Aggregator

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 0215 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...Update... Some minor changes were made to the Isolated Dry Thunderstorm area for Saturday. The latest model trends regarding the track and ascent associated with the initial mid-level shortwave trough moving onshore suggest additional lightning strikes may occur further west over the Cascades of WA. Farther south, into portions of the northern Great Basin and far southeastern OR, fuels appear far less receptive. Therefore, some of this region was trimmed out of the isolated area. Please see the previous discussion below for additional details. ..Barnes.. 09/05/2025 .PREV DISCUSSION... /ISSUED 0152 AM CDT Fri Sep 05 2025/ ...Synopsis... A mid-level trough will continue to approach the East Coast as upper ridging builds over the Rockies and a mid-level trough remains in place along the Pacific Northwest coast tomorrow (Saturday). A mid-level impulse will pivot around the northwestern trough, providing locally stronger upper support for dry and breezy conditions across northern California into southern Oregon. At the moment, the overlap of 15+ mph sustained southwesterly surface winds amid 15-20 percent RH seem to be too localized to warrant Elevated highlights at this time. Of greater concern is the development of scattered thunderstorms ahead of the mid-level trough over parts of the Pacific Northwest into the northern Rockies. Here, a mix of wet and dry storm modes will overspread a dry boundary layer, as well as dry fuel beds. Storm motions will be relatively slow. However, the high receptiveness of the fuels may compensate for possible wet, slow moving storms to support lightning-induced ignitions, warranting the introduction of isolated dry thunderstorm highlights. ...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 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Fri Sep 05 2025 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN PENNSYLVANIA AND NEW JERSEY NORTHEASTWARD INTO FAR SOUTHERN MAINE... ...SUMMARY... Scattered strong to severe thunderstorms are most likely Saturday from eastern Pennsylvania and New Jersey into parts of southern New England. Isolated strong gusts are possible extending southward across the Piedmont. ...Synopsis... A leading mid/upper level speed max will pivot northeastward across Quebec on Saturday, with the right-entrance region sweeping across much of the northeastern states. Given the trajectory, only subtle height falls will occur over the region, but midlevel southwest winds will increase to around 60 kt, enhancing deep-layer shear. This cyclonic pattern aloft will extend well south across the Appalachians, where winds will be much weaker. However, relatively cool midlevel temperatures will aid destabilization in these areas. At the surface, a cold front will push east from ME into northern VA, with a moist air mass ahead of it. Winds at 850 mb will increase to 30-40 kt across the Northeast, which will aid the northward transport of moisture and destabilization. ...Northeast... A wave of low pressure is forecast to develop over eastern PA early in the day, translating northeastward along the front and into ME by late afternoon. Stronger heating and steep low-level lapse rates should develop from VA into eastern PA/NJ and into interior southern New England, with MLCAPE around 1500 J/kg as an areal average. As the warm air mass develops and accelerates north ahead of the cold front, both instability and shear parameter space will become favorable for severe storms, including supercell potential. A line of storms is expected by 17 to 18Z, from eastern PA toward the Hudson Valley, expanding N/S and pushing east through the afternoon. Given 40-50 kt effective deep-layer shear and enhanced low-level shear with the midday surface theta-e surge, the initial storm mode may be cellular along the boundary, with a brief tornado or two possible along with some hail. Damaging winds are then most likely as outflows merge, and spread east across the remainder of the region through late afternoon. ...Piedmont... Strong heating will occur across most of the area, with areas of high-level clouds expected across the Appalachians. The moist/uncapped air mass and weak surface trough should yield scattered afternoon storms. Despite weak shear, favorable timing with peak heating/steep boundary layer lapse rates as well as up to 2000 J/kg MUCAPE may yield locally strong to damaging downbursts. A few storms could produce marginal hail given sufficient longevity. ..Jewell.. 09/05/2025 Read more

000
ABPZ20 KNHC 051710
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
Issued by the NWS Weather Prediction Center College Park MD
1100 AM PDT Fri Sep 5 2025

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

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Kiko, located in the East Pacific basin well east-southeast of the
Hawaiian Islands. Kiko is expected to cross into the central
Pacific basin tonight or early Saturday morning.


Central East Pacific:
An area of low pressure could develop in the central
portion of the eastern Pacific well to the south of the Baja
California Peninsula during the early portion of next week. Some
slow development of this system is possible thereafter as it moves
generally westward over the open waters of the East Pacific.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

$$
Forecaster Roth/Papin

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Sep 05 2025 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY AND UPPER OHIO VALLEY... ...SUMMARY... Scattered damaging winds, isolated severe hail, and a brief tornado or two are possible from the Upper Ohio to Tennessee Valleys, mainly late this afternoon and evening. ...Ohio Valley/Central Appalachians to the Tennessee Valley... A large-scale upper trough/low will remain centered over Ontario today, with mid/upper-level troughing extending southward across much of the Great Lakes/Midwest into the OH Valley. A cold front will continue to advance slowly southeastward across portions of the Mid-South and OH Valley through this evening. Daytime heating of a seasonably moist low-level airmass ahead of this front over the TN Valley will likely yield upwards of 1500-2500 J/kg MLCAPE by late afternoon, mainly in KY/TN. Weaker instability is forecast with northward extent into the upper OH Valley and central Appalachians. Forcing for ascent aloft will remain nebulous for much of the day, with generally neutral mid-level heights and stronger flow remaining confined to the north of the surface cold front. Still, a subtle mid-level perturbation over eastern KS and the Ozarks late this morning should continue eastward towards the Mid-South and lower OH Valley by late afternoon/early evening. This feature, along with modest low-level convergence along the front, may be sufficient to encourage initial convective development by 21-23Z across parts of KY/TN. Even with stronger flow aloft remaining displaced to the north of the surface warm sector, some veering and gradual strengthening with height through mid/upper levels should support sufficient deep-layer shear for updraft organization. Current expectations are for multiple clusters to develop and pose a risk for mainly severe/damaging winds as they spread eastward across the TN and upper OH Valleys through the late afternoon and evening. With cool temperatures aloft and marginal deep-layer shear to support supercells, some of this activity could also pose a threat for isolated hail, especially any cells that can remain at least semi-discrete. A brief tornado or two also appears possible, although low-level shear should remain fairly limited given veered/west-southwesterly low-level flow. With a relatively narrow warm sector expected, convection should generally weaken this evening as it moves into the higher terrain of the central Appalachians and encounters a less unstable airmass. ...Mid-South to North Texas... An elongated mid-level thermal trough, characterized by 500 mb temperatures around -8 to -12 C per RAP analysis and 12Z OUN/FWD observed soundings, extends into much of OK and north TX, well to the south of the vertically stacked cyclone over Ontario. Low to mid-level flow should remain modest across this region, with some signal from various NAM/RAP forecast soundings of a veer-back-veer signature. Strong speed shear should remain confined above 500 mb, coincident with poor upper-level lapse rates atop steeper mid-level lapse rates. This suggests a messy convective mode should be common as convection increases in the late afternoon and evening, along the more west/east-oriented portion of the surface cold front. Have maintained the Marginal Risk for an isolated severe hail/wind threat with a small westward expansion with this update. ...Oregon... Isolated to scattered thunderstorms should develop today across parts of OR as a weak mid-level trough moves northward across the Pacific Northwest Coast. While low/mid-level flow is expected to remain rather modest, steepened low-level lapse rates could support isolated strong/gusty winds with any high-based convection that develops this afternoon/evening. ..Gleason/Weinman.. 09/05/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Sep 05 2025 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY AND UPPER OHIO VALLEY... ...SUMMARY... Scattered damaging winds, isolated severe hail, and a brief tornado or two are possible from the Upper Ohio to Tennessee Valleys, mainly late this afternoon and evening. ...Ohio Valley/Central Appalachians to the Tennessee Valley... A large-scale upper trough/low will remain centered over Ontario today, with mid/upper-level troughing extending southward across much of the Great Lakes/Midwest into the OH Valley. A cold front will continue to advance slowly southeastward across portions of the Mid-South and OH Valley through this evening. Daytime heating of a seasonably moist low-level airmass ahead of this front over the TN Valley will likely yield upwards of 1500-2500 J/kg MLCAPE by late afternoon, mainly in KY/TN. Weaker instability is forecast with northward extent into the upper OH Valley and central Appalachians. Forcing for ascent aloft will remain nebulous for much of the day, with generally neutral mid-level heights and stronger flow remaining confined to the north of the surface cold front. Still, a subtle mid-level perturbation over eastern KS and the Ozarks late this morning should continue eastward towards the Mid-South and lower OH Valley by late afternoon/early evening. This feature, along with modest low-level convergence along the front, may be sufficient to encourage initial convective development by 21-23Z across parts of KY/TN. Even with stronger flow aloft remaining displaced to the north of the surface warm sector, some veering and gradual strengthening with height through mid/upper levels should support sufficient deep-layer shear for updraft organization. Current expectations are for multiple clusters to develop and pose a risk for mainly severe/damaging winds as they spread eastward across the TN and upper OH Valleys through the late afternoon and evening. With cool temperatures aloft and marginal deep-layer shear to support supercells, some of this activity could also pose a threat for isolated hail, especially any cells that can remain at least semi-discrete. A brief tornado or two also appears possible, although low-level shear should remain fairly limited given veered/west-southwesterly low-level flow. With a relatively narrow warm sector expected, convection should generally weaken this evening as it moves into the higher terrain of the central Appalachians and encounters a less unstable airmass. ...Mid-South to North Texas... An elongated mid-level thermal trough, characterized by 500 mb temperatures around -8 to -12 C per RAP analysis and 12Z OUN/FWD observed soundings, extends into much of OK and north TX, well to the south of the vertically stacked cyclone over Ontario. Low to mid-level flow should remain modest across this region, with some signal from various NAM/RAP forecast soundings of a veer-back-veer signature. Strong speed shear should remain confined above 500 mb, coincident with poor upper-level lapse rates atop steeper mid-level lapse rates. This suggests a messy convective mode should be common as convection increases in the late afternoon and evening, along the more west/east-oriented portion of the surface cold front. Have maintained the Marginal Risk for an isolated severe hail/wind threat with a small westward expansion with this update. ...Oregon... Isolated to scattered thunderstorms should develop today across parts of OR as a weak mid-level trough moves northward across the Pacific Northwest Coast. While low/mid-level flow is expected to remain rather modest, steepened low-level lapse rates could support isolated strong/gusty winds with any high-based convection that develops this afternoon/evening. ..Gleason/Weinman.. 09/05/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Sep 05 2025 Valid 051630Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE TENNESSEE VALLEY AND UPPER OHIO VALLEY... ...SUMMARY... Scattered damaging winds, isolated severe hail, and a brief tornado or two are possible from the Upper Ohio to Tennessee Valleys, mainly late this afternoon and evening. ...Ohio Valley/Central Appalachians to the Tennessee Valley... A large-scale upper trough/low will remain centered over Ontario today, with mid/upper-level troughing extending southward across much of the Great Lakes/Midwest into the OH Valley. A cold front will continue to advance slowly southeastward across portions of the Mid-South and OH Valley through this evening. Daytime heating of a seasonably moist low-level airmass ahead of this front over the TN Valley will likely yield upwards of 1500-2500 J/kg MLCAPE by late afternoon, mainly in KY/TN. Weaker instability is forecast with northward extent into the upper OH Valley and central Appalachians. Forcing for ascent aloft will remain nebulous for much of the day, with generally neutral mid-level heights and stronger flow remaining confined to the north of the surface cold front. Still, a subtle mid-level perturbation over eastern KS and the Ozarks late this morning should continue eastward towards the Mid-South and lower OH Valley by late afternoon/early evening. This feature, along with modest low-level convergence along the front, may be sufficient to encourage initial convective development by 21-23Z across parts of KY/TN. Even with stronger flow aloft remaining displaced to the north of the surface warm sector, some veering and gradual strengthening with height through mid/upper levels should support sufficient deep-layer shear for updraft organization. Current expectations are for multiple clusters to develop and pose a risk for mainly severe/damaging winds as they spread eastward across the TN and upper OH Valleys through the late afternoon and evening. With cool temperatures aloft and marginal deep-layer shear to support supercells, some of this activity could also pose a threat for isolated hail, especially any cells that can remain at least semi-discrete. A brief tornado or two also appears possible, although low-level shear should remain fairly limited given veered/west-southwesterly low-level flow. With a relatively narrow warm sector expected, convection should generally weaken this evening as it moves into the higher terrain of the central Appalachians and encounters a less unstable airmass. ...Mid-South to North Texas... An elongated mid-level thermal trough, characterized by 500 mb temperatures around -8 to -12 C per RAP analysis and 12Z OUN/FWD observed soundings, extends into much of OK and north TX, well to the south of the vertically stacked cyclone over Ontario. Low to mid-level flow should remain modest across this region, with some signal from various NAM/RAP forecast soundings of a veer-back-veer signature. Strong speed shear should remain confined above 500 mb, coincident with poor upper-level lapse rates atop steeper mid-level lapse rates. This suggests a messy convective mode should be common as convection increases in the late afternoon and evening, along the more west/east-oriented portion of the surface cold front. Have maintained the Marginal Risk for an isolated severe hail/wind threat with a small westward expansion with this update. ...Oregon... Isolated to scattered thunderstorms should develop today across parts of OR as a weak mid-level trough moves northward across the Pacific Northwest Coast. While low/mid-level flow is expected to remain rather modest, steepened low-level lapse rates could support isolated strong/gusty winds with any high-based convection that develops this afternoon/evening. ..Gleason/Weinman.. 09/05/2025 Read more