Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 10 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LA COAST... ...SUMMARY... Some tornado threat associated with Tropical Cyclone Francine may approach the Louisiana Coast by early Wednesday morning. ...Synopsis... A shortwave trough is expected to be off the Northeast Coast early Tuesday morning, with continued eastward progression into the northern Atlantic expected thereafter. A relatively zonal pattern is anticipated west of this shortwave trough across the majority of the CONUS throughout much of the period. A low-amplitude shortwave trough is forecast to move within this zonal flow across the northern Plains and the Upper Midwest, but with minimal pattern amplification. Some amplification is expected late Tuesday/early Wednesday across the Pacific Northwest, ahead of a strong shortwave trough approaching the coast. Surface pattern early Tuesday will feature high pressure centered over the central Appalachians and covering much of the OH Valley. This ridging is expected to gradually shift eastward/northeastward throughout the period. Surface troughing associated with the northern Plains shortwave trough will extend across the central Dakotas early Tuesday, before then shifting eastward throughout the day. Farther south across the northwest Gulf of Mexico, TC Francine is expected to reach hurricane strength while gradually progressing northeastward. ...TC Francine - LA Coast... Rainbands from Francine will likely spread across the northwest Gulf Coast throughout the day, but the stronger flow will remain displaced south throughout much of the period. Beginning around 06Z, the stronger flow may be far enough north to influence any deeper updrafts that develop along the LA Coast, with an attendant risk for brief tornadoes. ...Upper Midwest... Moderate low-level moisture, characterized by surface dewpoints in the upper 50s/low 60s, is expected across the region Tuesday afternoon ahead of the approaching shortwave trough and associated surface trough. Steep mid-level lapse rates will aid in the development of strong buoyancy across the region, supporting a conditional severe-thunderstorm risk. However, despite moderate low-level moisture and strong daytime heating, warm mid-level temperatures are forecast to keep capping in place, precluding afternoon thunderstorm development. ...Elsewhere... Afternoon thunderstorms are expected again across the eastern Great Basin and northern/central Rockies, where orographic effects and modest large-scale ascent will combine with modest moisture and buoyancy to support thunderstorm development. Increasing thunderstorm potential is anticipated late Tuesday into early Wednesday across the Pacific Northwest ahead of the approaching shortwave trough. ..Mosier/Lyons.. 09/10/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 10 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LA COAST... ...SUMMARY... Some tornado threat associated with Tropical Cyclone Francine may approach the Louisiana Coast by early Wednesday morning. ...Synopsis... A shortwave trough is expected to be off the Northeast Coast early Tuesday morning, with continued eastward progression into the northern Atlantic expected thereafter. A relatively zonal pattern is anticipated west of this shortwave trough across the majority of the CONUS throughout much of the period. A low-amplitude shortwave trough is forecast to move within this zonal flow across the northern Plains and the Upper Midwest, but with minimal pattern amplification. Some amplification is expected late Tuesday/early Wednesday across the Pacific Northwest, ahead of a strong shortwave trough approaching the coast. Surface pattern early Tuesday will feature high pressure centered over the central Appalachians and covering much of the OH Valley. This ridging is expected to gradually shift eastward/northeastward throughout the period. Surface troughing associated with the northern Plains shortwave trough will extend across the central Dakotas early Tuesday, before then shifting eastward throughout the day. Farther south across the northwest Gulf of Mexico, TC Francine is expected to reach hurricane strength while gradually progressing northeastward. ...TC Francine - LA Coast... Rainbands from Francine will likely spread across the northwest Gulf Coast throughout the day, but the stronger flow will remain displaced south throughout much of the period. Beginning around 06Z, the stronger flow may be far enough north to influence any deeper updrafts that develop along the LA Coast, with an attendant risk for brief tornadoes. ...Upper Midwest... Moderate low-level moisture, characterized by surface dewpoints in the upper 50s/low 60s, is expected across the region Tuesday afternoon ahead of the approaching shortwave trough and associated surface trough. Steep mid-level lapse rates will aid in the development of strong buoyancy across the region, supporting a conditional severe-thunderstorm risk. However, despite moderate low-level moisture and strong daytime heating, warm mid-level temperatures are forecast to keep capping in place, precluding afternoon thunderstorm development. ...Elsewhere... Afternoon thunderstorms are expected again across the eastern Great Basin and northern/central Rockies, where orographic effects and modest large-scale ascent will combine with modest moisture and buoyancy to support thunderstorm development. Increasing thunderstorm potential is anticipated late Tuesday into early Wednesday across the Pacific Northwest ahead of the approaching shortwave trough. ..Mosier/Lyons.. 09/10/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 10 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LA COAST... ...SUMMARY... Some tornado threat associated with Tropical Cyclone Francine may approach the Louisiana Coast by early Wednesday morning. ...Synopsis... A shortwave trough is expected to be off the Northeast Coast early Tuesday morning, with continued eastward progression into the northern Atlantic expected thereafter. A relatively zonal pattern is anticipated west of this shortwave trough across the majority of the CONUS throughout much of the period. A low-amplitude shortwave trough is forecast to move within this zonal flow across the northern Plains and the Upper Midwest, but with minimal pattern amplification. Some amplification is expected late Tuesday/early Wednesday across the Pacific Northwest, ahead of a strong shortwave trough approaching the coast. Surface pattern early Tuesday will feature high pressure centered over the central Appalachians and covering much of the OH Valley. This ridging is expected to gradually shift eastward/northeastward throughout the period. Surface troughing associated with the northern Plains shortwave trough will extend across the central Dakotas early Tuesday, before then shifting eastward throughout the day. Farther south across the northwest Gulf of Mexico, TC Francine is expected to reach hurricane strength while gradually progressing northeastward. ...TC Francine - LA Coast... Rainbands from Francine will likely spread across the northwest Gulf Coast throughout the day, but the stronger flow will remain displaced south throughout much of the period. Beginning around 06Z, the stronger flow may be far enough north to influence any deeper updrafts that develop along the LA Coast, with an attendant risk for brief tornadoes. ...Upper Midwest... Moderate low-level moisture, characterized by surface dewpoints in the upper 50s/low 60s, is expected across the region Tuesday afternoon ahead of the approaching shortwave trough and associated surface trough. Steep mid-level lapse rates will aid in the development of strong buoyancy across the region, supporting a conditional severe-thunderstorm risk. However, despite moderate low-level moisture and strong daytime heating, warm mid-level temperatures are forecast to keep capping in place, precluding afternoon thunderstorm development. ...Elsewhere... Afternoon thunderstorms are expected again across the eastern Great Basin and northern/central Rockies, where orographic effects and modest large-scale ascent will combine with modest moisture and buoyancy to support thunderstorm development. Increasing thunderstorm potential is anticipated late Tuesday into early Wednesday across the Pacific Northwest ahead of the approaching shortwave trough. ..Mosier/Lyons.. 09/10/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1233 AM CDT Tue Sep 10 2024 Valid 101200Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE LA COAST... ...SUMMARY... Some tornado threat associated with Tropical Cyclone Francine may approach the Louisiana Coast by early Wednesday morning. ...Synopsis... A shortwave trough is expected to be off the Northeast Coast early Tuesday morning, with continued eastward progression into the northern Atlantic expected thereafter. A relatively zonal pattern is anticipated west of this shortwave trough across the majority of the CONUS throughout much of the period. A low-amplitude shortwave trough is forecast to move within this zonal flow across the northern Plains and the Upper Midwest, but with minimal pattern amplification. Some amplification is expected late Tuesday/early Wednesday across the Pacific Northwest, ahead of a strong shortwave trough approaching the coast. Surface pattern early Tuesday will feature high pressure centered over the central Appalachians and covering much of the OH Valley. This ridging is expected to gradually shift eastward/northeastward throughout the period. Surface troughing associated with the northern Plains shortwave trough will extend across the central Dakotas early Tuesday, before then shifting eastward throughout the day. Farther south across the northwest Gulf of Mexico, TC Francine is expected to reach hurricane strength while gradually progressing northeastward. ...TC Francine - LA Coast... Rainbands from Francine will likely spread across the northwest Gulf Coast throughout the day, but the stronger flow will remain displaced south throughout much of the period. Beginning around 06Z, the stronger flow may be far enough north to influence any deeper updrafts that develop along the LA Coast, with an attendant risk for brief tornadoes. ...Upper Midwest... Moderate low-level moisture, characterized by surface dewpoints in the upper 50s/low 60s, is expected across the region Tuesday afternoon ahead of the approaching shortwave trough and associated surface trough. Steep mid-level lapse rates will aid in the development of strong buoyancy across the region, supporting a conditional severe-thunderstorm risk. However, despite moderate low-level moisture and strong daytime heating, warm mid-level temperatures are forecast to keep capping in place, precluding afternoon thunderstorm development. ...Elsewhere... Afternoon thunderstorms are expected again across the eastern Great Basin and northern/central Rockies, where orographic effects and modest large-scale ascent will combine with modest moisture and buoyancy to support thunderstorm development. Increasing thunderstorm potential is anticipated late Tuesday into early Wednesday across the Pacific Northwest ahead of the approaching shortwave trough. ..Mosier/Lyons.. 09/10/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0733 PM CDT Mon Sep 09 2024 Valid 100100Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected this evening and overnight. ...01Z Update... The overall severe threat across NY continues to decrease as the airmass stabilizes. Isolated thunderstorms will continue, but the reduced severe threat merits removal of the severe probabilities. Isolated thunderstorms will also remain possible from the Great Basin into the central Rockies/central High Plains this evening, before expanding eastward/northeastward into the central Plains and Mid MO Valley overnight into Wednesday morning. Lastly, thunderstorms will remain possible along the Gulf Coast and FL Peninsula. Highest coverage is anticipated across the TX Coast as rainbands associated TC Francine move across the region. Severe potential within these bands is expected to be very low. ..Mosier.. 09/10/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0733 PM CDT Mon Sep 09 2024 Valid 100100Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected this evening and overnight. ...01Z Update... The overall severe threat across NY continues to decrease as the airmass stabilizes. Isolated thunderstorms will continue, but the reduced severe threat merits removal of the severe probabilities. Isolated thunderstorms will also remain possible from the Great Basin into the central Rockies/central High Plains this evening, before expanding eastward/northeastward into the central Plains and Mid MO Valley overnight into Wednesday morning. Lastly, thunderstorms will remain possible along the Gulf Coast and FL Peninsula. Highest coverage is anticipated across the TX Coast as rainbands associated TC Francine move across the region. Severe potential within these bands is expected to be very low. ..Mosier.. 09/10/2024 Read more

No watches are valid as of Mon Sep 9 23:59:02 UTC 2024.

No Mesoscale Discussions are in effect as of Mon Sep 9 23:59:02 UTC 2024.

MD 2050 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WESTERN AND CENTRAL NEW YORK
Mesoscale Discussion 2050 NWS Storm Prediction Center Norman OK 0341 PM CDT Mon Sep 09 2024 Areas affected...Western and Central New York Concerning...Severe potential...Watch unlikely Valid 092041Z - 092215Z Probability of Watch Issuance...20 percent SUMMARY...Isolated strong to severe winds are possible with scattered thunderstorms across western and central New York. The transient and isolated nature of any severe storms will preclude watch issuance at this time. DISCUSSION...Scattered thunderstorms have moved onshore from Lake Ontario into New York, where the environment is characterized by relatively modest buoyancy of 500-1000 J/kg MUCAPE and 25-35 kts of deep-layer shear. Widespread cloudiness has limited daytime heating in the environment ahead of the convection, with surface temperatures mostly in the mid-to-upper 60s F. While shear and slight curvature of the hodograph will support transient storm organization, the overall severe wind threat will remain isolated and diminish after dark, and weather watch issuance is unlikely. ..Halbert/Gleason.. 09/09/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ALY...BGM...BUF... LAT...LON 42937947 43227925 43377871 43537769 43827664 44027604 43897563 43507479 43057468 42637471 42317496 42097529 42067554 42267734 42697927 42937947 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 09 2024 Valid 111200Z - 171200Z A potent upper-level trough will move through the Northwest and into the Great Basin by midweek. This trough will then lift northeastward with time before moving into the Canadian Prairie this coming weekend. Strong surface winds are expected along with and ahead of the trough as the surface pressure gradient increases in response. TC Francine will increase surface winds across parts of the Southeast/Mid-South where dry fuels exist. Another amplified upper trough is forecast to move into the West Coast by late this weekend into next week. Details of where dry/windy conditions will be or what mid-level moisture will be present remain uncertain at this time. ...Great Basin... A broad area of the Basin will likely experience critical fire weather on Wednesday. A deepening surface low/trough in parts of the eastern Basin will drive 15-25 mph winds over much of Nevada into western Utah. The mid-level jet will approach the northern Sierra and be roughly perpendicular to the terrain. At least a brief period of winds 25+ mph will be possible along with potentially intense wind gusts. RH in northwest Nevada will tend to see some improvement through the afternoon into the evening, but this is not expected to be significant enough to mitigate large fire potential. ...Northern/Central Plains... Fire weather concerns in parts of the Plains/High Plains will increase beginning Wednesday as the trough approaches and a surface low deepens first in eastern Montana and moving northward into the Canadian Prairie on Thursday. A lee trough will extend into the central High Plains. With preceding dry and windy days, fine fuels will continue to dry ahead of the increase in winds. Furthermore, it seems more likely than not that moisture return northward will be more limited than some guidance suggests (namely the ECMWF) especially with the stronger offshore winds developing around TC Francine. Winds will be stronger on Thursday given a stronger 850 mb jet that will last through the day. One point of uncertainty will be potential for storms to develop in the lee trough on Wednesday. That activity still appears to be quite isolated and should not have significant impact. Critical probabilities may need to be increased on Thursday depending on trends in guidance and updated fuel information. ...Mid-South... As TC Francine moves north and east, the surface pressure gradient inland should increase ahead of the cyclone. There is potential for at least locally elevated conditions in parts of the Mid-South on Wednesday as fuels in the region remain quite dry per latest ERC data. High cloud cover limits overall confidence in duration and magnitude of these conditions, however. ...Northern California... As the upper-level trough moves through the Great Basin, strong mid-level flow on the western flank of the trough will overspread northern California on Thursday. Additionally, surface high pressure will briefly build into the Northwest. Some north/northeasterly downslope winds are possible leading to some potentially locally elevated fire weather. The mid-level winds will be in the process of weakening through the day. Given the marginal conditions and likely limited duration, no highlights will be added. ..Wendt.. 09/09/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 09 2024 Valid 111200Z - 171200Z A potent upper-level trough will move through the Northwest and into the Great Basin by midweek. This trough will then lift northeastward with time before moving into the Canadian Prairie this coming weekend. Strong surface winds are expected along with and ahead of the trough as the surface pressure gradient increases in response. TC Francine will increase surface winds across parts of the Southeast/Mid-South where dry fuels exist. Another amplified upper trough is forecast to move into the West Coast by late this weekend into next week. Details of where dry/windy conditions will be or what mid-level moisture will be present remain uncertain at this time. ...Great Basin... A broad area of the Basin will likely experience critical fire weather on Wednesday. A deepening surface low/trough in parts of the eastern Basin will drive 15-25 mph winds over much of Nevada into western Utah. The mid-level jet will approach the northern Sierra and be roughly perpendicular to the terrain. At least a brief period of winds 25+ mph will be possible along with potentially intense wind gusts. RH in northwest Nevada will tend to see some improvement through the afternoon into the evening, but this is not expected to be significant enough to mitigate large fire potential. ...Northern/Central Plains... Fire weather concerns in parts of the Plains/High Plains will increase beginning Wednesday as the trough approaches and a surface low deepens first in eastern Montana and moving northward into the Canadian Prairie on Thursday. A lee trough will extend into the central High Plains. With preceding dry and windy days, fine fuels will continue to dry ahead of the increase in winds. Furthermore, it seems more likely than not that moisture return northward will be more limited than some guidance suggests (namely the ECMWF) especially with the stronger offshore winds developing around TC Francine. Winds will be stronger on Thursday given a stronger 850 mb jet that will last through the day. One point of uncertainty will be potential for storms to develop in the lee trough on Wednesday. That activity still appears to be quite isolated and should not have significant impact. Critical probabilities may need to be increased on Thursday depending on trends in guidance and updated fuel information. ...Mid-South... As TC Francine moves north and east, the surface pressure gradient inland should increase ahead of the cyclone. There is potential for at least locally elevated conditions in parts of the Mid-South on Wednesday as fuels in the region remain quite dry per latest ERC data. High cloud cover limits overall confidence in duration and magnitude of these conditions, however. ...Northern California... As the upper-level trough moves through the Great Basin, strong mid-level flow on the western flank of the trough will overspread northern California on Thursday. Additionally, surface high pressure will briefly build into the Northwest. Some north/northeasterly downslope winds are possible leading to some potentially locally elevated fire weather. The mid-level winds will be in the process of weakening through the day. Given the marginal conditions and likely limited duration, no highlights will be added. ..Wendt.. 09/09/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 09 2024 Valid 111200Z - 171200Z A potent upper-level trough will move through the Northwest and into the Great Basin by midweek. This trough will then lift northeastward with time before moving into the Canadian Prairie this coming weekend. Strong surface winds are expected along with and ahead of the trough as the surface pressure gradient increases in response. TC Francine will increase surface winds across parts of the Southeast/Mid-South where dry fuels exist. Another amplified upper trough is forecast to move into the West Coast by late this weekend into next week. Details of where dry/windy conditions will be or what mid-level moisture will be present remain uncertain at this time. ...Great Basin... A broad area of the Basin will likely experience critical fire weather on Wednesday. A deepening surface low/trough in parts of the eastern Basin will drive 15-25 mph winds over much of Nevada into western Utah. The mid-level jet will approach the northern Sierra and be roughly perpendicular to the terrain. At least a brief period of winds 25+ mph will be possible along with potentially intense wind gusts. RH in northwest Nevada will tend to see some improvement through the afternoon into the evening, but this is not expected to be significant enough to mitigate large fire potential. ...Northern/Central Plains... Fire weather concerns in parts of the Plains/High Plains will increase beginning Wednesday as the trough approaches and a surface low deepens first in eastern Montana and moving northward into the Canadian Prairie on Thursday. A lee trough will extend into the central High Plains. With preceding dry and windy days, fine fuels will continue to dry ahead of the increase in winds. Furthermore, it seems more likely than not that moisture return northward will be more limited than some guidance suggests (namely the ECMWF) especially with the stronger offshore winds developing around TC Francine. Winds will be stronger on Thursday given a stronger 850 mb jet that will last through the day. One point of uncertainty will be potential for storms to develop in the lee trough on Wednesday. That activity still appears to be quite isolated and should not have significant impact. Critical probabilities may need to be increased on Thursday depending on trends in guidance and updated fuel information. ...Mid-South... As TC Francine moves north and east, the surface pressure gradient inland should increase ahead of the cyclone. There is potential for at least locally elevated conditions in parts of the Mid-South on Wednesday as fuels in the region remain quite dry per latest ERC data. High cloud cover limits overall confidence in duration and magnitude of these conditions, however. ...Northern California... As the upper-level trough moves through the Great Basin, strong mid-level flow on the western flank of the trough will overspread northern California on Thursday. Additionally, surface high pressure will briefly build into the Northwest. Some north/northeasterly downslope winds are possible leading to some potentially locally elevated fire weather. The mid-level winds will be in the process of weakening through the day. Given the marginal conditions and likely limited duration, no highlights will be added. ..Wendt.. 09/09/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 09 2024 Valid 111200Z - 171200Z A potent upper-level trough will move through the Northwest and into the Great Basin by midweek. This trough will then lift northeastward with time before moving into the Canadian Prairie this coming weekend. Strong surface winds are expected along with and ahead of the trough as the surface pressure gradient increases in response. TC Francine will increase surface winds across parts of the Southeast/Mid-South where dry fuels exist. Another amplified upper trough is forecast to move into the West Coast by late this weekend into next week. Details of where dry/windy conditions will be or what mid-level moisture will be present remain uncertain at this time. ...Great Basin... A broad area of the Basin will likely experience critical fire weather on Wednesday. A deepening surface low/trough in parts of the eastern Basin will drive 15-25 mph winds over much of Nevada into western Utah. The mid-level jet will approach the northern Sierra and be roughly perpendicular to the terrain. At least a brief period of winds 25+ mph will be possible along with potentially intense wind gusts. RH in northwest Nevada will tend to see some improvement through the afternoon into the evening, but this is not expected to be significant enough to mitigate large fire potential. ...Northern/Central Plains... Fire weather concerns in parts of the Plains/High Plains will increase beginning Wednesday as the trough approaches and a surface low deepens first in eastern Montana and moving northward into the Canadian Prairie on Thursday. A lee trough will extend into the central High Plains. With preceding dry and windy days, fine fuels will continue to dry ahead of the increase in winds. Furthermore, it seems more likely than not that moisture return northward will be more limited than some guidance suggests (namely the ECMWF) especially with the stronger offshore winds developing around TC Francine. Winds will be stronger on Thursday given a stronger 850 mb jet that will last through the day. One point of uncertainty will be potential for storms to develop in the lee trough on Wednesday. That activity still appears to be quite isolated and should not have significant impact. Critical probabilities may need to be increased on Thursday depending on trends in guidance and updated fuel information. ...Mid-South... As TC Francine moves north and east, the surface pressure gradient inland should increase ahead of the cyclone. There is potential for at least locally elevated conditions in parts of the Mid-South on Wednesday as fuels in the region remain quite dry per latest ERC data. High cloud cover limits overall confidence in duration and magnitude of these conditions, however. ...Northern California... As the upper-level trough moves through the Great Basin, strong mid-level flow on the western flank of the trough will overspread northern California on Thursday. Additionally, surface high pressure will briefly build into the Northwest. Some north/northeasterly downslope winds are possible leading to some potentially locally elevated fire weather. The mid-level winds will be in the process of weakening through the day. Given the marginal conditions and likely limited duration, no highlights will be added. ..Wendt.. 09/09/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 09 2024 Valid 111200Z - 171200Z A potent upper-level trough will move through the Northwest and into the Great Basin by midweek. This trough will then lift northeastward with time before moving into the Canadian Prairie this coming weekend. Strong surface winds are expected along with and ahead of the trough as the surface pressure gradient increases in response. TC Francine will increase surface winds across parts of the Southeast/Mid-South where dry fuels exist. Another amplified upper trough is forecast to move into the West Coast by late this weekend into next week. Details of where dry/windy conditions will be or what mid-level moisture will be present remain uncertain at this time. ...Great Basin... A broad area of the Basin will likely experience critical fire weather on Wednesday. A deepening surface low/trough in parts of the eastern Basin will drive 15-25 mph winds over much of Nevada into western Utah. The mid-level jet will approach the northern Sierra and be roughly perpendicular to the terrain. At least a brief period of winds 25+ mph will be possible along with potentially intense wind gusts. RH in northwest Nevada will tend to see some improvement through the afternoon into the evening, but this is not expected to be significant enough to mitigate large fire potential. ...Northern/Central Plains... Fire weather concerns in parts of the Plains/High Plains will increase beginning Wednesday as the trough approaches and a surface low deepens first in eastern Montana and moving northward into the Canadian Prairie on Thursday. A lee trough will extend into the central High Plains. With preceding dry and windy days, fine fuels will continue to dry ahead of the increase in winds. Furthermore, it seems more likely than not that moisture return northward will be more limited than some guidance suggests (namely the ECMWF) especially with the stronger offshore winds developing around TC Francine. Winds will be stronger on Thursday given a stronger 850 mb jet that will last through the day. One point of uncertainty will be potential for storms to develop in the lee trough on Wednesday. That activity still appears to be quite isolated and should not have significant impact. Critical probabilities may need to be increased on Thursday depending on trends in guidance and updated fuel information. ...Mid-South... As TC Francine moves north and east, the surface pressure gradient inland should increase ahead of the cyclone. There is potential for at least locally elevated conditions in parts of the Mid-South on Wednesday as fuels in the region remain quite dry per latest ERC data. High cloud cover limits overall confidence in duration and magnitude of these conditions, however. ...Northern California... As the upper-level trough moves through the Great Basin, strong mid-level flow on the western flank of the trough will overspread northern California on Thursday. Additionally, surface high pressure will briefly build into the Northwest. Some north/northeasterly downslope winds are possible leading to some potentially locally elevated fire weather. The mid-level winds will be in the process of weakening through the day. Given the marginal conditions and likely limited duration, no highlights will be added. ..Wendt.. 09/09/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 09 2024 Valid 111200Z - 171200Z A potent upper-level trough will move through the Northwest and into the Great Basin by midweek. This trough will then lift northeastward with time before moving into the Canadian Prairie this coming weekend. Strong surface winds are expected along with and ahead of the trough as the surface pressure gradient increases in response. TC Francine will increase surface winds across parts of the Southeast/Mid-South where dry fuels exist. Another amplified upper trough is forecast to move into the West Coast by late this weekend into next week. Details of where dry/windy conditions will be or what mid-level moisture will be present remain uncertain at this time. ...Great Basin... A broad area of the Basin will likely experience critical fire weather on Wednesday. A deepening surface low/trough in parts of the eastern Basin will drive 15-25 mph winds over much of Nevada into western Utah. The mid-level jet will approach the northern Sierra and be roughly perpendicular to the terrain. At least a brief period of winds 25+ mph will be possible along with potentially intense wind gusts. RH in northwest Nevada will tend to see some improvement through the afternoon into the evening, but this is not expected to be significant enough to mitigate large fire potential. ...Northern/Central Plains... Fire weather concerns in parts of the Plains/High Plains will increase beginning Wednesday as the trough approaches and a surface low deepens first in eastern Montana and moving northward into the Canadian Prairie on Thursday. A lee trough will extend into the central High Plains. With preceding dry and windy days, fine fuels will continue to dry ahead of the increase in winds. Furthermore, it seems more likely than not that moisture return northward will be more limited than some guidance suggests (namely the ECMWF) especially with the stronger offshore winds developing around TC Francine. Winds will be stronger on Thursday given a stronger 850 mb jet that will last through the day. One point of uncertainty will be potential for storms to develop in the lee trough on Wednesday. That activity still appears to be quite isolated and should not have significant impact. Critical probabilities may need to be increased on Thursday depending on trends in guidance and updated fuel information. ...Mid-South... As TC Francine moves north and east, the surface pressure gradient inland should increase ahead of the cyclone. There is potential for at least locally elevated conditions in parts of the Mid-South on Wednesday as fuels in the region remain quite dry per latest ERC data. High cloud cover limits overall confidence in duration and magnitude of these conditions, however. ...Northern California... As the upper-level trough moves through the Great Basin, strong mid-level flow on the western flank of the trough will overspread northern California on Thursday. Additionally, surface high pressure will briefly build into the Northwest. Some north/northeasterly downslope winds are possible leading to some potentially locally elevated fire weather. The mid-level winds will be in the process of weakening through the day. Given the marginal conditions and likely limited duration, no highlights will be added. ..Wendt.. 09/09/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Mon Sep 09 2024 Valid 111200Z - 171200Z A potent upper-level trough will move through the Northwest and into the Great Basin by midweek. This trough will then lift northeastward with time before moving into the Canadian Prairie this coming weekend. Strong surface winds are expected along with and ahead of the trough as the surface pressure gradient increases in response. TC Francine will increase surface winds across parts of the Southeast/Mid-South where dry fuels exist. Another amplified upper trough is forecast to move into the West Coast by late this weekend into next week. Details of where dry/windy conditions will be or what mid-level moisture will be present remain uncertain at this time. ...Great Basin... A broad area of the Basin will likely experience critical fire weather on Wednesday. A deepening surface low/trough in parts of the eastern Basin will drive 15-25 mph winds over much of Nevada into western Utah. The mid-level jet will approach the northern Sierra and be roughly perpendicular to the terrain. At least a brief period of winds 25+ mph will be possible along with potentially intense wind gusts. RH in northwest Nevada will tend to see some improvement through the afternoon into the evening, but this is not expected to be significant enough to mitigate large fire potential. ...Northern/Central Plains... Fire weather concerns in parts of the Plains/High Plains will increase beginning Wednesday as the trough approaches and a surface low deepens first in eastern Montana and moving northward into the Canadian Prairie on Thursday. A lee trough will extend into the central High Plains. With preceding dry and windy days, fine fuels will continue to dry ahead of the increase in winds. Furthermore, it seems more likely than not that moisture return northward will be more limited than some guidance suggests (namely the ECMWF) especially with the stronger offshore winds developing around TC Francine. Winds will be stronger on Thursday given a stronger 850 mb jet that will last through the day. One point of uncertainty will be potential for storms to develop in the lee trough on Wednesday. That activity still appears to be quite isolated and should not have significant impact. Critical probabilities may need to be increased on Thursday depending on trends in guidance and updated fuel information. ...Mid-South... As TC Francine moves north and east, the surface pressure gradient inland should increase ahead of the cyclone. There is potential for at least locally elevated conditions in parts of the Mid-South on Wednesday as fuels in the region remain quite dry per latest ERC data. High cloud cover limits overall confidence in duration and magnitude of these conditions, however. ...Northern California... As the upper-level trough moves through the Great Basin, strong mid-level flow on the western flank of the trough will overspread northern California on Thursday. Additionally, surface high pressure will briefly build into the Northwest. Some north/northeasterly downslope winds are possible leading to some potentially locally elevated fire weather. The mid-level winds will be in the process of weakening through the day. Given the marginal conditions and likely limited duration, no highlights will be added. ..Wendt.. 09/09/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0234 PM CDT Mon Sep 09 2024 Valid 092000Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NEW YORK... ...SUMMARY... Isolated damaging winds remain possible this afternoon across parts of New York. ...20Z Update... No changes have been made to the Day 1 Convective Outlook. With storms continuing to increase in coverage and intensity over western NY, atop marginal boundary-layer-based instability, an instance or two of damaging gusts remain possible with one of the stronger storms. Similarly, a severe gust cannot be ruled out with one of the stronger storms over the Interior West given the presence of steep tropospheric lapse rates. Please see the previous outlook (below) for more details. ..Squitieri.. 09/09/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Sep 09 2024/ ...New York... Within large-scale upper troughing over the Northeast and eastern Canada, an embedded shortwave trough over southern Ontario and the upper Great Lakes will continue to move across the Northeast this afternoon and evening. Ascent associated with this shortwave trough and related mid-level jet is supporting isolated thunderstorms across southern Ontario and vicinity. This activity will spread east-southeastward this afternoon across parts of NY. The airmass over this region should become only weakly unstable as filtered daytime heating occurs, with poor mid-level lapse rates, persistent cloud cover, and modest low-level moisture limiting destabilization. Still, gradually increasing west-northwesterly winds at low/mid levels will foster around 25-35 kt of deep-layer shear. This should support modest thunderstorm organization, with multicells/small clusters potentially evolving along and downstream of Lake Ontario. Isolated strong to damaging winds should be the main threat with this convection as it moves across much of NY this afternoon and early evening, before eventually weakening with eastward extent with the loss of daytime heating. ...Northern/Central Rockies and High Plains... Isolated to widely scattered thunderstorms should develop this afternoon over portions of the northern/central Rockies as a weak shortwave trough continues eastward. Low-level moisture and related instability are both expected to remain rather meager into the High Plains, which should limit updraft intensities. Still, isolated strong/gusty winds may occur with this high-based activity across parts of MT/WY where low-level lapse rates can become steepened. Greater low-level moisture is present farther east into the Dakotas, along/east of a weak surface low/trough. But, increasing low/mid-level temperatures and a strong cap should generally inhibit thunderstorm development through much of the day with eastward extent across the northern/central Plains. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0234 PM CDT Mon Sep 09 2024 Valid 092000Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NEW YORK... ...SUMMARY... Isolated damaging winds remain possible this afternoon across parts of New York. ...20Z Update... No changes have been made to the Day 1 Convective Outlook. With storms continuing to increase in coverage and intensity over western NY, atop marginal boundary-layer-based instability, an instance or two of damaging gusts remain possible with one of the stronger storms. Similarly, a severe gust cannot be ruled out with one of the stronger storms over the Interior West given the presence of steep tropospheric lapse rates. Please see the previous outlook (below) for more details. ..Squitieri.. 09/09/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Sep 09 2024/ ...New York... Within large-scale upper troughing over the Northeast and eastern Canada, an embedded shortwave trough over southern Ontario and the upper Great Lakes will continue to move across the Northeast this afternoon and evening. Ascent associated with this shortwave trough and related mid-level jet is supporting isolated thunderstorms across southern Ontario and vicinity. This activity will spread east-southeastward this afternoon across parts of NY. The airmass over this region should become only weakly unstable as filtered daytime heating occurs, with poor mid-level lapse rates, persistent cloud cover, and modest low-level moisture limiting destabilization. Still, gradually increasing west-northwesterly winds at low/mid levels will foster around 25-35 kt of deep-layer shear. This should support modest thunderstorm organization, with multicells/small clusters potentially evolving along and downstream of Lake Ontario. Isolated strong to damaging winds should be the main threat with this convection as it moves across much of NY this afternoon and early evening, before eventually weakening with eastward extent with the loss of daytime heating. ...Northern/Central Rockies and High Plains... Isolated to widely scattered thunderstorms should develop this afternoon over portions of the northern/central Rockies as a weak shortwave trough continues eastward. Low-level moisture and related instability are both expected to remain rather meager into the High Plains, which should limit updraft intensities. Still, isolated strong/gusty winds may occur with this high-based activity across parts of MT/WY where low-level lapse rates can become steepened. Greater low-level moisture is present farther east into the Dakotas, along/east of a weak surface low/trough. But, increasing low/mid-level temperatures and a strong cap should generally inhibit thunderstorm development through much of the day with eastward extent across the northern/central Plains. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0234 PM CDT Mon Sep 09 2024 Valid 092000Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NEW YORK... ...SUMMARY... Isolated damaging winds remain possible this afternoon across parts of New York. ...20Z Update... No changes have been made to the Day 1 Convective Outlook. With storms continuing to increase in coverage and intensity over western NY, atop marginal boundary-layer-based instability, an instance or two of damaging gusts remain possible with one of the stronger storms. Similarly, a severe gust cannot be ruled out with one of the stronger storms over the Interior West given the presence of steep tropospheric lapse rates. Please see the previous outlook (below) for more details. ..Squitieri.. 09/09/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Sep 09 2024/ ...New York... Within large-scale upper troughing over the Northeast and eastern Canada, an embedded shortwave trough over southern Ontario and the upper Great Lakes will continue to move across the Northeast this afternoon and evening. Ascent associated with this shortwave trough and related mid-level jet is supporting isolated thunderstorms across southern Ontario and vicinity. This activity will spread east-southeastward this afternoon across parts of NY. The airmass over this region should become only weakly unstable as filtered daytime heating occurs, with poor mid-level lapse rates, persistent cloud cover, and modest low-level moisture limiting destabilization. Still, gradually increasing west-northwesterly winds at low/mid levels will foster around 25-35 kt of deep-layer shear. This should support modest thunderstorm organization, with multicells/small clusters potentially evolving along and downstream of Lake Ontario. Isolated strong to damaging winds should be the main threat with this convection as it moves across much of NY this afternoon and early evening, before eventually weakening with eastward extent with the loss of daytime heating. ...Northern/Central Rockies and High Plains... Isolated to widely scattered thunderstorms should develop this afternoon over portions of the northern/central Rockies as a weak shortwave trough continues eastward. Low-level moisture and related instability are both expected to remain rather meager into the High Plains, which should limit updraft intensities. Still, isolated strong/gusty winds may occur with this high-based activity across parts of MT/WY where low-level lapse rates can become steepened. Greater low-level moisture is present farther east into the Dakotas, along/east of a weak surface low/trough. But, increasing low/mid-level temperatures and a strong cap should generally inhibit thunderstorm development through much of the day with eastward extent across the northern/central Plains. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0234 PM CDT Mon Sep 09 2024 Valid 092000Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF NEW YORK... ...SUMMARY... Isolated damaging winds remain possible this afternoon across parts of New York. ...20Z Update... No changes have been made to the Day 1 Convective Outlook. With storms continuing to increase in coverage and intensity over western NY, atop marginal boundary-layer-based instability, an instance or two of damaging gusts remain possible with one of the stronger storms. Similarly, a severe gust cannot be ruled out with one of the stronger storms over the Interior West given the presence of steep tropospheric lapse rates. Please see the previous outlook (below) for more details. ..Squitieri.. 09/09/2024 .PREV DISCUSSION... /ISSUED 1126 AM CDT Mon Sep 09 2024/ ...New York... Within large-scale upper troughing over the Northeast and eastern Canada, an embedded shortwave trough over southern Ontario and the upper Great Lakes will continue to move across the Northeast this afternoon and evening. Ascent associated with this shortwave trough and related mid-level jet is supporting isolated thunderstorms across southern Ontario and vicinity. This activity will spread east-southeastward this afternoon across parts of NY. The airmass over this region should become only weakly unstable as filtered daytime heating occurs, with poor mid-level lapse rates, persistent cloud cover, and modest low-level moisture limiting destabilization. Still, gradually increasing west-northwesterly winds at low/mid levels will foster around 25-35 kt of deep-layer shear. This should support modest thunderstorm organization, with multicells/small clusters potentially evolving along and downstream of Lake Ontario. Isolated strong to damaging winds should be the main threat with this convection as it moves across much of NY this afternoon and early evening, before eventually weakening with eastward extent with the loss of daytime heating. ...Northern/Central Rockies and High Plains... Isolated to widely scattered thunderstorms should develop this afternoon over portions of the northern/central Rockies as a weak shortwave trough continues eastward. Low-level moisture and related instability are both expected to remain rather meager into the High Plains, which should limit updraft intensities. Still, isolated strong/gusty winds may occur with this high-based activity across parts of MT/WY where low-level lapse rates can become steepened. Greater low-level moisture is present farther east into the Dakotas, along/east of a weak surface low/trough. But, increasing low/mid-level temperatures and a strong cap should generally inhibit thunderstorm development through much of the day with eastward extent across the northern/central Plains. Read more