Aggregator

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 PM CDT Sat Aug 31 2024 Valid 010100Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN GREAT LAKES... ...SUMMARY... Isolated severe wind gusts will be possible this evening across parts of the northern Great Lakes. ...Northern Great Lakes... Water vapor imagery shows a low-amplitude shortwave trough over southern Ontario extending into northern Minnesota. Ahead of the shortwave trough, a band of large-scale ascent appears to be moving through the vicinity of Lake Superior, where a broken line of thunderstorms is ongoing. Ahead of this line, surface dewpoints are in the mid 50s F, and the RAP has SBCAPE of 250 to 500 J/kg. RAP forecast soundings over upper Michigan have strong deep-layer shear exceeding 60 knots, and steep low to mid-level lapse rates. This may be enough for an isolated threat of severe wind gusts. This threat may persist for another hour or two. ..Broyles.. 09/01/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 PM CDT Sat Aug 31 2024 Valid 010100Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN GREAT LAKES... ...SUMMARY... Isolated severe wind gusts will be possible this evening across parts of the northern Great Lakes. ...Northern Great Lakes... Water vapor imagery shows a low-amplitude shortwave trough over southern Ontario extending into northern Minnesota. Ahead of the shortwave trough, a band of large-scale ascent appears to be moving through the vicinity of Lake Superior, where a broken line of thunderstorms is ongoing. Ahead of this line, surface dewpoints are in the mid 50s F, and the RAP has SBCAPE of 250 to 500 J/kg. RAP forecast soundings over upper Michigan have strong deep-layer shear exceeding 60 knots, and steep low to mid-level lapse rates. This may be enough for an isolated threat of severe wind gusts. This threat may persist for another hour or two. ..Broyles.. 09/01/2024 Read more

000
ABPZ20 KNHC 312324
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Sat Aug 31 2024

For the eastern North Pacific...east of 140 degrees west longitude:

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Beven

No watches are valid as of Sat Aug 31 23:02:01 UTC 2024.

No Mesoscale Discussions are in effect as of Sat Aug 31 23:02:01 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0448 PM CDT Sat Aug 31 2024 Valid 021200Z - 081200Z A midlevel trough will move across northern CA/southwest OR and continue east-northeastward across OR into ID D2/Sun through D3/Monday. Ahead of this feature, an increase in moisture and ascent will support potential for isolated dry thunderstorms across the Pacific Northwest extending into the Northern Rockies. As a mid-level speed max moves through the trough, an increase in surface winds is expected D3/Monday to D4/Tuesday, overlapping very dry antecedent conditions across portions of the Great Basin. Beyond D4/Tuesday, high pressure will build back in across the western US, with a warming and drying trend. Monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest. Winds will remain mostly light where fuels are dry keeping fire weather concerns low. ...Dry/Windy... Surface winds will increase across northern Nevada into northeastern California and southern Oregon on D3/Monday as a speed max moves through the base of the midlevel trough. Sustained west southwesterly winds at 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent. The highest confidence in overlap of fuels and windy/dry conditions will be across northwestern Nevada into far northeastern California, where 70% probabilities were maintained in this outlook. Dry and windy conditions will continue eastward into portions of southern Idaho and the Northern Rockies on D4/Tuesday. The highest confidence for potential Critical conditions will be across the Snake River Plain, where a 40 percent delineation was maintained with this outlook. ...Isolated Dry Thunderstorms... A mix of dry/wet thunderstorms will be possible overnight across eastern Oregon into Idaho D2/Sunday into D3/Monday as the trough and accent shift north and eastward. Several days of boundary-layer drying (beneath the large-scale ridge) preceding this thunderstorm event has made fuels receptive and will pose at least some risk of lightning-induced ignitions. Thunderstorm potential will continue across the northern Rockies on Day 4/Tuesday, though gradually increasing moisture and precipitation cast uncertainty on the overall fire-weather risk which precluding Isolated Dry Thunderstorm probabilities. ..Thornton.. 08/31/2024 ...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 0448 PM CDT Sat Aug 31 2024 Valid 021200Z - 081200Z A midlevel trough will move across northern CA/southwest OR and continue east-northeastward across OR into ID D2/Sun through D3/Monday. Ahead of this feature, an increase in moisture and ascent will support potential for isolated dry thunderstorms across the Pacific Northwest extending into the Northern Rockies. As a mid-level speed max moves through the trough, an increase in surface winds is expected D3/Monday to D4/Tuesday, overlapping very dry antecedent conditions across portions of the Great Basin. Beyond D4/Tuesday, high pressure will build back in across the western US, with a warming and drying trend. Monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest. Winds will remain mostly light where fuels are dry keeping fire weather concerns low. ...Dry/Windy... Surface winds will increase across northern Nevada into northeastern California and southern Oregon on D3/Monday as a speed max moves through the base of the midlevel trough. Sustained west southwesterly winds at 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent. The highest confidence in overlap of fuels and windy/dry conditions will be across northwestern Nevada into far northeastern California, where 70% probabilities were maintained in this outlook. Dry and windy conditions will continue eastward into portions of southern Idaho and the Northern Rockies on D4/Tuesday. The highest confidence for potential Critical conditions will be across the Snake River Plain, where a 40 percent delineation was maintained with this outlook. ...Isolated Dry Thunderstorms... A mix of dry/wet thunderstorms will be possible overnight across eastern Oregon into Idaho D2/Sunday into D3/Monday as the trough and accent shift north and eastward. Several days of boundary-layer drying (beneath the large-scale ridge) preceding this thunderstorm event has made fuels receptive and will pose at least some risk of lightning-induced ignitions. Thunderstorm potential will continue across the northern Rockies on Day 4/Tuesday, though gradually increasing moisture and precipitation cast uncertainty on the overall fire-weather risk which precluding Isolated Dry Thunderstorm probabilities. ..Thornton.. 08/31/2024 ...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 0448 PM CDT Sat Aug 31 2024 Valid 021200Z - 081200Z A midlevel trough will move across northern CA/southwest OR and continue east-northeastward across OR into ID D2/Sun through D3/Monday. Ahead of this feature, an increase in moisture and ascent will support potential for isolated dry thunderstorms across the Pacific Northwest extending into the Northern Rockies. As a mid-level speed max moves through the trough, an increase in surface winds is expected D3/Monday to D4/Tuesday, overlapping very dry antecedent conditions across portions of the Great Basin. Beyond D4/Tuesday, high pressure will build back in across the western US, with a warming and drying trend. Monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest. Winds will remain mostly light where fuels are dry keeping fire weather concerns low. ...Dry/Windy... Surface winds will increase across northern Nevada into northeastern California and southern Oregon on D3/Monday as a speed max moves through the base of the midlevel trough. Sustained west southwesterly winds at 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent. The highest confidence in overlap of fuels and windy/dry conditions will be across northwestern Nevada into far northeastern California, where 70% probabilities were maintained in this outlook. Dry and windy conditions will continue eastward into portions of southern Idaho and the Northern Rockies on D4/Tuesday. The highest confidence for potential Critical conditions will be across the Snake River Plain, where a 40 percent delineation was maintained with this outlook. ...Isolated Dry Thunderstorms... A mix of dry/wet thunderstorms will be possible overnight across eastern Oregon into Idaho D2/Sunday into D3/Monday as the trough and accent shift north and eastward. Several days of boundary-layer drying (beneath the large-scale ridge) preceding this thunderstorm event has made fuels receptive and will pose at least some risk of lightning-induced ignitions. Thunderstorm potential will continue across the northern Rockies on Day 4/Tuesday, though gradually increasing moisture and precipitation cast uncertainty on the overall fire-weather risk which precluding Isolated Dry Thunderstorm probabilities. ..Thornton.. 08/31/2024 ...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 0448 PM CDT Sat Aug 31 2024 Valid 021200Z - 081200Z A midlevel trough will move across northern CA/southwest OR and continue east-northeastward across OR into ID D2/Sun through D3/Monday. Ahead of this feature, an increase in moisture and ascent will support potential for isolated dry thunderstorms across the Pacific Northwest extending into the Northern Rockies. As a mid-level speed max moves through the trough, an increase in surface winds is expected D3/Monday to D4/Tuesday, overlapping very dry antecedent conditions across portions of the Great Basin. Beyond D4/Tuesday, high pressure will build back in across the western US, with a warming and drying trend. Monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest. Winds will remain mostly light where fuels are dry keeping fire weather concerns low. ...Dry/Windy... Surface winds will increase across northern Nevada into northeastern California and southern Oregon on D3/Monday as a speed max moves through the base of the midlevel trough. Sustained west southwesterly winds at 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent. The highest confidence in overlap of fuels and windy/dry conditions will be across northwestern Nevada into far northeastern California, where 70% probabilities were maintained in this outlook. Dry and windy conditions will continue eastward into portions of southern Idaho and the Northern Rockies on D4/Tuesday. The highest confidence for potential Critical conditions will be across the Snake River Plain, where a 40 percent delineation was maintained with this outlook. ...Isolated Dry Thunderstorms... A mix of dry/wet thunderstorms will be possible overnight across eastern Oregon into Idaho D2/Sunday into D3/Monday as the trough and accent shift north and eastward. Several days of boundary-layer drying (beneath the large-scale ridge) preceding this thunderstorm event has made fuels receptive and will pose at least some risk of lightning-induced ignitions. Thunderstorm potential will continue across the northern Rockies on Day 4/Tuesday, though gradually increasing moisture and precipitation cast uncertainty on the overall fire-weather risk which precluding Isolated Dry Thunderstorm probabilities. ..Thornton.. 08/31/2024 ...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 0448 PM CDT Sat Aug 31 2024 Valid 021200Z - 081200Z A midlevel trough will move across northern CA/southwest OR and continue east-northeastward across OR into ID D2/Sun through D3/Monday. Ahead of this feature, an increase in moisture and ascent will support potential for isolated dry thunderstorms across the Pacific Northwest extending into the Northern Rockies. As a mid-level speed max moves through the trough, an increase in surface winds is expected D3/Monday to D4/Tuesday, overlapping very dry antecedent conditions across portions of the Great Basin. Beyond D4/Tuesday, high pressure will build back in across the western US, with a warming and drying trend. Monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest. Winds will remain mostly light where fuels are dry keeping fire weather concerns low. ...Dry/Windy... Surface winds will increase across northern Nevada into northeastern California and southern Oregon on D3/Monday as a speed max moves through the base of the midlevel trough. Sustained west southwesterly winds at 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent. The highest confidence in overlap of fuels and windy/dry conditions will be across northwestern Nevada into far northeastern California, where 70% probabilities were maintained in this outlook. Dry and windy conditions will continue eastward into portions of southern Idaho and the Northern Rockies on D4/Tuesday. The highest confidence for potential Critical conditions will be across the Snake River Plain, where a 40 percent delineation was maintained with this outlook. ...Isolated Dry Thunderstorms... A mix of dry/wet thunderstorms will be possible overnight across eastern Oregon into Idaho D2/Sunday into D3/Monday as the trough and accent shift north and eastward. Several days of boundary-layer drying (beneath the large-scale ridge) preceding this thunderstorm event has made fuels receptive and will pose at least some risk of lightning-induced ignitions. Thunderstorm potential will continue across the northern Rockies on Day 4/Tuesday, though gradually increasing moisture and precipitation cast uncertainty on the overall fire-weather risk which precluding Isolated Dry Thunderstorm probabilities. ..Thornton.. 08/31/2024 ...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 0448 PM CDT Sat Aug 31 2024 Valid 021200Z - 081200Z A midlevel trough will move across northern CA/southwest OR and continue east-northeastward across OR into ID D2/Sun through D3/Monday. Ahead of this feature, an increase in moisture and ascent will support potential for isolated dry thunderstorms across the Pacific Northwest extending into the Northern Rockies. As a mid-level speed max moves through the trough, an increase in surface winds is expected D3/Monday to D4/Tuesday, overlapping very dry antecedent conditions across portions of the Great Basin. Beyond D4/Tuesday, high pressure will build back in across the western US, with a warming and drying trend. Monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest. Winds will remain mostly light where fuels are dry keeping fire weather concerns low. ...Dry/Windy... Surface winds will increase across northern Nevada into northeastern California and southern Oregon on D3/Monday as a speed max moves through the base of the midlevel trough. Sustained west southwesterly winds at 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent. The highest confidence in overlap of fuels and windy/dry conditions will be across northwestern Nevada into far northeastern California, where 70% probabilities were maintained in this outlook. Dry and windy conditions will continue eastward into portions of southern Idaho and the Northern Rockies on D4/Tuesday. The highest confidence for potential Critical conditions will be across the Snake River Plain, where a 40 percent delineation was maintained with this outlook. ...Isolated Dry Thunderstorms... A mix of dry/wet thunderstorms will be possible overnight across eastern Oregon into Idaho D2/Sunday into D3/Monday as the trough and accent shift north and eastward. Several days of boundary-layer drying (beneath the large-scale ridge) preceding this thunderstorm event has made fuels receptive and will pose at least some risk of lightning-induced ignitions. Thunderstorm potential will continue across the northern Rockies on Day 4/Tuesday, though gradually increasing moisture and precipitation cast uncertainty on the overall fire-weather risk which precluding Isolated Dry Thunderstorm probabilities. ..Thornton.. 08/31/2024 ...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 0448 PM CDT Sat Aug 31 2024 Valid 021200Z - 081200Z A midlevel trough will move across northern CA/southwest OR and continue east-northeastward across OR into ID D2/Sun through D3/Monday. Ahead of this feature, an increase in moisture and ascent will support potential for isolated dry thunderstorms across the Pacific Northwest extending into the Northern Rockies. As a mid-level speed max moves through the trough, an increase in surface winds is expected D3/Monday to D4/Tuesday, overlapping very dry antecedent conditions across portions of the Great Basin. Beyond D4/Tuesday, high pressure will build back in across the western US, with a warming and drying trend. Monsoonal moisture will gradually shift southward with drying conditions extending into the desert Southwest. Winds will remain mostly light where fuels are dry keeping fire weather concerns low. ...Dry/Windy... Surface winds will increase across northern Nevada into northeastern California and southern Oregon on D3/Monday as a speed max moves through the base of the midlevel trough. Sustained west southwesterly winds at 15-20 mph will overlap afternoon relative humidity reductions to 10-15 percent. The highest confidence in overlap of fuels and windy/dry conditions will be across northwestern Nevada into far northeastern California, where 70% probabilities were maintained in this outlook. Dry and windy conditions will continue eastward into portions of southern Idaho and the Northern Rockies on D4/Tuesday. The highest confidence for potential Critical conditions will be across the Snake River Plain, where a 40 percent delineation was maintained with this outlook. ...Isolated Dry Thunderstorms... A mix of dry/wet thunderstorms will be possible overnight across eastern Oregon into Idaho D2/Sunday into D3/Monday as the trough and accent shift north and eastward. Several days of boundary-layer drying (beneath the large-scale ridge) preceding this thunderstorm event has made fuels receptive and will pose at least some risk of lightning-induced ignitions. Thunderstorm potential will continue across the northern Rockies on Day 4/Tuesday, though gradually increasing moisture and precipitation cast uncertainty on the overall fire-weather risk which precluding Isolated Dry Thunderstorm probabilities. ..Thornton.. 08/31/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0666 Status Updates
STATUS REPORT ON WW 666 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 NNW PKB TO 30 N SHD TO 20 NW HGR. ..MOORE..08/31/24 ATTN...WFO...LWX...PBZ...CTP...RNK...RLX... STATUS REPORT FOR WS 666 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MDC043-312240- MD . MARYLAND COUNTIES INCLUDED ARE WASHINGTON VAC005-017-019-023-043-045-067-069-091-139-163-165-171-187-530- 580-660-678-770-775-790-820-840-312240- VA . VIRGINIA COUNTIES INCLUDED ARE ALLEGHANY BATH BEDFORD BOTETOURT CLARKE CRAIG FRANKLIN FREDERICK HIGHLAND PAGE ROCKBRIDGE ROCKINGHAM SHENANDOAH WARREN VIRGINIA INDEPENDENT CITIES INCLUDED ARE BUENA VISTA COVINGTON HARRISONBURG LEXINGTON ROANOKE SALEM Read more

WW 0666 Status Updates
STATUS REPORT ON WW 666 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 NNW PKB TO 30 N SHD TO 20 NW HGR. ..MOORE..08/31/24 ATTN...WFO...LWX...PBZ...CTP...RNK...RLX... STATUS REPORT FOR WS 666 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MDC043-312240- MD . MARYLAND COUNTIES INCLUDED ARE WASHINGTON VAC005-017-019-023-043-045-067-069-091-139-163-165-171-187-530- 580-660-678-770-775-790-820-840-312240- VA . VIRGINIA COUNTIES INCLUDED ARE ALLEGHANY BATH BEDFORD BOTETOURT CLARKE CRAIG FRANKLIN FREDERICK HIGHLAND PAGE ROCKBRIDGE ROCKINGHAM SHENANDOAH WARREN VIRGINIA INDEPENDENT CITIES INCLUDED ARE BUENA VISTA COVINGTON HARRISONBURG LEXINGTON ROANOKE SALEM Read more

WW 666 SEVERE TSTM MD PA VA WV 311725Z - 312300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 666 NWS Storm Prediction Center Norman OK 125 PM EDT Sat Aug 31 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western Maryland Southwest Pennsylvania Northwest Virginia West Virginia * Effective this Saturday afternoon and evening from 125 PM until 700 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms are expected to increase in coverage and move east across the watch area through the afternoon, posing a risk for scattered damaging wind gusts and isolated instances of large hail. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 40 miles northwest of Altoona PA to 10 miles southwest of Beckley WV. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 26025. ...Bunting Read more

WW 0666 Status Updates
STATUS REPORT ON WW 666 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 W HLG TO 20 N MGW TO 20 SE MGW TO 45 ESE MGW TO 25 SSE AOO AND 10 N PIT TO 30 ENE LBE TO 20 ESE UNV. ..WENDT..08/31/24 ATTN...WFO...LWX...PBZ...CTP...RNK...RLX... STATUS REPORT FOR WS 666 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MDC001-043-312140- MD . MARYLAND COUNTIES INCLUDED ARE ALLEGANY WASHINGTON PAC059-312140- PA . PENNSYLVANIA COUNTIES INCLUDED ARE GREENE VAC005-017-043-069-091-139-165-171-187-580-660-790-820-840- 312140- VA . VIRGINIA COUNTIES INCLUDED ARE ALLEGHANY BATH CLARKE FREDERICK HIGHLAND PAGE Read more

MD 2040 CONCERNING SEVERE THUNDERSTORM WATCH 666... FOR EASTERN WEST VIRGINIA...FAR NORTHWEST VIRGINIA...WESTERN MARYLAND...SOUTH-CENTRAL PENNSYLVANIA
Mesoscale Discussion 2040 NWS Storm Prediction Center Norman OK 0228 PM CDT Sat Aug 31 2024 Areas affected...Eastern West Virginia...far Northwest Virginia...western Maryland...south-central Pennsylvania Concerning...Severe Thunderstorm Watch 666... Valid 311928Z - 312130Z The severe weather threat for Severe Thunderstorm Watch 666 continues. SUMMARY...Wind damage will remain possible with the strongest storms as they continue east into the Appalachians. A gradual weakening trend is expected as they encounter a more stable environment. No additional watches are expected this afternoon. DISCUSSION...A broken line of semi-organized convection continues eastward into the Mid-Atlantic region this afternoon. The strongest cluster is currently located in south-central Pennsylvania. Scattered weaker storms are also evident within the Appalachians, ahead of the primary band of convection. These storms will likely act to limit storm intensity due to outflow cooling the airmass. Farther east, low-level cloud cover has remained entrenched up against the Blue Ridge. While wind damage will remain possible this afternoon, storms are expected to undergo gradual weakening with time as the environment is increasingly stable with eastward extent. No additional watches are expected this afternoon. ..Wendt.. 08/31/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CTP...LWX...RNK...PBZ...RLX... LAT...LON 37888020 38088101 38528119 39198038 39877954 40527842 40447805 40007788 38887838 38087928 37888020 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Sat Aug 31 2024 Valid 312000Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms capable of producing mainly damaging winds remain possible this afternoon and evening from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts may also occur across parts of the northern Great Lakes. ...20Z Update... Some minor adjustments have been made to the Marginal and Slight Risks based on observational trends, but no major changes have been made to the outlook. Scattered damaging winds remain possible through late afternoon and perhaps into early evening from parts of WV into western/central PA and western MD/VA. See MCD 2040 regarding the short-term threat in this area. Also, see the previous discussion below for more information. ..Dean.. 08/31/2024 .PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Aug 31 2024/ ...Mid-Atlantic into the Ohio and Tennessee Valleys... A mid/upper-level trough will move eastward across Ontario/Quebec and the Great Lakes today while undergoing some amplification. Ahead of this feature, a surface front will move eastward over parts of the Northeast/Mid-Atlantic, and southeastward over the OH Valley before eventually stalling. A warm front will lift north through the period across the mid-Atlantic and northeast states. Late morning visible satellite imagery shows substantial low cloud cover over much of the Northeast and Mid-Atlantic. This will reduce daytime heating and delay destabilization, especially east of the Blue Ridge Mountains. However, with a moist low-level air mass in place, even modest diurnal heating will result in sufficient destabilization to support some risk for strong/severe storms. The stronger mid-level flow associated with the upper trough is expected to remain generally displaced to the north/west of the surface warm sector. Even so, modestly increasing west-southwesterly winds with height through mid levels should support around 20-30 kt of deep-layer shear across parts of the central Appalachians and upper OH Valley vicinity. This shear will be sufficient for loosely organized multicell clusters to develop or intensify and subsequently spread east-southeastward through this afternoon. Isolated to scattered damaging winds should be the main threat with this convection, although some hail may also occur with the strongest cells. Storms should gradually weaken with eastward extent by this evening across the Mid-Atlantic while encountering a less unstable air mass. Weaker deep-layer shear with southward extent into the lower OH Valley and TN Valley will likely limit overall thunderstorm organization. However, occasional damaging winds may still occur with thunderstorms along/south of the front as low-level lapse rates steepen. ...Northern Great Lakes... Strong west-northwesterly mid-level flow will exist over the Upper Midwest and northern Great Lakes in association with a shortwave trough embedded within a broader cyclonic flow. While low-level moisture and related instability are both expected to remain limited, large-scale ascent and strong deep-layer shear may support the development of low-topped thunderstorms this afternoon. If these thunderstorms can be sustained, then isolated strong to severe winds may occur given the forecast strength of the low to mid-level flow in the presence of steepened low-level lapse rates. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Sat Aug 31 2024 Valid 312000Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms capable of producing mainly damaging winds remain possible this afternoon and evening from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts may also occur across parts of the northern Great Lakes. ...20Z Update... Some minor adjustments have been made to the Marginal and Slight Risks based on observational trends, but no major changes have been made to the outlook. Scattered damaging winds remain possible through late afternoon and perhaps into early evening from parts of WV into western/central PA and western MD/VA. See MCD 2040 regarding the short-term threat in this area. Also, see the previous discussion below for more information. ..Dean.. 08/31/2024 .PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Aug 31 2024/ ...Mid-Atlantic into the Ohio and Tennessee Valleys... A mid/upper-level trough will move eastward across Ontario/Quebec and the Great Lakes today while undergoing some amplification. Ahead of this feature, a surface front will move eastward over parts of the Northeast/Mid-Atlantic, and southeastward over the OH Valley before eventually stalling. A warm front will lift north through the period across the mid-Atlantic and northeast states. Late morning visible satellite imagery shows substantial low cloud cover over much of the Northeast and Mid-Atlantic. This will reduce daytime heating and delay destabilization, especially east of the Blue Ridge Mountains. However, with a moist low-level air mass in place, even modest diurnal heating will result in sufficient destabilization to support some risk for strong/severe storms. The stronger mid-level flow associated with the upper trough is expected to remain generally displaced to the north/west of the surface warm sector. Even so, modestly increasing west-southwesterly winds with height through mid levels should support around 20-30 kt of deep-layer shear across parts of the central Appalachians and upper OH Valley vicinity. This shear will be sufficient for loosely organized multicell clusters to develop or intensify and subsequently spread east-southeastward through this afternoon. Isolated to scattered damaging winds should be the main threat with this convection, although some hail may also occur with the strongest cells. Storms should gradually weaken with eastward extent by this evening across the Mid-Atlantic while encountering a less unstable air mass. Weaker deep-layer shear with southward extent into the lower OH Valley and TN Valley will likely limit overall thunderstorm organization. However, occasional damaging winds may still occur with thunderstorms along/south of the front as low-level lapse rates steepen. ...Northern Great Lakes... Strong west-northwesterly mid-level flow will exist over the Upper Midwest and northern Great Lakes in association with a shortwave trough embedded within a broader cyclonic flow. While low-level moisture and related instability are both expected to remain limited, large-scale ascent and strong deep-layer shear may support the development of low-topped thunderstorms this afternoon. If these thunderstorms can be sustained, then isolated strong to severe winds may occur given the forecast strength of the low to mid-level flow in the presence of steepened low-level lapse rates. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Sat Aug 31 2024 Valid 312000Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms capable of producing mainly damaging winds remain possible this afternoon and evening from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts may also occur across parts of the northern Great Lakes. ...20Z Update... Some minor adjustments have been made to the Marginal and Slight Risks based on observational trends, but no major changes have been made to the outlook. Scattered damaging winds remain possible through late afternoon and perhaps into early evening from parts of WV into western/central PA and western MD/VA. See MCD 2040 regarding the short-term threat in this area. Also, see the previous discussion below for more information. ..Dean.. 08/31/2024 .PREV DISCUSSION... /ISSUED 1129 AM CDT Sat Aug 31 2024/ ...Mid-Atlantic into the Ohio and Tennessee Valleys... A mid/upper-level trough will move eastward across Ontario/Quebec and the Great Lakes today while undergoing some amplification. Ahead of this feature, a surface front will move eastward over parts of the Northeast/Mid-Atlantic, and southeastward over the OH Valley before eventually stalling. A warm front will lift north through the period across the mid-Atlantic and northeast states. Late morning visible satellite imagery shows substantial low cloud cover over much of the Northeast and Mid-Atlantic. This will reduce daytime heating and delay destabilization, especially east of the Blue Ridge Mountains. However, with a moist low-level air mass in place, even modest diurnal heating will result in sufficient destabilization to support some risk for strong/severe storms. The stronger mid-level flow associated with the upper trough is expected to remain generally displaced to the north/west of the surface warm sector. Even so, modestly increasing west-southwesterly winds with height through mid levels should support around 20-30 kt of deep-layer shear across parts of the central Appalachians and upper OH Valley vicinity. This shear will be sufficient for loosely organized multicell clusters to develop or intensify and subsequently spread east-southeastward through this afternoon. Isolated to scattered damaging winds should be the main threat with this convection, although some hail may also occur with the strongest cells. Storms should gradually weaken with eastward extent by this evening across the Mid-Atlantic while encountering a less unstable air mass. Weaker deep-layer shear with southward extent into the lower OH Valley and TN Valley will likely limit overall thunderstorm organization. However, occasional damaging winds may still occur with thunderstorms along/south of the front as low-level lapse rates steepen. ...Northern Great Lakes... Strong west-northwesterly mid-level flow will exist over the Upper Midwest and northern Great Lakes in association with a shortwave trough embedded within a broader cyclonic flow. While low-level moisture and related instability are both expected to remain limited, large-scale ascent and strong deep-layer shear may support the development of low-topped thunderstorms this afternoon. If these thunderstorms can be sustained, then isolated strong to severe winds may occur given the forecast strength of the low to mid-level flow in the presence of steepened low-level lapse rates. Read more