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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sun Sep 01 2024 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF UPSTATE NEW YORK AND SOUTHERN NEW ENGLAND INTO THE CAROLINAS AND SOUTHERN APPALACHIANS... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated damaging winds may still occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...20Z Update... The previous forecast remains on track, with only slight changes made to the thunder line to reflect the latest guidance consensus and observations. ..Squitieri.. 09/01/2024 .PREV DISCUSSION... /ISSUED 1125 AM CDT Sun Sep 01 2024/ ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a diffuse front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Late morning visible satellite imagery shows substantial cloud cover in the vicinity of the boundary. Nevertheless, daytime heating of a moist low-level air mass should allow at least weak/pockets of moderate instability to develop by early to mid afternoon along and south/east of the front. Modest ascent with an upper trough over eastern Canada and adjacent Great Lakes/Northeast U.S., in combination with orographic ascent, will likely contribute to thunderstorm development through the afternoon and early evening. Mid-level flow and related deep-layer shear will remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Mid-level flow should still prove sufficient to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, posing some threat for isolated strong to damaging winds while moving generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability (MLCAPE on the order of 2000-2500 J/kg) is forecast this afternoon. ...Western/Northern New York into Northern New England... The upper-level trough and associated surface cold front will move east today across Ontario/Quebec provinces and Northeast U.S., with weak surface-based instability possibly developing in advance of the front. This may result in a narrow, low-topped line of convection (possibly with little lightning) moving east and accompanied by some risk for strong/locally damaging gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sun Sep 01 2024 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF UPSTATE NEW YORK AND SOUTHERN NEW ENGLAND INTO THE CAROLINAS AND SOUTHERN APPALACHIANS... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated damaging winds may still occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...20Z Update... The previous forecast remains on track, with only slight changes made to the thunder line to reflect the latest guidance consensus and observations. ..Squitieri.. 09/01/2024 .PREV DISCUSSION... /ISSUED 1125 AM CDT Sun Sep 01 2024/ ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a diffuse front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Late morning visible satellite imagery shows substantial cloud cover in the vicinity of the boundary. Nevertheless, daytime heating of a moist low-level air mass should allow at least weak/pockets of moderate instability to develop by early to mid afternoon along and south/east of the front. Modest ascent with an upper trough over eastern Canada and adjacent Great Lakes/Northeast U.S., in combination with orographic ascent, will likely contribute to thunderstorm development through the afternoon and early evening. Mid-level flow and related deep-layer shear will remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Mid-level flow should still prove sufficient to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, posing some threat for isolated strong to damaging winds while moving generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability (MLCAPE on the order of 2000-2500 J/kg) is forecast this afternoon. ...Western/Northern New York into Northern New England... The upper-level trough and associated surface cold front will move east today across Ontario/Quebec provinces and Northeast U.S., with weak surface-based instability possibly developing in advance of the front. This may result in a narrow, low-topped line of convection (possibly with little lightning) moving east and accompanied by some risk for strong/locally damaging gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sun Sep 01 2024 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF UPSTATE NEW YORK AND SOUTHERN NEW ENGLAND INTO THE CAROLINAS AND SOUTHERN APPALACHIANS... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated damaging winds may still occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...20Z Update... The previous forecast remains on track, with only slight changes made to the thunder line to reflect the latest guidance consensus and observations. ..Squitieri.. 09/01/2024 .PREV DISCUSSION... /ISSUED 1125 AM CDT Sun Sep 01 2024/ ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a diffuse front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Late morning visible satellite imagery shows substantial cloud cover in the vicinity of the boundary. Nevertheless, daytime heating of a moist low-level air mass should allow at least weak/pockets of moderate instability to develop by early to mid afternoon along and south/east of the front. Modest ascent with an upper trough over eastern Canada and adjacent Great Lakes/Northeast U.S., in combination with orographic ascent, will likely contribute to thunderstorm development through the afternoon and early evening. Mid-level flow and related deep-layer shear will remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Mid-level flow should still prove sufficient to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, posing some threat for isolated strong to damaging winds while moving generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability (MLCAPE on the order of 2000-2500 J/kg) is forecast this afternoon. ...Western/Northern New York into Northern New England... The upper-level trough and associated surface cold front will move east today across Ontario/Quebec provinces and Northeast U.S., with weak surface-based instability possibly developing in advance of the front. This may result in a narrow, low-topped line of convection (possibly with little lightning) moving east and accompanied by some risk for strong/locally damaging gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sun Sep 01 2024 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF UPSTATE NEW YORK AND SOUTHERN NEW ENGLAND INTO THE CAROLINAS AND SOUTHERN APPALACHIANS... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated damaging winds may still occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...20Z Update... The previous forecast remains on track, with only slight changes made to the thunder line to reflect the latest guidance consensus and observations. ..Squitieri.. 09/01/2024 .PREV DISCUSSION... /ISSUED 1125 AM CDT Sun Sep 01 2024/ ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a diffuse front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Late morning visible satellite imagery shows substantial cloud cover in the vicinity of the boundary. Nevertheless, daytime heating of a moist low-level air mass should allow at least weak/pockets of moderate instability to develop by early to mid afternoon along and south/east of the front. Modest ascent with an upper trough over eastern Canada and adjacent Great Lakes/Northeast U.S., in combination with orographic ascent, will likely contribute to thunderstorm development through the afternoon and early evening. Mid-level flow and related deep-layer shear will remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Mid-level flow should still prove sufficient to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, posing some threat for isolated strong to damaging winds while moving generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability (MLCAPE on the order of 2000-2500 J/kg) is forecast this afternoon. ...Western/Northern New York into Northern New England... The upper-level trough and associated surface cold front will move east today across Ontario/Quebec provinces and Northeast U.S., with weak surface-based instability possibly developing in advance of the front. This may result in a narrow, low-topped line of convection (possibly with little lightning) moving east and accompanied by some risk for strong/locally damaging gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sun Sep 01 2024 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF UPSTATE NEW YORK AND SOUTHERN NEW ENGLAND INTO THE CAROLINAS AND SOUTHERN APPALACHIANS... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated damaging winds may still occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...20Z Update... The previous forecast remains on track, with only slight changes made to the thunder line to reflect the latest guidance consensus and observations. ..Squitieri.. 09/01/2024 .PREV DISCUSSION... /ISSUED 1125 AM CDT Sun Sep 01 2024/ ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a diffuse front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Late morning visible satellite imagery shows substantial cloud cover in the vicinity of the boundary. Nevertheless, daytime heating of a moist low-level air mass should allow at least weak/pockets of moderate instability to develop by early to mid afternoon along and south/east of the front. Modest ascent with an upper trough over eastern Canada and adjacent Great Lakes/Northeast U.S., in combination with orographic ascent, will likely contribute to thunderstorm development through the afternoon and early evening. Mid-level flow and related deep-layer shear will remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Mid-level flow should still prove sufficient to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, posing some threat for isolated strong to damaging winds while moving generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability (MLCAPE on the order of 2000-2500 J/kg) is forecast this afternoon. ...Western/Northern New York into Northern New England... The upper-level trough and associated surface cold front will move east today across Ontario/Quebec provinces and Northeast U.S., with weak surface-based instability possibly developing in advance of the front. This may result in a narrow, low-topped line of convection (possibly with little lightning) moving east and accompanied by some risk for strong/locally damaging gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sun Sep 01 2024 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF UPSTATE NEW YORK AND SOUTHERN NEW ENGLAND INTO THE CAROLINAS AND SOUTHERN APPALACHIANS... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated damaging winds may still occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...20Z Update... The previous forecast remains on track, with only slight changes made to the thunder line to reflect the latest guidance consensus and observations. ..Squitieri.. 09/01/2024 .PREV DISCUSSION... /ISSUED 1125 AM CDT Sun Sep 01 2024/ ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a diffuse front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Late morning visible satellite imagery shows substantial cloud cover in the vicinity of the boundary. Nevertheless, daytime heating of a moist low-level air mass should allow at least weak/pockets of moderate instability to develop by early to mid afternoon along and south/east of the front. Modest ascent with an upper trough over eastern Canada and adjacent Great Lakes/Northeast U.S., in combination with orographic ascent, will likely contribute to thunderstorm development through the afternoon and early evening. Mid-level flow and related deep-layer shear will remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Mid-level flow should still prove sufficient to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, posing some threat for isolated strong to damaging winds while moving generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability (MLCAPE on the order of 2000-2500 J/kg) is forecast this afternoon. ...Western/Northern New York into Northern New England... The upper-level trough and associated surface cold front will move east today across Ontario/Quebec provinces and Northeast U.S., with weak surface-based instability possibly developing in advance of the front. This may result in a narrow, low-topped line of convection (possibly with little lightning) moving east and accompanied by some risk for strong/locally damaging gusts. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Sun Sep 01 2024 Valid 012000Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF UPSTATE NEW YORK AND SOUTHERN NEW ENGLAND INTO THE CAROLINAS AND SOUTHERN APPALACHIANS... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated damaging winds may still occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...20Z Update... The previous forecast remains on track, with only slight changes made to the thunder line to reflect the latest guidance consensus and observations. ..Squitieri.. 09/01/2024 .PREV DISCUSSION... /ISSUED 1125 AM CDT Sun Sep 01 2024/ ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a diffuse front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Late morning visible satellite imagery shows substantial cloud cover in the vicinity of the boundary. Nevertheless, daytime heating of a moist low-level air mass should allow at least weak/pockets of moderate instability to develop by early to mid afternoon along and south/east of the front. Modest ascent with an upper trough over eastern Canada and adjacent Great Lakes/Northeast U.S., in combination with orographic ascent, will likely contribute to thunderstorm development through the afternoon and early evening. Mid-level flow and related deep-layer shear will remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Mid-level flow should still prove sufficient to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, posing some threat for isolated strong to damaging winds while moving generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability (MLCAPE on the order of 2000-2500 J/kg) is forecast this afternoon. ...Western/Northern New York into Northern New England... The upper-level trough and associated surface cold front will move east today across Ontario/Quebec provinces and Northeast U.S., with weak surface-based instability possibly developing in advance of the front. This may result in a narrow, low-topped line of convection (possibly with little lightning) moving east and accompanied by some risk for strong/locally damaging gusts. Read more

MD 2042 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHEASTERN NORTH CAROLINA INTO SOUTHEAST VIRGINIA
Mesoscale Discussion 2042 NWS Storm Prediction Center Norman OK 0153 PM CDT Sun Sep 01 2024 Areas affected...Portions of northeastern North Carolina into southeast Virginia Concerning...Severe potential...Watch unlikely Valid 011853Z - 012100Z Probability of Watch Issuance...5 percent SUMMARY...A small cluster of storms may produce strong to locally damaging winds through the remainder of the afternoon. A watch is not currently anticipated. DISCUSSION...Amid a weak mid-level lapse rate environment, storms that had initially formed on differential heating boundaries have now begun to cluster and show some modest signs of deepening. With cloud cover having mostly dissipated, temperatures have risen into the upper 80s/low 90s F in northeast North Carolina into southeastern Virginia. Steep low-level lapse rates could promote strong/damaging outflow gusts as convection propagates east-northeast. Weak deep-layer shear and lapse rates aloft will limit overall storm intensity/organization. ..Wendt/Bunting.. 09/01/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...MHX...RAH...RNK... LAT...LON 36927813 36917757 37047694 36997647 36897625 36527617 35847648 35637782 35807878 36057917 36437926 36767891 36927813 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... Minor adjustments were made to extend isolated dry thunderstorm chances further north into Washington/Idaho and to bring the Critical fire weather area further north into Oregon. This is in agreement with latest conditional probabilities from the HREF for sustained Critical wind/RH as well as conditional probability of thunder. See previous discussion for more information. ..Thornton.. 09/01/2024 .PREV DISCUSSION... /ISSUED 0210 AM CDT Sun Sep 01 2024/ ...Synopsis... Fire weather concerns are expected across parts of the Pacific Northwest/Great Basin as well as central to northern High Plains on Monday afternoon. ...Pacific Northwest/Great Basin... South/southwest mid-level flow along the West Coast will gradually increase over the next 24-48 hours with the approach of an upper wave currently off the northern CA coast. This will act to strengthen downslope flow off the northern Sierra Nevada with most deterministic and ensemble solutions indicating that winds between 15-25 mph will be common by peak heating Monday afternoon when RH values will fall into the teens. Elevated to critical fire weather conditions appear likely - especially across the CA/NV/OR tri-state region where the strongest winds are expected under the mid-level jet max. A warming trend over the past week (featuring multiple days of sub-20% RH minimums) has maintained ERC values well within the 80-90th percentiles across much of the Pacific Northwest and Great Basin. While thunderstorms are anticipated across parts of the region today (Sunday), little rain accumulation is expected, and holdover fires from dry-lightning starts may become more active Monday as winds increase. Dry thunderstorms will also be a concern across much of NV, central to eastern OR, and western ID. A plume of mid-level moisture (noted in 00z soundings and water-vapor imagery across NV into southern OR) is expected to continue spreading north through Monday afternoon. Lift associated with the wave should support another day of isolated thunderstorms. Dry boundary-layer conditions will promote limited rainfall and an attendant threat of dry lightning. While thunderstorms are possible across a broader swath of the region, the dry-lightning risk area was confined to areas with receptive fuels and low probability for wetting rainfall per ensemble guidance. ...High Plains... A surface high currently building across the northern Plains in the wake of a cold front is forecast to shift east towards the Midwest by Monday afternoon. Modest lee troughing juxtaposed with the nearby surface high will bolster southerly pressure gradient winds across northeast CO and western NE/SD. The displacement of richer low-level moisture to the south across the southern Plains will promote a dry return flow regime with afternoon RH values falling to near 20%. When combined with 15-20 mph winds and very dry fuels (ERCs are currently estimated to be above the 90th percentile), elevated to locally critical fire weather conditions appear probable. ...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 0252 PM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... Minor adjustments were made to extend isolated dry thunderstorm chances further north into Washington/Idaho and to bring the Critical fire weather area further north into Oregon. This is in agreement with latest conditional probabilities from the HREF for sustained Critical wind/RH as well as conditional probability of thunder. See previous discussion for more information. ..Thornton.. 09/01/2024 .PREV DISCUSSION... /ISSUED 0210 AM CDT Sun Sep 01 2024/ ...Synopsis... Fire weather concerns are expected across parts of the Pacific Northwest/Great Basin as well as central to northern High Plains on Monday afternoon. ...Pacific Northwest/Great Basin... South/southwest mid-level flow along the West Coast will gradually increase over the next 24-48 hours with the approach of an upper wave currently off the northern CA coast. This will act to strengthen downslope flow off the northern Sierra Nevada with most deterministic and ensemble solutions indicating that winds between 15-25 mph will be common by peak heating Monday afternoon when RH values will fall into the teens. Elevated to critical fire weather conditions appear likely - especially across the CA/NV/OR tri-state region where the strongest winds are expected under the mid-level jet max. A warming trend over the past week (featuring multiple days of sub-20% RH minimums) has maintained ERC values well within the 80-90th percentiles across much of the Pacific Northwest and Great Basin. While thunderstorms are anticipated across parts of the region today (Sunday), little rain accumulation is expected, and holdover fires from dry-lightning starts may become more active Monday as winds increase. Dry thunderstorms will also be a concern across much of NV, central to eastern OR, and western ID. A plume of mid-level moisture (noted in 00z soundings and water-vapor imagery across NV into southern OR) is expected to continue spreading north through Monday afternoon. Lift associated with the wave should support another day of isolated thunderstorms. Dry boundary-layer conditions will promote limited rainfall and an attendant threat of dry lightning. While thunderstorms are possible across a broader swath of the region, the dry-lightning risk area was confined to areas with receptive fuels and low probability for wetting rainfall per ensemble guidance. ...High Plains... A surface high currently building across the northern Plains in the wake of a cold front is forecast to shift east towards the Midwest by Monday afternoon. Modest lee troughing juxtaposed with the nearby surface high will bolster southerly pressure gradient winds across northeast CO and western NE/SD. The displacement of richer low-level moisture to the south across the southern Plains will promote a dry return flow regime with afternoon RH values falling to near 20%. When combined with 15-20 mph winds and very dry fuels (ERCs are currently estimated to be above the 90th percentile), elevated to locally critical fire weather conditions appear probable. ...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 0252 PM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... Minor adjustments were made to extend isolated dry thunderstorm chances further north into Washington/Idaho and to bring the Critical fire weather area further north into Oregon. This is in agreement with latest conditional probabilities from the HREF for sustained Critical wind/RH as well as conditional probability of thunder. See previous discussion for more information. ..Thornton.. 09/01/2024 .PREV DISCUSSION... /ISSUED 0210 AM CDT Sun Sep 01 2024/ ...Synopsis... Fire weather concerns are expected across parts of the Pacific Northwest/Great Basin as well as central to northern High Plains on Monday afternoon. ...Pacific Northwest/Great Basin... South/southwest mid-level flow along the West Coast will gradually increase over the next 24-48 hours with the approach of an upper wave currently off the northern CA coast. This will act to strengthen downslope flow off the northern Sierra Nevada with most deterministic and ensemble solutions indicating that winds between 15-25 mph will be common by peak heating Monday afternoon when RH values will fall into the teens. Elevated to critical fire weather conditions appear likely - especially across the CA/NV/OR tri-state region where the strongest winds are expected under the mid-level jet max. A warming trend over the past week (featuring multiple days of sub-20% RH minimums) has maintained ERC values well within the 80-90th percentiles across much of the Pacific Northwest and Great Basin. While thunderstorms are anticipated across parts of the region today (Sunday), little rain accumulation is expected, and holdover fires from dry-lightning starts may become more active Monday as winds increase. Dry thunderstorms will also be a concern across much of NV, central to eastern OR, and western ID. A plume of mid-level moisture (noted in 00z soundings and water-vapor imagery across NV into southern OR) is expected to continue spreading north through Monday afternoon. Lift associated with the wave should support another day of isolated thunderstorms. Dry boundary-layer conditions will promote limited rainfall and an attendant threat of dry lightning. While thunderstorms are possible across a broader swath of the region, the dry-lightning risk area was confined to areas with receptive fuels and low probability for wetting rainfall per ensemble guidance. ...High Plains... A surface high currently building across the northern Plains in the wake of a cold front is forecast to shift east towards the Midwest by Monday afternoon. Modest lee troughing juxtaposed with the nearby surface high will bolster southerly pressure gradient winds across northeast CO and western NE/SD. The displacement of richer low-level moisture to the south across the southern Plains will promote a dry return flow regime with afternoon RH values falling to near 20%. When combined with 15-20 mph winds and very dry fuels (ERCs are currently estimated to be above the 90th percentile), elevated to locally critical fire weather conditions appear probable. ...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 0252 PM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... Minor adjustments were made to extend isolated dry thunderstorm chances further north into Washington/Idaho and to bring the Critical fire weather area further north into Oregon. This is in agreement with latest conditional probabilities from the HREF for sustained Critical wind/RH as well as conditional probability of thunder. See previous discussion for more information. ..Thornton.. 09/01/2024 .PREV DISCUSSION... /ISSUED 0210 AM CDT Sun Sep 01 2024/ ...Synopsis... Fire weather concerns are expected across parts of the Pacific Northwest/Great Basin as well as central to northern High Plains on Monday afternoon. ...Pacific Northwest/Great Basin... South/southwest mid-level flow along the West Coast will gradually increase over the next 24-48 hours with the approach of an upper wave currently off the northern CA coast. This will act to strengthen downslope flow off the northern Sierra Nevada with most deterministic and ensemble solutions indicating that winds between 15-25 mph will be common by peak heating Monday afternoon when RH values will fall into the teens. Elevated to critical fire weather conditions appear likely - especially across the CA/NV/OR tri-state region where the strongest winds are expected under the mid-level jet max. A warming trend over the past week (featuring multiple days of sub-20% RH minimums) has maintained ERC values well within the 80-90th percentiles across much of the Pacific Northwest and Great Basin. While thunderstorms are anticipated across parts of the region today (Sunday), little rain accumulation is expected, and holdover fires from dry-lightning starts may become more active Monday as winds increase. Dry thunderstorms will also be a concern across much of NV, central to eastern OR, and western ID. A plume of mid-level moisture (noted in 00z soundings and water-vapor imagery across NV into southern OR) is expected to continue spreading north through Monday afternoon. Lift associated with the wave should support another day of isolated thunderstorms. Dry boundary-layer conditions will promote limited rainfall and an attendant threat of dry lightning. While thunderstorms are possible across a broader swath of the region, the dry-lightning risk area was confined to areas with receptive fuels and low probability for wetting rainfall per ensemble guidance. ...High Plains... A surface high currently building across the northern Plains in the wake of a cold front is forecast to shift east towards the Midwest by Monday afternoon. Modest lee troughing juxtaposed with the nearby surface high will bolster southerly pressure gradient winds across northeast CO and western NE/SD. The displacement of richer low-level moisture to the south across the southern Plains will promote a dry return flow regime with afternoon RH values falling to near 20%. When combined with 15-20 mph winds and very dry fuels (ERCs are currently estimated to be above the 90th percentile), elevated to locally critical fire weather conditions appear probable. ...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 0252 PM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... Minor adjustments were made to extend isolated dry thunderstorm chances further north into Washington/Idaho and to bring the Critical fire weather area further north into Oregon. This is in agreement with latest conditional probabilities from the HREF for sustained Critical wind/RH as well as conditional probability of thunder. See previous discussion for more information. ..Thornton.. 09/01/2024 .PREV DISCUSSION... /ISSUED 0210 AM CDT Sun Sep 01 2024/ ...Synopsis... Fire weather concerns are expected across parts of the Pacific Northwest/Great Basin as well as central to northern High Plains on Monday afternoon. ...Pacific Northwest/Great Basin... South/southwest mid-level flow along the West Coast will gradually increase over the next 24-48 hours with the approach of an upper wave currently off the northern CA coast. This will act to strengthen downslope flow off the northern Sierra Nevada with most deterministic and ensemble solutions indicating that winds between 15-25 mph will be common by peak heating Monday afternoon when RH values will fall into the teens. Elevated to critical fire weather conditions appear likely - especially across the CA/NV/OR tri-state region where the strongest winds are expected under the mid-level jet max. A warming trend over the past week (featuring multiple days of sub-20% RH minimums) has maintained ERC values well within the 80-90th percentiles across much of the Pacific Northwest and Great Basin. While thunderstorms are anticipated across parts of the region today (Sunday), little rain accumulation is expected, and holdover fires from dry-lightning starts may become more active Monday as winds increase. Dry thunderstorms will also be a concern across much of NV, central to eastern OR, and western ID. A plume of mid-level moisture (noted in 00z soundings and water-vapor imagery across NV into southern OR) is expected to continue spreading north through Monday afternoon. Lift associated with the wave should support another day of isolated thunderstorms. Dry boundary-layer conditions will promote limited rainfall and an attendant threat of dry lightning. While thunderstorms are possible across a broader swath of the region, the dry-lightning risk area was confined to areas with receptive fuels and low probability for wetting rainfall per ensemble guidance. ...High Plains... A surface high currently building across the northern Plains in the wake of a cold front is forecast to shift east towards the Midwest by Monday afternoon. Modest lee troughing juxtaposed with the nearby surface high will bolster southerly pressure gradient winds across northeast CO and western NE/SD. The displacement of richer low-level moisture to the south across the southern Plains will promote a dry return flow regime with afternoon RH values falling to near 20%. When combined with 15-20 mph winds and very dry fuels (ERCs are currently estimated to be above the 90th percentile), elevated to locally critical fire weather conditions appear probable. ...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 0252 PM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... Minor adjustments were made to extend isolated dry thunderstorm chances further north into Washington/Idaho and to bring the Critical fire weather area further north into Oregon. This is in agreement with latest conditional probabilities from the HREF for sustained Critical wind/RH as well as conditional probability of thunder. See previous discussion for more information. ..Thornton.. 09/01/2024 .PREV DISCUSSION... /ISSUED 0210 AM CDT Sun Sep 01 2024/ ...Synopsis... Fire weather concerns are expected across parts of the Pacific Northwest/Great Basin as well as central to northern High Plains on Monday afternoon. ...Pacific Northwest/Great Basin... South/southwest mid-level flow along the West Coast will gradually increase over the next 24-48 hours with the approach of an upper wave currently off the northern CA coast. This will act to strengthen downslope flow off the northern Sierra Nevada with most deterministic and ensemble solutions indicating that winds between 15-25 mph will be common by peak heating Monday afternoon when RH values will fall into the teens. Elevated to critical fire weather conditions appear likely - especially across the CA/NV/OR tri-state region where the strongest winds are expected under the mid-level jet max. A warming trend over the past week (featuring multiple days of sub-20% RH minimums) has maintained ERC values well within the 80-90th percentiles across much of the Pacific Northwest and Great Basin. While thunderstorms are anticipated across parts of the region today (Sunday), little rain accumulation is expected, and holdover fires from dry-lightning starts may become more active Monday as winds increase. Dry thunderstorms will also be a concern across much of NV, central to eastern OR, and western ID. A plume of mid-level moisture (noted in 00z soundings and water-vapor imagery across NV into southern OR) is expected to continue spreading north through Monday afternoon. Lift associated with the wave should support another day of isolated thunderstorms. Dry boundary-layer conditions will promote limited rainfall and an attendant threat of dry lightning. While thunderstorms are possible across a broader swath of the region, the dry-lightning risk area was confined to areas with receptive fuels and low probability for wetting rainfall per ensemble guidance. ...High Plains... A surface high currently building across the northern Plains in the wake of a cold front is forecast to shift east towards the Midwest by Monday afternoon. Modest lee troughing juxtaposed with the nearby surface high will bolster southerly pressure gradient winds across northeast CO and western NE/SD. The displacement of richer low-level moisture to the south across the southern Plains will promote a dry return flow regime with afternoon RH values falling to near 20%. When combined with 15-20 mph winds and very dry fuels (ERCs are currently estimated to be above the 90th percentile), elevated to locally critical fire weather conditions appear probable. ...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 0252 PM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... Minor adjustments were made to extend isolated dry thunderstorm chances further north into Washington/Idaho and to bring the Critical fire weather area further north into Oregon. This is in agreement with latest conditional probabilities from the HREF for sustained Critical wind/RH as well as conditional probability of thunder. See previous discussion for more information. ..Thornton.. 09/01/2024 .PREV DISCUSSION... /ISSUED 0210 AM CDT Sun Sep 01 2024/ ...Synopsis... Fire weather concerns are expected across parts of the Pacific Northwest/Great Basin as well as central to northern High Plains on Monday afternoon. ...Pacific Northwest/Great Basin... South/southwest mid-level flow along the West Coast will gradually increase over the next 24-48 hours with the approach of an upper wave currently off the northern CA coast. This will act to strengthen downslope flow off the northern Sierra Nevada with most deterministic and ensemble solutions indicating that winds between 15-25 mph will be common by peak heating Monday afternoon when RH values will fall into the teens. Elevated to critical fire weather conditions appear likely - especially across the CA/NV/OR tri-state region where the strongest winds are expected under the mid-level jet max. A warming trend over the past week (featuring multiple days of sub-20% RH minimums) has maintained ERC values well within the 80-90th percentiles across much of the Pacific Northwest and Great Basin. While thunderstorms are anticipated across parts of the region today (Sunday), little rain accumulation is expected, and holdover fires from dry-lightning starts may become more active Monday as winds increase. Dry thunderstorms will also be a concern across much of NV, central to eastern OR, and western ID. A plume of mid-level moisture (noted in 00z soundings and water-vapor imagery across NV into southern OR) is expected to continue spreading north through Monday afternoon. Lift associated with the wave should support another day of isolated thunderstorms. Dry boundary-layer conditions will promote limited rainfall and an attendant threat of dry lightning. While thunderstorms are possible across a broader swath of the region, the dry-lightning risk area was confined to areas with receptive fuels and low probability for wetting rainfall per ensemble guidance. ...High Plains... A surface high currently building across the northern Plains in the wake of a cold front is forecast to shift east towards the Midwest by Monday afternoon. Modest lee troughing juxtaposed with the nearby surface high will bolster southerly pressure gradient winds across northeast CO and western NE/SD. The displacement of richer low-level moisture to the south across the southern Plains will promote a dry return flow regime with afternoon RH values falling to near 20%. When combined with 15-20 mph winds and very dry fuels (ERCs are currently estimated to be above the 90th percentile), elevated to locally critical fire weather conditions appear probable. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 PM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EASTERN IDAHO INTO SOUTHWEST MONTANA AND WESTERN WYOMING... ...SUMMARY... A few strong storms may produce hail and gusty winds over parts of eastern Idaho, southwest Montana, and western Wyoming on Tuesday. ...Synopsis... On Tuesday, an upper trough will move east across ID into MT and WY, weakening during that time. Cooling aloft will still accompany this wave, with 500 mb wind speeds around 30-35 kt. Meanwhile, a larger upper trough will quickly exit the Northeast, with height rises over the Great Lakes and upper MS Valley. At the surface, a prominent high will affect much of the eastern CONUS, providing relatively stable conditions. A trough will develop during the afternoon over the northern High Plains, with the primary cold front affecting parts of the northern Rockies in association with the a shortwave trough moving across ID, MT, and WY. ...ID into MT and WY... Cool temperatures aloft will support early/ongoing showers and a few thunderstorms on Tuesday, with increasing coverage as heating occurs into parts of eastern ID, southwest MT and western WY. As the trough progresses east, scattered strong to marginally severe storms may develop as instability increases with heating. Steeper lapse rates aloft as well as elongated hodographs with effective deep-layer shear around 40 kt will favor cellular storm mode with hail, perhaps to severe levels. Veering winds with height and perhaps 100 m2/s2 SRH may support a supercell or two as well. ..Jewell.. 09/01/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 PM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EASTERN IDAHO INTO SOUTHWEST MONTANA AND WESTERN WYOMING... ...SUMMARY... A few strong storms may produce hail and gusty winds over parts of eastern Idaho, southwest Montana, and western Wyoming on Tuesday. ...Synopsis... On Tuesday, an upper trough will move east across ID into MT and WY, weakening during that time. Cooling aloft will still accompany this wave, with 500 mb wind speeds around 30-35 kt. Meanwhile, a larger upper trough will quickly exit the Northeast, with height rises over the Great Lakes and upper MS Valley. At the surface, a prominent high will affect much of the eastern CONUS, providing relatively stable conditions. A trough will develop during the afternoon over the northern High Plains, with the primary cold front affecting parts of the northern Rockies in association with the a shortwave trough moving across ID, MT, and WY. ...ID into MT and WY... Cool temperatures aloft will support early/ongoing showers and a few thunderstorms on Tuesday, with increasing coverage as heating occurs into parts of eastern ID, southwest MT and western WY. As the trough progresses east, scattered strong to marginally severe storms may develop as instability increases with heating. Steeper lapse rates aloft as well as elongated hodographs with effective deep-layer shear around 40 kt will favor cellular storm mode with hail, perhaps to severe levels. Veering winds with height and perhaps 100 m2/s2 SRH may support a supercell or two as well. ..Jewell.. 09/01/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 PM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EASTERN IDAHO INTO SOUTHWEST MONTANA AND WESTERN WYOMING... ...SUMMARY... A few strong storms may produce hail and gusty winds over parts of eastern Idaho, southwest Montana, and western Wyoming on Tuesday. ...Synopsis... On Tuesday, an upper trough will move east across ID into MT and WY, weakening during that time. Cooling aloft will still accompany this wave, with 500 mb wind speeds around 30-35 kt. Meanwhile, a larger upper trough will quickly exit the Northeast, with height rises over the Great Lakes and upper MS Valley. At the surface, a prominent high will affect much of the eastern CONUS, providing relatively stable conditions. A trough will develop during the afternoon over the northern High Plains, with the primary cold front affecting parts of the northern Rockies in association with the a shortwave trough moving across ID, MT, and WY. ...ID into MT and WY... Cool temperatures aloft will support early/ongoing showers and a few thunderstorms on Tuesday, with increasing coverage as heating occurs into parts of eastern ID, southwest MT and western WY. As the trough progresses east, scattered strong to marginally severe storms may develop as instability increases with heating. Steeper lapse rates aloft as well as elongated hodographs with effective deep-layer shear around 40 kt will favor cellular storm mode with hail, perhaps to severe levels. Veering winds with height and perhaps 100 m2/s2 SRH may support a supercell or two as well. ..Jewell.. 09/01/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 PM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EASTERN IDAHO INTO SOUTHWEST MONTANA AND WESTERN WYOMING... ...SUMMARY... A few strong storms may produce hail and gusty winds over parts of eastern Idaho, southwest Montana, and western Wyoming on Tuesday. ...Synopsis... On Tuesday, an upper trough will move east across ID into MT and WY, weakening during that time. Cooling aloft will still accompany this wave, with 500 mb wind speeds around 30-35 kt. Meanwhile, a larger upper trough will quickly exit the Northeast, with height rises over the Great Lakes and upper MS Valley. At the surface, a prominent high will affect much of the eastern CONUS, providing relatively stable conditions. A trough will develop during the afternoon over the northern High Plains, with the primary cold front affecting parts of the northern Rockies in association with the a shortwave trough moving across ID, MT, and WY. ...ID into MT and WY... Cool temperatures aloft will support early/ongoing showers and a few thunderstorms on Tuesday, with increasing coverage as heating occurs into parts of eastern ID, southwest MT and western WY. As the trough progresses east, scattered strong to marginally severe storms may develop as instability increases with heating. Steeper lapse rates aloft as well as elongated hodographs with effective deep-layer shear around 40 kt will favor cellular storm mode with hail, perhaps to severe levels. Veering winds with height and perhaps 100 m2/s2 SRH may support a supercell or two as well. ..Jewell.. 09/01/2024 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 PM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF EASTERN IDAHO INTO SOUTHWEST MONTANA AND WESTERN WYOMING... ...SUMMARY... A few strong storms may produce hail and gusty winds over parts of eastern Idaho, southwest Montana, and western Wyoming on Tuesday. ...Synopsis... On Tuesday, an upper trough will move east across ID into MT and WY, weakening during that time. Cooling aloft will still accompany this wave, with 500 mb wind speeds around 30-35 kt. Meanwhile, a larger upper trough will quickly exit the Northeast, with height rises over the Great Lakes and upper MS Valley. At the surface, a prominent high will affect much of the eastern CONUS, providing relatively stable conditions. A trough will develop during the afternoon over the northern High Plains, with the primary cold front affecting parts of the northern Rockies in association with the a shortwave trough moving across ID, MT, and WY. ...ID into MT and WY... Cool temperatures aloft will support early/ongoing showers and a few thunderstorms on Tuesday, with increasing coverage as heating occurs into parts of eastern ID, southwest MT and western WY. As the trough progresses east, scattered strong to marginally severe storms may develop as instability increases with heating. Steeper lapse rates aloft as well as elongated hodographs with effective deep-layer shear around 40 kt will favor cellular storm mode with hail, perhaps to severe levels. Veering winds with height and perhaps 100 m2/s2 SRH may support a supercell or two as well. ..Jewell.. 09/01/2024 Read more