Severe Storms

No Mesoscale Discussions are in effect as of Fri Aug 9 22:53:03 UTC 2024.

WW 0617 Status Updates
STATUS REPORT ON WW 617 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NNE TTN TO 20 E ALB TO 15 WSW MPV. ..BROYLES..08/09/24 ATTN...WFO...BOX...ALY...OKX...PHI...BGM...BTV... STATUS REPORT FOR WT 617 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC003-005-092340- CT . CONNECTICUT COUNTIES INCLUDED ARE HARTFORD LITCHFIELD MAC003-011-013-015-092340- MA . MASSACHUSETTS COUNTIES INCLUDED ARE BERKSHIRE FRANKLIN HAMPDEN HAMPSHIRE NJC003-013-031-039-092340- NJ . NEW JERSEY COUNTIES INCLUDED ARE BERGEN ESSEX PASSAIC UNION Read more

WW 617 TORNADO CT MA NJ NY PA VT 091725Z - 100200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 617 NWS Storm Prediction Center Norman OK 125 PM EDT Fri Aug 9 2024 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of western Connecticut western Massachusetts parts of central and northern New Jersey eastern New York eastern Pennsylvania central and southern Vermont * Effective this Friday afternoon and evening from 125 PM until 1000 PM EDT. * Primary threats include... A couple tornadoes possible Isolated damaging wind gusts to 65 mph possible SUMMARY...As extra-tropical cyclone Debby continues moving northeastward across eastern New York this afternoon and into this evening, potential for a few tornadoes will accompany this system -- affecting areas as far east as western New England. The tornado watch area is approximately along and 55 statute miles east and west of a line from 40 miles northwest of Rutland VT to 65 miles south of Monticello NY. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 616... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 0.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 18040. ...Goss Read more

MD 1875 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHERN/CENTRAL WY INTO EXTREME NORTHEAST UT/SOUTHEAST ID
Mesoscale Discussion 1875 NWS Storm Prediction Center Norman OK 0351 PM CDT Fri Aug 09 2024 Areas affected...Parts of southern/central WY into extreme northeast UT/southeast ID Concerning...Severe potential...Watch unlikely Valid 092051Z - 092245Z Probability of Watch Issuance...20 percent SUMMARY...Isolated strong to severe gusts will be possible from late afternoon into the early evening. DISCUSSION...Multiple areas of building cumulus are noted across parts of southern/central WY this afternoon, with a strong storm over far northern UT. While low-level moisture remains rather modest, a combination of diurnal heating and relatively steep lapse rates have resulted in modest destabilization, with MLCAPE increasing to near or above 500 J/kg across much of the region. Generally unidirectional wind profiles with moderate westerly midlevel flow are supporting effective shear of 30-40 kt, sufficient for modestly organized cells/clusters as storms mature. Initial storms could pose a nonzero hail threat, but one or more outflow-driven clusters may evolve with time, as storms move through a well-mixed environment. Steep low-level lapse rates will support potential for strong to locally severe gusts as convection spreads eastward from late afternoon into the early evening. ..Dean/Goss.. 08/09/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CYS...RIW...SLC...PIH... LAT...LON 41150838 41141054 41291092 41591169 42151169 42971069 43470985 43360752 43310709 42960589 42190559 41490554 41120557 41070616 41170738 41150838 Read more

MD 1876 CONCERNING TORNADO WATCH 617... FOR PORTIONS OF EASTERN NY...SOUTHERN VT...AND WESTERN MA
Mesoscale Discussion 1876 NWS Storm Prediction Center Norman OK 0357 PM CDT Fri Aug 09 2024 Areas affected...Portions of eastern NY...southern VT...and western MA Concerning...Tornado Watch 617... Valid 092057Z - 092230Z The severe weather threat for Tornado Watch 617 continues. SUMMARY...Locally damaging gusts and perhaps a tornado or two remain possible across portions of Tornado Watch 617 in this evening. DISCUSSION...A band of low-topped thunderstorms is tracking eastward across portions of eastern NY this afternoon, though weak instability has generally limited updraft intensity thus far. However, very strong west-southwesterly deep-layer flow/shear could still support locally damaging gusts if any updrafts within the line are able to mature. And, with around 400 m2/s2 effective SRH ahead of the convection, a brief tornado or two cannot be ruled out. ..Weinman.. 08/09/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BOX...BTV...ALY... LAT...LON 42307386 42597375 43197349 43647381 43747366 43797335 43607285 43327261 42627275 42147321 42107373 42307386 Read more

WW 0617 Status Updates
STATUS REPORT ON WW 617 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 E ABE TO 20 SSW GFL TO 35 SW SLK. ..BROYLES..08/09/24 ATTN...WFO...BOX...ALY...OKX...PHI...BGM...BTV... STATUS REPORT FOR WT 617 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC003-005-092240- CT . CONNECTICUT COUNTIES INCLUDED ARE HARTFORD LITCHFIELD MAC003-011-013-015-092240- MA . MASSACHUSETTS COUNTIES INCLUDED ARE BERKSHIRE FRANKLIN HAMPDEN HAMPSHIRE NJC003-013-031-039-092240- NJ . NEW JERSEY COUNTIES INCLUDED ARE BERGEN ESSEX PASSAIC UNION Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0332 PM CDT Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 Fri Aug 09 2024 Valid 111200Z - 171200Z Fire weather concerns will primarily remain focused across portions of the Great Basin through the extended period. Long-range ensemble guidance shows reasonably good agreement the gradual amplification of the upper-level synoptic regime over the next seven days. This will be characterized by ridging across the central CONUS with mean troughing along the West Coast. West/southwesterly flow over the Great Basin will allow multiple short-wave disturbances to propagate across the West with frequent rain/thunderstorm chances across the Four Corners amid a continued northward flux of monsoonal moisture from the Gulf of California. However, ensemble guidance suggest predominantly dry conditions will persist across NV, CA, and southeast OR/southwest ID. This will maintain dry fuels as winds increase with each passing upper disturbance. Some solutions (notably recent GFS and GEFS runs) suggest localized elevated conditions will be possible each day across southern CA into much of NV, though confidence in somewhat more widespread elevated conditions (with perhaps some critical conditions) remains highest on D4/Monday when a progressive shortwave moves across the region. ..Moore.. 08/09/2024 ...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 0253 PM CDT Fri Aug 09 2024 Valid 092000Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FAR EASTERN PA INTO NJ...EASTERN NY...AND WESTERN NEW ENGLAND... ...SUMMARY... A couple of tornadoes will be possible today from parts of the Mid-Atlantic states northward across portions of New England. A few strong wind gusts will also be possible across this region, along with parts of the southern High Plains, and southern Wyoming. ...20Z Update... Overall forecast reasoning remains valid. Post-TC Debby continues to progress northeastward across New York, with a band of deeper convection extending from just east of its center southward into far eastern PA/far western NJ. Area VADs show strong wind fields throughout the eastern portion of this cyclone, but limited buoyancy has tempered storm depth and persistence thus far. Given the robust wind fields, the potential for damaging gusts and/or brief tornadoes will persist throughout the afternoon and into the evening, particularly in areas ahead of the main convective line where more cellular storms are likely. Farther west, afternoon/evening thunderstorms are still possible across the higher terrain of WY, CO, and NM, with these storms then moving into the central/southern High Plains thereafter. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts. ..Mosier.. 08/09/2024 .PREV DISCUSSION... /ISSUED 1140 AM CDT Fri Aug 09 2024/ ...Portions of the Mid-Atlantic and New England... As the center of P.T.C. Debby -- now over south-central New York -- continues moving north-northeastward across New York today, and then into Quebec/across the St. Lawrence Valley this evening and tonight, very strong low-level shear will continue to spread northward across eastern New York and much of New England. While northward destabilization will be hindered by a lack of appreciable daytime heating due to widespread cloud cover, a very moist boundary layer (dewpoints in the upper 60s to low 70s) spreading northward toward the Canadian border will support at least neutrally buoyant profiles across most of New England this evening and tonight. As such, low (2%) tornado probability is being expanded northward/northeastward in this update, to include the remainder of northern Vermont and northern New Hampshire, and much of Maine, to cover the potential for a brief tornadic spin-up after dark. Otherwise, greatest potential for a couple of tornadoes will exist this afternoon and into this evening from eastern Pennsylvania/eastern New York into parts of New Jersey, and across the Hudson and Champlain Valleys into western Vermont, western Massachusetts, and western Connecticut. ...Southern High Plains... Afternoon storm development is expected across the Raton Mesa vicinity of northeastern New Mexico, aided by afternoon heating/destabilization, and the eastward advance of a mid-level vort max across southern Colorado. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts as convection crosses the Oklahoma and northern Texas Panhandle area. ...Southern Wyoming... Daytime heating/modest destabilization across the Intermountain West will support development of isolated to scattered afternoon and evening thunderstorms. With a belt of moderate (30 to 40 kt) northwesterly flow across the Wyoming vicinity, some storm organization will be possible. Some CAMs suggest eventual upscale growth into a loosely organized cluster by this evening, moving east-southeastward toward southeastern portions of the state. Resulting potential for a few stronger wind gusts with this activity warrants inclusion of 5% wind probability/MRGL risk area. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 09 2024 Valid 092000Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FAR EASTERN PA INTO NJ...EASTERN NY...AND WESTERN NEW ENGLAND... ...SUMMARY... A couple of tornadoes will be possible today from parts of the Mid-Atlantic states northward across portions of New England. A few strong wind gusts will also be possible across this region, along with parts of the southern High Plains, and southern Wyoming. ...20Z Update... Overall forecast reasoning remains valid. Post-TC Debby continues to progress northeastward across New York, with a band of deeper convection extending from just east of its center southward into far eastern PA/far western NJ. Area VADs show strong wind fields throughout the eastern portion of this cyclone, but limited buoyancy has tempered storm depth and persistence thus far. Given the robust wind fields, the potential for damaging gusts and/or brief tornadoes will persist throughout the afternoon and into the evening, particularly in areas ahead of the main convective line where more cellular storms are likely. Farther west, afternoon/evening thunderstorms are still possible across the higher terrain of WY, CO, and NM, with these storms then moving into the central/southern High Plains thereafter. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts. ..Mosier.. 08/09/2024 .PREV DISCUSSION... /ISSUED 1140 AM CDT Fri Aug 09 2024/ ...Portions of the Mid-Atlantic and New England... As the center of P.T.C. Debby -- now over south-central New York -- continues moving north-northeastward across New York today, and then into Quebec/across the St. Lawrence Valley this evening and tonight, very strong low-level shear will continue to spread northward across eastern New York and much of New England. While northward destabilization will be hindered by a lack of appreciable daytime heating due to widespread cloud cover, a very moist boundary layer (dewpoints in the upper 60s to low 70s) spreading northward toward the Canadian border will support at least neutrally buoyant profiles across most of New England this evening and tonight. As such, low (2%) tornado probability is being expanded northward/northeastward in this update, to include the remainder of northern Vermont and northern New Hampshire, and much of Maine, to cover the potential for a brief tornadic spin-up after dark. Otherwise, greatest potential for a couple of tornadoes will exist this afternoon and into this evening from eastern Pennsylvania/eastern New York into parts of New Jersey, and across the Hudson and Champlain Valleys into western Vermont, western Massachusetts, and western Connecticut. ...Southern High Plains... Afternoon storm development is expected across the Raton Mesa vicinity of northeastern New Mexico, aided by afternoon heating/destabilization, and the eastward advance of a mid-level vort max across southern Colorado. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts as convection crosses the Oklahoma and northern Texas Panhandle area. ...Southern Wyoming... Daytime heating/modest destabilization across the Intermountain West will support development of isolated to scattered afternoon and evening thunderstorms. With a belt of moderate (30 to 40 kt) northwesterly flow across the Wyoming vicinity, some storm organization will be possible. Some CAMs suggest eventual upscale growth into a loosely organized cluster by this evening, moving east-southeastward toward southeastern portions of the state. Resulting potential for a few stronger wind gusts with this activity warrants inclusion of 5% wind probability/MRGL risk area. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Fri Aug 09 2024 Valid 092000Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM FAR EASTERN PA INTO NJ...EASTERN NY...AND WESTERN NEW ENGLAND... ...SUMMARY... A couple of tornadoes will be possible today from parts of the Mid-Atlantic states northward across portions of New England. A few strong wind gusts will also be possible across this region, along with parts of the southern High Plains, and southern Wyoming. ...20Z Update... Overall forecast reasoning remains valid. Post-TC Debby continues to progress northeastward across New York, with a band of deeper convection extending from just east of its center southward into far eastern PA/far western NJ. Area VADs show strong wind fields throughout the eastern portion of this cyclone, but limited buoyancy has tempered storm depth and persistence thus far. Given the robust wind fields, the potential for damaging gusts and/or brief tornadoes will persist throughout the afternoon and into the evening, particularly in areas ahead of the main convective line where more cellular storms are likely. Farther west, afternoon/evening thunderstorms are still possible across the higher terrain of WY, CO, and NM, with these storms then moving into the central/southern High Plains thereafter. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts. ..Mosier.. 08/09/2024 .PREV DISCUSSION... /ISSUED 1140 AM CDT Fri Aug 09 2024/ ...Portions of the Mid-Atlantic and New England... As the center of P.T.C. Debby -- now over south-central New York -- continues moving north-northeastward across New York today, and then into Quebec/across the St. Lawrence Valley this evening and tonight, very strong low-level shear will continue to spread northward across eastern New York and much of New England. While northward destabilization will be hindered by a lack of appreciable daytime heating due to widespread cloud cover, a very moist boundary layer (dewpoints in the upper 60s to low 70s) spreading northward toward the Canadian border will support at least neutrally buoyant profiles across most of New England this evening and tonight. As such, low (2%) tornado probability is being expanded northward/northeastward in this update, to include the remainder of northern Vermont and northern New Hampshire, and much of Maine, to cover the potential for a brief tornadic spin-up after dark. Otherwise, greatest potential for a couple of tornadoes will exist this afternoon and into this evening from eastern Pennsylvania/eastern New York into parts of New Jersey, and across the Hudson and Champlain Valleys into western Vermont, western Massachusetts, and western Connecticut. ...Southern High Plains... Afternoon storm development is expected across the Raton Mesa vicinity of northeastern New Mexico, aided by afternoon heating/destabilization, and the eastward advance of a mid-level vort max across southern Colorado. Moderate (around 30 kt) mid-level westerlies may support some organization/upscale growth of storms into the evening, along with accompanying potential for a couple of strong gusts as convection crosses the Oklahoma and northern Texas Panhandle area. ...Southern Wyoming... Daytime heating/modest destabilization across the Intermountain West will support development of isolated to scattered afternoon and evening thunderstorms. With a belt of moderate (30 to 40 kt) northwesterly flow across the Wyoming vicinity, some storm organization will be possible. Some CAMs suggest eventual upscale growth into a loosely organized cluster by this evening, moving east-southeastward toward southeastern portions of the state. Resulting potential for a few stronger wind gusts with this activity warrants inclusion of 5% wind probability/MRGL risk area. Read more