slow and potential for greater wetting rainfall higher. ..Wendt.. 09/06/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Fri Sep 06 2024/ ...Synopsis... Mid-level ridging centered over the Great Basin is forecast to slowly decay today as a weak upper trough approaches the Pacific Coast. Ahead of the weak trough, a modest influx of mid-level moisture and ascent will overspread the northern Sierra and southern Cascades. Adequate buoyancy will develop with daytime heating supporting isolated thunderstorms through the evening hours. Beneath the advancing mid-level moisture, dry boundary-layer profiles and storm motions of 20-25 kt will favor low to very low rainfall efficiency with these storms. With thunderstorms expected atop areas of receptive fuels, dry lightning appears probable. Additionally, strengthening southwesterly mid-level flow should enhance downslope winds and low relative humidity across northern CA into northwest NV. Areas of brief elevated fire weather conditions are possible, though the duration and coverage should remain limited. ...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 1127 AM CDT Fri Sep 06 2024 Valid 061700Z - 071200Z The dry thunderstorm area from the northern Sierra into the Northwest was adjusted to account for the most recent guidance. Thunderstorms also appear likely in parts of the southern Sierra, but diminishing mid/upper-level winds should keep storm motions slow and potential for greater wetting rainfall higher. ..Wendt.. 09/06/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Fri Sep 06 2024/ ...Synopsis... Mid-level ridging centered over the Great Basin is forecast to slowly decay today as a weak upper trough approaches the Pacific Coast. Ahead of the weak trough, a modest influx of mid-level moisture and ascent will overspread the northern Sierra and southern Cascades. Adequate buoyancy will develop with daytime heating supporting isolated thunderstorms through the evening hours. Beneath the advancing mid-level moisture, dry boundary-layer profiles and storm motions of 20-25 kt will favor low to very low rainfall efficiency with these storms. With thunderstorms expected atop areas of receptive fuels, dry lightning appears probable. Additionally, strengthening southwesterly mid-level flow should enhance downslope winds and low relative humidity across northern CA into northwest NV. Areas of brief elevated fire weather conditions are possible, though the duration and coverage should remain limited. ...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 1127 AM CDT Fri Sep 06 2024 Valid 061700Z - 071200Z The dry thunderstorm area from the northern Sierra into the Northwest was adjusted to account for the most recent guidance. Thunderstorms also appear likely in parts of the southern Sierra, but diminishing mid/upper-level winds should keep storm motions slow and potential for greater wetting rainfall higher. ..Wendt.. 09/06/2024 .PREV DISCUSSION... /ISSUED 0151 AM CDT Fri Sep 06 2024/ ...Synopsis... Mid-level ridging centered over the Great Basin is forecast to slowly decay today as a weak upper trough approaches the Pacific Coast. Ahead of the weak trough, a modest influx of mid-level moisture and ascent will overspread the northern Sierra and southern Cascades. Adequate buoyancy will develop with daytime heating supporting isolated thunderstorms through the evening hours. Beneath the advancing mid-level moisture, dry boundary-layer profiles and storm motions of 20-25 kt will favor low to very low rainfall efficiency with these storms. With thunderstorms expected atop areas of receptive fuels, dry lightning appears probable. Additionally, strengthening southwesterly mid-level flow should enhance downslope winds and low relative humidity across northern CA into northwest NV. Areas of brief elevated fire weather conditions are possible, though the duration and coverage should remain limited. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Fri Sep 06 2024 Valid 061300Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF OHIO TO THE OHIO VALLEY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio to the Ohio Valley. ...Synopsis... A highly amplified mid/upper-level pattern will persist across the CONUS, but with some weakening of the western mean ridge and intensification of troughing over the Great Lakes/Ohio Valley regions. The latter will occur in relation to a synoptic-scale trough with several accompanying vorticity maxima and broad cyclonic flow -- apparent in moisture-channel imagery over much of northern ON and the Lake Superior vicinity. Phasing of accompanying shortwaves/ vorticity lobes will contribute to both amplification and wavelength shortening through the period. A closed 500-mb low should develop around 00Z near the eastern end of Upper MI, with trough near an MKG-ORD-MVN line. By 12Z, a fully developed cyclone should cover much of ON from the southern end of James Bay to Lake Erie, with 500-mb trough extending southwestward near a CVG-BNA line. Associated cyclonic flow at that time will cover most of the CONUS over and east of the mid/upper Mississippi Valley. At the surface, a cold front related to the ON trough was drawn at 11Z near a DTW-FDY-IND-ICT line. This front should proceed eastward/southeastward across the Ohio Valley, Lower Great Lakes and into the central/northern Appalachians through the period, ahead of the mid/upper trough. By 00Z, the front should extend from Lake Ontario across western parts of NY/PA to southeastern OH, northern middle to western TN, and AR, becoming diffuse amidst northeast flow on both sides over OK. Northeasterlies over the southern Plains south of the cold front will be largely in isallobaric response to a deepening surface frontal-wave low over the northwestern Gulf, initially drawn about 100 nm south of GLS, and forecast to drift erratically eastward through tonight. Strong/organized convection related to the Gulf cyclone is expected to remain over water through the period. ...OH, Ohio Valley... Damaging to isolated, marginally severe gusts, as well as marginal hail, will be possible with thunderstorms moving eastward across the outlook area today. A broken line of convection -- including widely scattered non-severe thunderstorms -- is apparent this morning from northwestern OH to western MO approximately along the low-level cold front. This activity, or succeeding/newer development after a short time gap later this morning -- should become better organized between Lake Erie and the Ohio Valley around midday as the foregoing boundary layer (and prospective inflow) destabilizes. This will occur in response to a combination of warm advection and diurnal heating/ mixing, whose mixing-related moisture-reduction effects will be counterbalanced to some extent by moist advection. Activity should move into a narrow corridor of 50s to mid 60s F surface dewpoints, combining with diurnal heating to support patchy, highly variable MLCAPE in the 500-1500 J/kg range. Substantial westerly component to prefrontal near-surface flow will limit both convergence and vertical shear, though weak MLCINH will permit frontal development/maintenance of thunderstorms, regardless. Around 30-35 kt effective-shear magnitudes will support mainly multicells, though some intermittent/transient supercell character will be possible for longer-lived, discrete cells. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ..Edwards/Kerr.. 09/06/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Fri Sep 06 2024 Valid 061300Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF OHIO TO THE OHIO VALLEY... ...SUMMARY... Strong to locally severe storms are possible this afternoon from Lake Erie across much of Ohio to the Ohio Valley. ...Synopsis... A highly amplified mid/upper-level pattern will persist across the CONUS, but with some weakening of the western mean ridge and intensification of troughing over the Great Lakes/Ohio Valley regions. The latter will occur in relation to a synoptic-scale trough with several accompanying vorticity maxima and broad cyclonic flow -- apparent in moisture-channel imagery over much of northern ON and the Lake Superior vicinity. Phasing of accompanying shortwaves/ vorticity lobes will contribute to both amplification and wavelength shortening through the period. A closed 500-mb low should develop around 00Z near the eastern end of Upper MI, with trough near an MKG-ORD-MVN line. By 12Z, a fully developed cyclone should cover much of ON from the southern end of James Bay to Lake Erie, with 500-mb trough extending southwestward near a CVG-BNA line. Associated cyclonic flow at that time will cover most of the CONUS over and east of the mid/upper Mississippi Valley. At the surface, a cold front related to the ON trough was drawn at 11Z near a DTW-FDY-IND-ICT line. This front should proceed eastward/southeastward across the Ohio Valley, Lower Great Lakes and into the central/northern Appalachians through the period, ahead of the mid/upper trough. By 00Z, the front should extend from Lake Ontario across western parts of NY/PA to southeastern OH, northern middle to western TN, and AR, becoming diffuse amidst northeast flow on both sides over OK. Northeasterlies over the southern Plains south of the cold front will be largely in isallobaric response to a deepening surface frontal-wave low over the northwestern Gulf, initially drawn about 100 nm south of GLS, and forecast to drift erratically eastward through tonight. Strong/organized convection related to the Gulf cyclone is expected to remain over water through the period. ...OH, Ohio Valley... Damaging to isolated, marginally severe gusts, as well as marginal hail, will be possible with thunderstorms moving eastward across the outlook area today. A broken line of convection -- including widely scattered non-severe thunderstorms -- is apparent this morning from northwestern OH to western MO approximately along the low-level cold front. This activity, or succeeding/newer development after a short time gap later this morning -- should become better organized between Lake Erie and the Ohio Valley around midday as the foregoing boundary layer (and prospective inflow) destabilizes. This will occur in response to a combination of warm advection and diurnal heating/ mixing, whose mixing-related moisture-reduction effects will be counterbalanced to some extent by moist advection. Activity should move into a narrow corridor of 50s to mid 60s F surface dewpoints, combining with diurnal heating to support patchy, highly variable MLCAPE in the 500-1500 J/kg range. Substantial westerly component to prefrontal near-surface flow will limit both convergence and vertical shear, though weak MLCINH will permit frontal development/maintenance of thunderstorms, regardless. Around 30-35 kt effective-shear magnitudes will support mainly multicells, though some intermittent/transient supercell character will be possible for longer-lived, discrete cells. Activity should weaken this evening as it moves eastward out of the most favorable moisture, and into a nocturnally cooling/stabilizing boundary layer. ..Edwards/Kerr.. 09/06/2024 Read more