Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sun Sep 01 2024 Valid 011300Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN APPALACHIANS INTO THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND... ...SUMMARY... Strong thunderstorms capable of producing isolated damaging winds may occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a weak front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Morning visible satellite imagery shows plentiful cloud cover near this boundary, and downstream across parts of NC and the Mid-Atlantic into southern New England. Still, filtered daytime heating of a moist low-level airmass should allow at least weak instability to develop by early to mid afternoon along and south/east of the front, even though mid-level lapse rates will remain poor. The glancing influence/ascent of an upper trough over eastern Canada, along with weak orographic lift, will likely encourage convection development through the afternoon and early evening. Mid-level flow and related deep-layer shear are forecast to remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Still, enough flow and related shear may be present to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, while posing some threat for isolated strong to damaging winds as they move generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability is forecast this afternoon. But, confidence in a more organized wind threat remains too low to include greater severe wind probabilities. ...Western/Northern New York into Northern New England... As the primary upper trough and related surface cold front continue eastward across Ontario/Quebec today, daytime heating of a modestly moist low-level airmass will occur over parts of western/northern NY. Although poor mid-level lapse rates will likely hinder the development of any more than weak instability across this area (MLCAPE generally 500 J/kg of less), low/mid-level winds and related shear in the cloud-bearing layer is expected to strengthen through this afternoon with the approach of the upper trough. Some high-resolution/convection-allowing model guidance shows a low-topped line of thunderstorms developing this afternoon along or just ahead of the cold front. As low-level lapse rates steepen with daytime heating, some of this convection could produce isolated strong to severe wind gusts given the strengthening low/mid-level flow expected. The area impacted should remain fairly small across western/northern NY (generally downstream of Lake Ontario) due to more even more limited instability farther east across central NY into northern New England. ..Gleason/Leitman.. 09/01/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sun Sep 01 2024 Valid 011300Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN APPALACHIANS INTO THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND... ...SUMMARY... Strong thunderstorms capable of producing isolated damaging winds may occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a weak front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Morning visible satellite imagery shows plentiful cloud cover near this boundary, and downstream across parts of NC and the Mid-Atlantic into southern New England. Still, filtered daytime heating of a moist low-level airmass should allow at least weak instability to develop by early to mid afternoon along and south/east of the front, even though mid-level lapse rates will remain poor. The glancing influence/ascent of an upper trough over eastern Canada, along with weak orographic lift, will likely encourage convection development through the afternoon and early evening. Mid-level flow and related deep-layer shear are forecast to remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Still, enough flow and related shear may be present to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, while posing some threat for isolated strong to damaging winds as they move generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability is forecast this afternoon. But, confidence in a more organized wind threat remains too low to include greater severe wind probabilities. ...Western/Northern New York into Northern New England... As the primary upper trough and related surface cold front continue eastward across Ontario/Quebec today, daytime heating of a modestly moist low-level airmass will occur over parts of western/northern NY. Although poor mid-level lapse rates will likely hinder the development of any more than weak instability across this area (MLCAPE generally 500 J/kg of less), low/mid-level winds and related shear in the cloud-bearing layer is expected to strengthen through this afternoon with the approach of the upper trough. Some high-resolution/convection-allowing model guidance shows a low-topped line of thunderstorms developing this afternoon along or just ahead of the cold front. As low-level lapse rates steepen with daytime heating, some of this convection could produce isolated strong to severe wind gusts given the strengthening low/mid-level flow expected. The area impacted should remain fairly small across western/northern NY (generally downstream of Lake Ontario) due to more even more limited instability farther east across central NY into northern New England. ..Gleason/Leitman.. 09/01/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sun Sep 01 2024 Valid 011300Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE SOUTHERN APPALACHIANS INTO THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND... ...SUMMARY... Strong thunderstorms capable of producing isolated damaging winds may occur this afternoon across parts of the southern Appalachians into the Mid-Atlantic and southern New England. ...Southern Appalachians into the Mid-Atlantic and Southern New England... Thunderstorms should gradually increase in coverage this afternoon along/south of a weak front that extends from the Mid-South/lower OH Valley into the Mid-Atlantic. Morning visible satellite imagery shows plentiful cloud cover near this boundary, and downstream across parts of NC and the Mid-Atlantic into southern New England. Still, filtered daytime heating of a moist low-level airmass should allow at least weak instability to develop by early to mid afternoon along and south/east of the front, even though mid-level lapse rates will remain poor. The glancing influence/ascent of an upper trough over eastern Canada, along with weak orographic lift, will likely encourage convection development through the afternoon and early evening. Mid-level flow and related deep-layer shear are forecast to remain fairly modest, especially with southward extent across the Mid-Atlantic into the Carolinas and southern Appalachians. Still, enough flow and related shear may be present to support modest thunderstorm organization. Multiple loosely organized multicell clusters may eventually develop and consolidate by late afternoon and early evening, while posing some threat for isolated strong to damaging winds as they move generally eastward. The greatest concentration of thunderstorms should exist across parts of southern VA into NC and upstate SC where greater instability is forecast this afternoon. But, confidence in a more organized wind threat remains too low to include greater severe wind probabilities. ...Western/Northern New York into Northern New England... As the primary upper trough and related surface cold front continue eastward across Ontario/Quebec today, daytime heating of a modestly moist low-level airmass will occur over parts of western/northern NY. Although poor mid-level lapse rates will likely hinder the development of any more than weak instability across this area (MLCAPE generally 500 J/kg of less), low/mid-level winds and related shear in the cloud-bearing layer is expected to strengthen through this afternoon with the approach of the upper trough. Some high-resolution/convection-allowing model guidance shows a low-topped line of thunderstorms developing this afternoon along or just ahead of the cold front. As low-level lapse rates steepen with daytime heating, some of this convection could produce isolated strong to severe wind gusts given the strengthening low/mid-level flow expected. The area impacted should remain fairly small across western/northern NY (generally downstream of Lake Ontario) due to more even more limited instability farther east across central NY into northern New England. ..Gleason/Leitman.. 09/01/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun Sep 01 2024 Valid 041200Z - 091200Z ...DISCUSSION... Similar to 24 hours prior, global model solutions with respect to the large-scale pattern evolution over the U.S. begin substantial divergence relatively early in the medium-range period. This deviation in solutions becomes readily apparent by Friday (Day 6), and the differences preclude any meaningful assessment of severe risk beyond Thursday (Day 5). Through Day 5, severe-weather risk appears likely to remain minimal. Though a cold front is forecast to cross the northern Plains Wednesday (Day 4) and the Upper Mississippi Valley/Upper Great Lakes region Thursday (Day 5), low-level moisture -- and thus potential for destabilization -- is forecast to remain limited ahead of the front. As such, appreciable severe risk appears unlikely at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun Sep 01 2024 Valid 041200Z - 091200Z ...DISCUSSION... Similar to 24 hours prior, global model solutions with respect to the large-scale pattern evolution over the U.S. begin substantial divergence relatively early in the medium-range period. This deviation in solutions becomes readily apparent by Friday (Day 6), and the differences preclude any meaningful assessment of severe risk beyond Thursday (Day 5). Through Day 5, severe-weather risk appears likely to remain minimal. Though a cold front is forecast to cross the northern Plains Wednesday (Day 4) and the Upper Mississippi Valley/Upper Great Lakes region Thursday (Day 5), low-level moisture -- and thus potential for destabilization -- is forecast to remain limited ahead of the front. As such, appreciable severe risk appears unlikely at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun Sep 01 2024 Valid 041200Z - 091200Z ...DISCUSSION... Similar to 24 hours prior, global model solutions with respect to the large-scale pattern evolution over the U.S. begin substantial divergence relatively early in the medium-range period. This deviation in solutions becomes readily apparent by Friday (Day 6), and the differences preclude any meaningful assessment of severe risk beyond Thursday (Day 5). Through Day 5, severe-weather risk appears likely to remain minimal. Though a cold front is forecast to cross the northern Plains Wednesday (Day 4) and the Upper Mississippi Valley/Upper Great Lakes region Thursday (Day 5), low-level moisture -- and thus potential for destabilization -- is forecast to remain limited ahead of the front. As such, appreciable severe risk appears unlikely at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun Sep 01 2024 Valid 041200Z - 091200Z ...DISCUSSION... Similar to 24 hours prior, global model solutions with respect to the large-scale pattern evolution over the U.S. begin substantial divergence relatively early in the medium-range period. This deviation in solutions becomes readily apparent by Friday (Day 6), and the differences preclude any meaningful assessment of severe risk beyond Thursday (Day 5). Through Day 5, severe-weather risk appears likely to remain minimal. Though a cold front is forecast to cross the northern Plains Wednesday (Day 4) and the Upper Mississippi Valley/Upper Great Lakes region Thursday (Day 5), low-level moisture -- and thus potential for destabilization -- is forecast to remain limited ahead of the front. As such, appreciable severe risk appears unlikely at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun Sep 01 2024 Valid 041200Z - 091200Z ...DISCUSSION... Similar to 24 hours prior, global model solutions with respect to the large-scale pattern evolution over the U.S. begin substantial divergence relatively early in the medium-range period. This deviation in solutions becomes readily apparent by Friday (Day 6), and the differences preclude any meaningful assessment of severe risk beyond Thursday (Day 5). Through Day 5, severe-weather risk appears likely to remain minimal. Though a cold front is forecast to cross the northern Plains Wednesday (Day 4) and the Upper Mississippi Valley/Upper Great Lakes region Thursday (Day 5), low-level moisture -- and thus potential for destabilization -- is forecast to remain limited ahead of the front. As such, appreciable severe risk appears unlikely at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun Sep 01 2024 Valid 041200Z - 091200Z ...DISCUSSION... Similar to 24 hours prior, global model solutions with respect to the large-scale pattern evolution over the U.S. begin substantial divergence relatively early in the medium-range period. This deviation in solutions becomes readily apparent by Friday (Day 6), and the differences preclude any meaningful assessment of severe risk beyond Thursday (Day 5). Through Day 5, severe-weather risk appears likely to remain minimal. Though a cold front is forecast to cross the northern Plains Wednesday (Day 4) and the Upper Mississippi Valley/Upper Great Lakes region Thursday (Day 5), low-level moisture -- and thus potential for destabilization -- is forecast to remain limited ahead of the front. As such, appreciable severe risk appears unlikely at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0349 AM CDT Sun Sep 01 2024 Valid 041200Z - 091200Z ...DISCUSSION... Similar to 24 hours prior, global model solutions with respect to the large-scale pattern evolution over the U.S. begin substantial divergence relatively early in the medium-range period. This deviation in solutions becomes readily apparent by Friday (Day 6), and the differences preclude any meaningful assessment of severe risk beyond Thursday (Day 5). Through Day 5, severe-weather risk appears likely to remain minimal. Though a cold front is forecast to cross the northern Plains Wednesday (Day 4) and the Upper Mississippi Valley/Upper Great Lakes region Thursday (Day 5), low-level moisture -- and thus potential for destabilization -- is forecast to remain limited ahead of the front. As such, appreciable severe risk appears unlikely at this time. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 AM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather risk should remain local/limited at best on Tuesday. ...Discussion... As a long-wave upper trough gradually vacates the northeastern U.S. Tuesday, an upstream short-wave trough is forecast to move slowly eastward across the northern Intermountain region. At the surface, a baroclinic zone should linger in the vicinity of the Gulf Coast through the period, while farther north, a cold front is forecast to emerge into the north-central states through the second half of the period, in tandem with the advance of the western U.S. upper system. As this upper system and associated front cross the northern Intermountain region Tuesday, weak destabilization is expected to support showers and isolated thunderstorms. Though CAPE will remain quite limited, a dry/mixed boundary layer may support locally strong wind gusts with a couple of the stronger storms. At this time however, risk appears too isolated to warrant MRGL risk inclusion. Elsewhere, showers and scattered thunderstorms are expected across portions of the south-central and southeastern states, near the remnant front. However, weak shear suggests storms will remain disorganized and generally sub-severe through the period. ..Goss.. 09/01/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 AM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather risk should remain local/limited at best on Tuesday. ...Discussion... As a long-wave upper trough gradually vacates the northeastern U.S. Tuesday, an upstream short-wave trough is forecast to move slowly eastward across the northern Intermountain region. At the surface, a baroclinic zone should linger in the vicinity of the Gulf Coast through the period, while farther north, a cold front is forecast to emerge into the north-central states through the second half of the period, in tandem with the advance of the western U.S. upper system. As this upper system and associated front cross the northern Intermountain region Tuesday, weak destabilization is expected to support showers and isolated thunderstorms. Though CAPE will remain quite limited, a dry/mixed boundary layer may support locally strong wind gusts with a couple of the stronger storms. At this time however, risk appears too isolated to warrant MRGL risk inclusion. Elsewhere, showers and scattered thunderstorms are expected across portions of the south-central and southeastern states, near the remnant front. However, weak shear suggests storms will remain disorganized and generally sub-severe through the period. ..Goss.. 09/01/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 AM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather risk should remain local/limited at best on Tuesday. ...Discussion... As a long-wave upper trough gradually vacates the northeastern U.S. Tuesday, an upstream short-wave trough is forecast to move slowly eastward across the northern Intermountain region. At the surface, a baroclinic zone should linger in the vicinity of the Gulf Coast through the period, while farther north, a cold front is forecast to emerge into the north-central states through the second half of the period, in tandem with the advance of the western U.S. upper system. As this upper system and associated front cross the northern Intermountain region Tuesday, weak destabilization is expected to support showers and isolated thunderstorms. Though CAPE will remain quite limited, a dry/mixed boundary layer may support locally strong wind gusts with a couple of the stronger storms. At this time however, risk appears too isolated to warrant MRGL risk inclusion. Elsewhere, showers and scattered thunderstorms are expected across portions of the south-central and southeastern states, near the remnant front. However, weak shear suggests storms will remain disorganized and generally sub-severe through the period. ..Goss.. 09/01/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 AM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather risk should remain local/limited at best on Tuesday. ...Discussion... As a long-wave upper trough gradually vacates the northeastern U.S. Tuesday, an upstream short-wave trough is forecast to move slowly eastward across the northern Intermountain region. At the surface, a baroclinic zone should linger in the vicinity of the Gulf Coast through the period, while farther north, a cold front is forecast to emerge into the north-central states through the second half of the period, in tandem with the advance of the western U.S. upper system. As this upper system and associated front cross the northern Intermountain region Tuesday, weak destabilization is expected to support showers and isolated thunderstorms. Though CAPE will remain quite limited, a dry/mixed boundary layer may support locally strong wind gusts with a couple of the stronger storms. At this time however, risk appears too isolated to warrant MRGL risk inclusion. Elsewhere, showers and scattered thunderstorms are expected across portions of the south-central and southeastern states, near the remnant front. However, weak shear suggests storms will remain disorganized and generally sub-severe through the period. ..Goss.. 09/01/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 AM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather risk should remain local/limited at best on Tuesday. ...Discussion... As a long-wave upper trough gradually vacates the northeastern U.S. Tuesday, an upstream short-wave trough is forecast to move slowly eastward across the northern Intermountain region. At the surface, a baroclinic zone should linger in the vicinity of the Gulf Coast through the period, while farther north, a cold front is forecast to emerge into the north-central states through the second half of the period, in tandem with the advance of the western U.S. upper system. As this upper system and associated front cross the northern Intermountain region Tuesday, weak destabilization is expected to support showers and isolated thunderstorms. Though CAPE will remain quite limited, a dry/mixed boundary layer may support locally strong wind gusts with a couple of the stronger storms. At this time however, risk appears too isolated to warrant MRGL risk inclusion. Elsewhere, showers and scattered thunderstorms are expected across portions of the south-central and southeastern states, near the remnant front. However, weak shear suggests storms will remain disorganized and generally sub-severe through the period. ..Goss.. 09/01/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0219 AM CDT Sun Sep 01 2024 Valid 031200Z - 041200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe weather risk should remain local/limited at best on Tuesday. ...Discussion... As a long-wave upper trough gradually vacates the northeastern U.S. Tuesday, an upstream short-wave trough is forecast to move slowly eastward across the northern Intermountain region. At the surface, a baroclinic zone should linger in the vicinity of the Gulf Coast through the period, while farther north, a cold front is forecast to emerge into the north-central states through the second half of the period, in tandem with the advance of the western U.S. upper system. As this upper system and associated front cross the northern Intermountain region Tuesday, weak destabilization is expected to support showers and isolated thunderstorms. Though CAPE will remain quite limited, a dry/mixed boundary layer may support locally strong wind gusts with a couple of the stronger storms. At this time however, risk appears too isolated to warrant MRGL risk inclusion. Elsewhere, showers and scattered thunderstorms are expected across portions of the south-central and southeastern states, near the remnant front. However, weak shear suggests storms will remain disorganized and generally sub-severe through the period. ..Goss.. 09/01/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0210 AM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... ...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. ..Moore.. 09/01/2024 ...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 0210 AM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... ...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. ..Moore.. 09/01/2024 ...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 0210 AM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... ...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. ..Moore.. 09/01/2024 ...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 0210 AM CDT Sun Sep 01 2024 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHEAST CALIFORNIA INTO SOUTHERN OREGON AND NORTHWEST NEVADA... ...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. ..Moore.. 09/01/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more