Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Sep 04 2019 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHEAST/NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a couple tornadoes remain possible through about 8 PM EDT across parts of the Mid-Atlantic States and New England. A few tornadoes may occur along the coast of South Carolina, mainly tonight through early Thursday morning. ...Discussion... Latest forecast areas, and reasoning, appear to remain valid for this outlook update. Aside from tweaks of the probability areas over the Northeast, to account for progression of ongoing convection, no substantive changes to the outlook appear necessary at this time. ..Goss.. 09/04/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Wed Sep 04 2019/ ...Mid-Atlantic/Northeast States and New England... At least isolated severe thunderstorms are expected across the region this afternoon into early/mid-evening. A shortwave trough centered over Lake Ontario at midday will steadily progress eastward toward northern New England by early evening. An attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with the trailing portion extending southwest across the central Appalachians through peak heating. Ahead of the cold front, mid 60s F surface dew points are prevalent from Connecticut/Rhode Island southwest into the Mid-Atlantic States where low 70s F are more common. As a plume of steeper mid-level lapse rates sampled by the 12Z Pittsburgh sounding spreads east, MLCAPE of 750-1500 J/kg should develop amid pockets of greater insolation in the lee of the Appalachians. Consistent with upstream regional 12Z soundings, strengthening mid-level (700-500 mb) southwesterly winds will overspread the region, particularly from Pennsylvania/New Jersey northeastward, with more modest flow aloft to the southwest. As storms develop/mature, the setup will support some initial supercells, and otherwise, multiple clusters/line segments with embedded supercell structures, particularly from northeast Pennsylvania/northern New Jersey across southern New England. Damaging winds will be the most common risk given the strength of the low/mid-level winds, but isolated marginally severe hail could also occur. There is also the potential for a couple of tornadoes, mainly across interior southeast New York and much of southern New England where the greatest combination of moderate low-level SRH and buoyancy are expected. The severe risk should gradually wane/move offshore by the mid-evening hours. ...Coastal Georgia/Carolinas... Hurricane Dorian will continue slowly north off the Florida/Georgia coast and approach coastal South Carolina by 12Z Thursday; reference NHC for the latest forecast details. The overall tornado threat is expected to remain limited along the Georgia/South Carolina coast through the afternoon. A greater potential for a few tornadoes should develop this evening into the overnight across coastal South Carolina as low-level northeasterly winds substantially strengthen and hodographs enlarge within the favored northeast quadrant of Dorian. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of South Carolina into far southern North Carolina. ...Deep South TX... TC Fernand will continue west across far northeast Mexico per latest NHC forecasts. Moderate low-level easterly flow will support adequate SRH for perhaps a brief tornado and/or isolated thunderstorm wind damage with scattered convection that persists from the northwest Gulf across Deep South Texas. This flow should gradually subside during the evening, limiting the severe storm risk tonight onward. ...North Dakota/northern Minnesota... A low-amplitude shortwave trough near the BC/AB/MT border will move east along the international border towards the Lake of the Woods region by 12Z Thursday. 700-mb warm advection will strengthen across northeast North Dakota into northwest Minnesota tonight. A cluster of elevated storms may evolve southeast from southeast SK/southwest MB overnight. Thin buoyancy will be a limiting factor, but robust speed shear within the cloud-bearing layer could support a few instances of marginally severe hail. ...Central High Plains... While particularly organized/sustained severe storms are not currently expected, a very isolated severe storm or two cannot be ruled across the region late this afternoon and early evening near the surface boundary/lee trough across the region. Neither deep-layer shear/buoyancy will be strong, but adequate moisture coincident with steep lapse rates and 25-30 kt effective shear could support some stronger updrafts/downdrafts capable of marginally severe hail and/or wind gusts. Any such risk appears most probable across northeast Colorado into southeast Wyoming and the southern Nebraska Panhandle. ...Arizona/Lower Colorado River Valley... Thunderstorm coverage may remain limited across the lower elevations of Arizona where a relatively greater reservoir of moisture/buoyancy will exist (particularly southwest Arizona). However, if/where storms develop later today, modest easterly steering flow and the hot/well-mixed nature of the boundary layer could conditionally support some stronger wind gusts, although the overall organized severe potential currently appears low. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0241 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z An ISODRYT area was added to portions of northern California into much of Oregon. Early in the period, elevated thunderstorms are possible in the Oregon Cascades vicinity. Weak buoyancy and relatively dry low levels should keep precipitation with this activity to a minimum. During the afternoon, more robust thunderstorm development is likely along the Oregon Cascades into central Oregon. Given the deep-layer shear expected, storms will be organized and likely produce substantial lightning. PWAT values near 1 inch along with scattered storm coverage suggests a swift transition to wetting rainfall is possible. However, given the potential lightning density and dry fuels, lightning ignitions will remain a concern on an isolated basis. Lightning activity may reach as far north as far southern Washington later in the period, but confidence is too low to highlight this area. Finally, more isolated and potentially drier storms are possible within the higher terrain of northern California (Klamath/Cascade Mountain vicinity). ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will remain fortified across the western CONUS, with a pronounced mid-level shortwave trough traversing the northern California/Pacific Northwest vicinity on Day 2/Thursday. Deep-layer ascent associated with the aforementioned trough will promote isolated to potentially scattered thunderstorm development throughout much of the afternoon and evening hours, with a couple of storms producing dry strikes. ...Northern California into the Pacific Northwest and northwestern Great Basin... Isolated to potentially scattered thunderstorm development is expected by mid-afternoon, as the aforementioned shortwave trough impinges on the area. While copious lightning may accompany the longer-lived, more organized storms, precipitable water values approaching 1 inch and clustering/training of stronger storm cores suggests that wetting rainfall may be abundant, despite faster storm motions and high cloud bases. An isolated dry thunderstorm delineation was withheld at this time given the amount of wetting rains possible. Nonetheless, at least a few dry strikes may occur, with potential fire starts aggravated by erratic gusty winds associated with the stronger storms. Please see the Day 2 Convective Outlook for more information regarding the severe wind threat. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0241 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z An ISODRYT area was added to portions of northern California into much of Oregon. Early in the period, elevated thunderstorms are possible in the Oregon Cascades vicinity. Weak buoyancy and relatively dry low levels should keep precipitation with this activity to a minimum. During the afternoon, more robust thunderstorm development is likely along the Oregon Cascades into central Oregon. Given the deep-layer shear expected, storms will be organized and likely produce substantial lightning. PWAT values near 1 inch along with scattered storm coverage suggests a swift transition to wetting rainfall is possible. However, given the potential lightning density and dry fuels, lightning ignitions will remain a concern on an isolated basis. Lightning activity may reach as far north as far southern Washington later in the period, but confidence is too low to highlight this area. Finally, more isolated and potentially drier storms are possible within the higher terrain of northern California (Klamath/Cascade Mountain vicinity). ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will remain fortified across the western CONUS, with a pronounced mid-level shortwave trough traversing the northern California/Pacific Northwest vicinity on Day 2/Thursday. Deep-layer ascent associated with the aforementioned trough will promote isolated to potentially scattered thunderstorm development throughout much of the afternoon and evening hours, with a couple of storms producing dry strikes. ...Northern California into the Pacific Northwest and northwestern Great Basin... Isolated to potentially scattered thunderstorm development is expected by mid-afternoon, as the aforementioned shortwave trough impinges on the area. While copious lightning may accompany the longer-lived, more organized storms, precipitable water values approaching 1 inch and clustering/training of stronger storm cores suggests that wetting rainfall may be abundant, despite faster storm motions and high cloud bases. An isolated dry thunderstorm delineation was withheld at this time given the amount of wetting rains possible. Nonetheless, at least a few dry strikes may occur, with potential fire starts aggravated by erratic gusty winds associated with the stronger storms. Please see the Day 2 Convective Outlook for more information regarding the severe wind threat. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0241 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z An ISODRYT area was added to portions of northern California into much of Oregon. Early in the period, elevated thunderstorms are possible in the Oregon Cascades vicinity. Weak buoyancy and relatively dry low levels should keep precipitation with this activity to a minimum. During the afternoon, more robust thunderstorm development is likely along the Oregon Cascades into central Oregon. Given the deep-layer shear expected, storms will be organized and likely produce substantial lightning. PWAT values near 1 inch along with scattered storm coverage suggests a swift transition to wetting rainfall is possible. However, given the potential lightning density and dry fuels, lightning ignitions will remain a concern on an isolated basis. Lightning activity may reach as far north as far southern Washington later in the period, but confidence is too low to highlight this area. Finally, more isolated and potentially drier storms are possible within the higher terrain of northern California (Klamath/Cascade Mountain vicinity). ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will remain fortified across the western CONUS, with a pronounced mid-level shortwave trough traversing the northern California/Pacific Northwest vicinity on Day 2/Thursday. Deep-layer ascent associated with the aforementioned trough will promote isolated to potentially scattered thunderstorm development throughout much of the afternoon and evening hours, with a couple of storms producing dry strikes. ...Northern California into the Pacific Northwest and northwestern Great Basin... Isolated to potentially scattered thunderstorm development is expected by mid-afternoon, as the aforementioned shortwave trough impinges on the area. While copious lightning may accompany the longer-lived, more organized storms, precipitable water values approaching 1 inch and clustering/training of stronger storm cores suggests that wetting rainfall may be abundant, despite faster storm motions and high cloud bases. An isolated dry thunderstorm delineation was withheld at this time given the amount of wetting rains possible. Nonetheless, at least a few dry strikes may occur, with potential fire starts aggravated by erratic gusty winds associated with the stronger storms. Please see the Day 2 Convective Outlook for more information regarding the severe wind threat. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0241 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z An ISODRYT area was added to portions of northern California into much of Oregon. Early in the period, elevated thunderstorms are possible in the Oregon Cascades vicinity. Weak buoyancy and relatively dry low levels should keep precipitation with this activity to a minimum. During the afternoon, more robust thunderstorm development is likely along the Oregon Cascades into central Oregon. Given the deep-layer shear expected, storms will be organized and likely produce substantial lightning. PWAT values near 1 inch along with scattered storm coverage suggests a swift transition to wetting rainfall is possible. However, given the potential lightning density and dry fuels, lightning ignitions will remain a concern on an isolated basis. Lightning activity may reach as far north as far southern Washington later in the period, but confidence is too low to highlight this area. Finally, more isolated and potentially drier storms are possible within the higher terrain of northern California (Klamath/Cascade Mountain vicinity). ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0138 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will remain fortified across the western CONUS, with a pronounced mid-level shortwave trough traversing the northern California/Pacific Northwest vicinity on Day 2/Thursday. Deep-layer ascent associated with the aforementioned trough will promote isolated to potentially scattered thunderstorm development throughout much of the afternoon and evening hours, with a couple of storms producing dry strikes. ...Northern California into the Pacific Northwest and northwestern Great Basin... Isolated to potentially scattered thunderstorm development is expected by mid-afternoon, as the aforementioned shortwave trough impinges on the area. While copious lightning may accompany the longer-lived, more organized storms, precipitable water values approaching 1 inch and clustering/training of stronger storm cores suggests that wetting rainfall may be abundant, despite faster storm motions and high cloud bases. An isolated dry thunderstorm delineation was withheld at this time given the amount of wetting rains possible. Nonetheless, at least a few dry strikes may occur, with potential fire starts aggravated by erratic gusty winds associated with the stronger storms. Please see the Day 2 Convective Outlook for more information regarding the severe wind threat. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0634 Status Updates
000-042040- STATUS REPORT ON WW 634 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 SW AVP TO 30 WSW PSF TO 25 WSW MWN. ..MOSIER..09/04/19 ATTN...WFO...OKX...BOX...ALY...GYX...PHI...BGM...BTV... STATUS REPORT FOR WS 634 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC001-003-005-007-009-011-013-015-042040- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD HARTFORD LITCHFIELD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MEC005-031-042040- ME . MAINE COUNTIES INCLUDED ARE CUMBERLAND YORK MAC003-009-011-013-015-017-027-042040- MA . MASSACHUSETTS COUNTIES INCLUDED ARE BERKSHIRE ESSEX FRANKLIN Read more

MD 1925 CONCERNING SEVERE THUNDERSTORM WATCH 634... FOR SOUTHEAST NY...SOUTHERN VT/NH...FAR SOUTHWEST ME...CT...MA...RI...NORTHERN NJ...FAR NORTHEAST PA
Mesoscale Discussion 1925 NWS Storm Prediction Center Norman OK 0227 PM CDT Wed Sep 04 2019 Areas affected...Southeast NY...Southern VT/NH...Far southwest ME...CT...MA...RI...Northern NJ...Far Northeast PA Concerning...Severe Thunderstorm Watch 634... Valid 041927Z - 042100Z The severe weather threat for Severe Thunderstorm Watch 634 continues. SUMMARY...Threat for damaging wind gusts continues across much of Severe Thunderstorm Watch 634. DISCUSSION...Cold front continues to progress eastward across the Northeast and recent surface analysis places the boundary from north-central VT southwestward to just east of ALB to CXY (in southeast PA). Northern portion of the line of thunderstorms initially along the front has accelerated slightly ahead of it while also losing intensity. This loss of intensity is likely tied reduced lift away from the front and less buoyancy from lower surface temperatures. Warm layer noted around 500-600 mb on the 18Z ALB sounding could also be contributing to reduced updraft strength. Southern portion of this line of has maintained its intensity and is moving into a slightly more favorable thermodynamic environment. Expectation is for this portion of the line to continue eastward, posing a risk for damaging wind gusts. Additional development is also possible farther south along the front across far northeast PA and northern NJ. These storms will also pose a risk for damaging wind gusts. A low tornado threat remains, but surface winds have been veering westerly well ahead of the front, further reducing any tornado potential. ..Mosier.. 09/04/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM... LAT...LON 43647336 44017283 44137254 44257206 44267170 44207084 43937027 43587013 41967109 40577250 40367450 40817570 42497403 43647336 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE EASTERN NORTH CAROLINA VICINITY... ...SUMMARY... Isolated tornadoes will be possible Thursday in association with Hurricane Dorian from northern coastal South Carolina through coastal North Carolina. Isolated downburst winds will be possible over a portion of western and central Oregon Thursday afternoon. ...Synopsis... Fast flow aloft will remain confined to the northern tier of the U.S. Thursday, as a large ridge prevails across much of the U.S. A short-wave trough over the eastern Pacific will move into the Pacific Northwest with time, weakening and being shunted northeastward as it impinges on the ridge. Meanwhile, Hurricane Dorian is progged to move northeastward with time, in the vicinity of the Carolina coast. Aside from Dorian, the surface pattern across the U.S. will remain largely nondescript, though a weak low/front is progged to shift southeast across the Upper Midwest vicinity through the period. ...Eastern Carolinas... Hurricane Dorian is progged to move northeast from just off the southern South Carolina coast at the start of the period, to the North Carolina outer banks area late in the period, per the lastest forecast from the National Hurricane Center (NHC). As the storm advances, and the favored northeast quadrant of the storm begins to increasingly affect the coastal Carolinas, increasingly large low-level hodographs will evolve -- particularly across eastern North Carolina. With very moist onshore flow contributing to modest CAPE, embedded supercells moving onshore will be capable of producing isolated tornadoes, particularly through the second half of the period. ...Western and central Oregon... Steep mid-level lapse rates will spread across Oregon downstream of a shortwave trough moving inland with time, from the eastern Pacific. With a dry boundary layer expected, diurnal heating/mixing will yield a deep/dry sub-cloud layer, but with modest CAPE above the LFC. Increasing ascent ahead of the shortwave trough will support at least isolated high-based storms developing later during the afternoon and evening. With shear increasing as the trough approaches, a few storms may organize/ develop mid-level rotation, with isolated damaging wind gusts and perhaps marginal hail possible with a few stronger storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/04/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE EASTERN NORTH CAROLINA VICINITY... ...SUMMARY... Isolated tornadoes will be possible Thursday in association with Hurricane Dorian from northern coastal South Carolina through coastal North Carolina. Isolated downburst winds will be possible over a portion of western and central Oregon Thursday afternoon. ...Synopsis... Fast flow aloft will remain confined to the northern tier of the U.S. Thursday, as a large ridge prevails across much of the U.S. A short-wave trough over the eastern Pacific will move into the Pacific Northwest with time, weakening and being shunted northeastward as it impinges on the ridge. Meanwhile, Hurricane Dorian is progged to move northeastward with time, in the vicinity of the Carolina coast. Aside from Dorian, the surface pattern across the U.S. will remain largely nondescript, though a weak low/front is progged to shift southeast across the Upper Midwest vicinity through the period. ...Eastern Carolinas... Hurricane Dorian is progged to move northeast from just off the southern South Carolina coast at the start of the period, to the North Carolina outer banks area late in the period, per the lastest forecast from the National Hurricane Center (NHC). As the storm advances, and the favored northeast quadrant of the storm begins to increasingly affect the coastal Carolinas, increasingly large low-level hodographs will evolve -- particularly across eastern North Carolina. With very moist onshore flow contributing to modest CAPE, embedded supercells moving onshore will be capable of producing isolated tornadoes, particularly through the second half of the period. ...Western and central Oregon... Steep mid-level lapse rates will spread across Oregon downstream of a shortwave trough moving inland with time, from the eastern Pacific. With a dry boundary layer expected, diurnal heating/mixing will yield a deep/dry sub-cloud layer, but with modest CAPE above the LFC. Increasing ascent ahead of the shortwave trough will support at least isolated high-based storms developing later during the afternoon and evening. With shear increasing as the trough approaches, a few storms may organize/ develop mid-level rotation, with isolated damaging wind gusts and perhaps marginal hail possible with a few stronger storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/04/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE EASTERN NORTH CAROLINA VICINITY... ...SUMMARY... Isolated tornadoes will be possible Thursday in association with Hurricane Dorian from northern coastal South Carolina through coastal North Carolina. Isolated downburst winds will be possible over a portion of western and central Oregon Thursday afternoon. ...Synopsis... Fast flow aloft will remain confined to the northern tier of the U.S. Thursday, as a large ridge prevails across much of the U.S. A short-wave trough over the eastern Pacific will move into the Pacific Northwest with time, weakening and being shunted northeastward as it impinges on the ridge. Meanwhile, Hurricane Dorian is progged to move northeastward with time, in the vicinity of the Carolina coast. Aside from Dorian, the surface pattern across the U.S. will remain largely nondescript, though a weak low/front is progged to shift southeast across the Upper Midwest vicinity through the period. ...Eastern Carolinas... Hurricane Dorian is progged to move northeast from just off the southern South Carolina coast at the start of the period, to the North Carolina outer banks area late in the period, per the lastest forecast from the National Hurricane Center (NHC). As the storm advances, and the favored northeast quadrant of the storm begins to increasingly affect the coastal Carolinas, increasingly large low-level hodographs will evolve -- particularly across eastern North Carolina. With very moist onshore flow contributing to modest CAPE, embedded supercells moving onshore will be capable of producing isolated tornadoes, particularly through the second half of the period. ...Western and central Oregon... Steep mid-level lapse rates will spread across Oregon downstream of a shortwave trough moving inland with time, from the eastern Pacific. With a dry boundary layer expected, diurnal heating/mixing will yield a deep/dry sub-cloud layer, but with modest CAPE above the LFC. Increasing ascent ahead of the shortwave trough will support at least isolated high-based storms developing later during the afternoon and evening. With shear increasing as the trough approaches, a few storms may organize/ develop mid-level rotation, with isolated damaging wind gusts and perhaps marginal hail possible with a few stronger storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/04/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE EASTERN NORTH CAROLINA VICINITY... ...SUMMARY... Isolated tornadoes will be possible Thursday in association with Hurricane Dorian from northern coastal South Carolina through coastal North Carolina. Isolated downburst winds will be possible over a portion of western and central Oregon Thursday afternoon. ...Synopsis... Fast flow aloft will remain confined to the northern tier of the U.S. Thursday, as a large ridge prevails across much of the U.S. A short-wave trough over the eastern Pacific will move into the Pacific Northwest with time, weakening and being shunted northeastward as it impinges on the ridge. Meanwhile, Hurricane Dorian is progged to move northeastward with time, in the vicinity of the Carolina coast. Aside from Dorian, the surface pattern across the U.S. will remain largely nondescript, though a weak low/front is progged to shift southeast across the Upper Midwest vicinity through the period. ...Eastern Carolinas... Hurricane Dorian is progged to move northeast from just off the southern South Carolina coast at the start of the period, to the North Carolina outer banks area late in the period, per the lastest forecast from the National Hurricane Center (NHC). As the storm advances, and the favored northeast quadrant of the storm begins to increasingly affect the coastal Carolinas, increasingly large low-level hodographs will evolve -- particularly across eastern North Carolina. With very moist onshore flow contributing to modest CAPE, embedded supercells moving onshore will be capable of producing isolated tornadoes, particularly through the second half of the period. ...Western and central Oregon... Steep mid-level lapse rates will spread across Oregon downstream of a shortwave trough moving inland with time, from the eastern Pacific. With a dry boundary layer expected, diurnal heating/mixing will yield a deep/dry sub-cloud layer, but with modest CAPE above the LFC. Increasing ascent ahead of the shortwave trough will support at least isolated high-based storms developing later during the afternoon and evening. With shear increasing as the trough approaches, a few storms may organize/ develop mid-level rotation, with isolated damaging wind gusts and perhaps marginal hail possible with a few stronger storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 5% - Marginal Hail: 5% - Marginal ..Goss.. 09/04/2019 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1201 PM CDT Wed Sep 04 2019 Valid 041700Z - 051200Z Modifications have been made to the ISODRYT area. Confidence in a broader area of dry lighting concerns has decreased across Nevada. PWAT values will be higher than yesterday, particularly in central/southern Nevada. The exception will be in northeast Nevada where enough dry fuels remain and PWAT should trend closer to 0.75-0.8 inches. Concern for dry lightning strikes in northern California and portions of western Oregon has increased. Elevated buoyancy is forecast this evening and overnight with ascent increasing from an approaching shortwave trough. These elevated storms are not expected to produce significant rainfall and should be moving relatively quickly. The northward extent of this activity is somewhat uncertain, though the possibility for efficient lightning ignitions is enough to include the area. The elevated are across northern Montana remains unchanged. Locally elevated to briefly critical conditions are possible into south-central Montana. Farther south in Wyoming, away from the stronger mid-level flow, locally elevated may still occur, but confidence is less than points north. ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0110 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will hold firm across the western CONUS. Nonetheless, a mid-level shortwave trough embedded in the larger scale flow will crest the ridge and traverse the northern Rockies, encouraging a mass response for surface dry, breezy conditions, which may be favorable for some wildfire-spread. Also, a second mid-level impulse will impinge on the California coastline, promoting deep-layer ascent across northern portions of California into the western Great Basin, where at least isolated thunderstorm potential will exist. ...Northern and central Rockies... By peak afternoon heating, the surface isallobaric response to a glancing mid-level shortwave, combined with boundary layer mixing of the stronger flow aloft to the surface, will foster 15-20 mph sustained westerly surface winds and 15-25% RH. Finer fuels have sufficiently dried across the region to support at least modest wildfire-spread potential, with an elevated area remaining in place across parts of northern Montana. At least localized elevated conditions may also occur farther south to the Montana/Idaho border, but the patchy and brief nature of these conditions precludes a delineation across this area at this time. Widespread 10-15 mph westerly winds and critically low RH are expected across portions of central into eastern Wyoming during the afternoon as well. While fuels have recently become receptive to fire spread across portions of this area, model guidance struggles to show more widespread winds exceeding 15 mph, hence no elevated delineation at this time, though trends will continue to be monitored for a possible elevated area addition in the next forecast update. ...Northern California into the western Great Basin... Storms are first expected to initiate mainly across northern Nevada by afternoon peak heating. Later, storms are expected to initiate across northern California during the evening/overnight hours. Modest storm motions and wetting rainfall may be the biggest inhibiting factors to a more robust lightning-induced fire threat. Nonetheless, precipitable water values in the 0.50-0.75 inch range will foster at least isolated dry strikes on the peripheral of updrafts atop near-critical to critically dry fuels. As such, maintaining an isolated dry thunderstorm delineation across northern California into the western Great Basin appears warranted. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1201 PM CDT Wed Sep 04 2019 Valid 041700Z - 051200Z Modifications have been made to the ISODRYT area. Confidence in a broader area of dry lighting concerns has decreased across Nevada. PWAT values will be higher than yesterday, particularly in central/southern Nevada. The exception will be in northeast Nevada where enough dry fuels remain and PWAT should trend closer to 0.75-0.8 inches. Concern for dry lightning strikes in northern California and portions of western Oregon has increased. Elevated buoyancy is forecast this evening and overnight with ascent increasing from an approaching shortwave trough. These elevated storms are not expected to produce significant rainfall and should be moving relatively quickly. The northward extent of this activity is somewhat uncertain, though the possibility for efficient lightning ignitions is enough to include the area. The elevated are across northern Montana remains unchanged. Locally elevated to briefly critical conditions are possible into south-central Montana. Farther south in Wyoming, away from the stronger mid-level flow, locally elevated may still occur, but confidence is less than points north. ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0110 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will hold firm across the western CONUS. Nonetheless, a mid-level shortwave trough embedded in the larger scale flow will crest the ridge and traverse the northern Rockies, encouraging a mass response for surface dry, breezy conditions, which may be favorable for some wildfire-spread. Also, a second mid-level impulse will impinge on the California coastline, promoting deep-layer ascent across northern portions of California into the western Great Basin, where at least isolated thunderstorm potential will exist. ...Northern and central Rockies... By peak afternoon heating, the surface isallobaric response to a glancing mid-level shortwave, combined with boundary layer mixing of the stronger flow aloft to the surface, will foster 15-20 mph sustained westerly surface winds and 15-25% RH. Finer fuels have sufficiently dried across the region to support at least modest wildfire-spread potential, with an elevated area remaining in place across parts of northern Montana. At least localized elevated conditions may also occur farther south to the Montana/Idaho border, but the patchy and brief nature of these conditions precludes a delineation across this area at this time. Widespread 10-15 mph westerly winds and critically low RH are expected across portions of central into eastern Wyoming during the afternoon as well. While fuels have recently become receptive to fire spread across portions of this area, model guidance struggles to show more widespread winds exceeding 15 mph, hence no elevated delineation at this time, though trends will continue to be monitored for a possible elevated area addition in the next forecast update. ...Northern California into the western Great Basin... Storms are first expected to initiate mainly across northern Nevada by afternoon peak heating. Later, storms are expected to initiate across northern California during the evening/overnight hours. Modest storm motions and wetting rainfall may be the biggest inhibiting factors to a more robust lightning-induced fire threat. Nonetheless, precipitable water values in the 0.50-0.75 inch range will foster at least isolated dry strikes on the peripheral of updrafts atop near-critical to critically dry fuels. As such, maintaining an isolated dry thunderstorm delineation across northern California into the western Great Basin appears warranted. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1201 PM CDT Wed Sep 04 2019 Valid 041700Z - 051200Z Modifications have been made to the ISODRYT area. Confidence in a broader area of dry lighting concerns has decreased across Nevada. PWAT values will be higher than yesterday, particularly in central/southern Nevada. The exception will be in northeast Nevada where enough dry fuels remain and PWAT should trend closer to 0.75-0.8 inches. Concern for dry lightning strikes in northern California and portions of western Oregon has increased. Elevated buoyancy is forecast this evening and overnight with ascent increasing from an approaching shortwave trough. These elevated storms are not expected to produce significant rainfall and should be moving relatively quickly. The northward extent of this activity is somewhat uncertain, though the possibility for efficient lightning ignitions is enough to include the area. The elevated are across northern Montana remains unchanged. Locally elevated to briefly critical conditions are possible into south-central Montana. Farther south in Wyoming, away from the stronger mid-level flow, locally elevated may still occur, but confidence is less than points north. ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0110 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will hold firm across the western CONUS. Nonetheless, a mid-level shortwave trough embedded in the larger scale flow will crest the ridge and traverse the northern Rockies, encouraging a mass response for surface dry, breezy conditions, which may be favorable for some wildfire-spread. Also, a second mid-level impulse will impinge on the California coastline, promoting deep-layer ascent across northern portions of California into the western Great Basin, where at least isolated thunderstorm potential will exist. ...Northern and central Rockies... By peak afternoon heating, the surface isallobaric response to a glancing mid-level shortwave, combined with boundary layer mixing of the stronger flow aloft to the surface, will foster 15-20 mph sustained westerly surface winds and 15-25% RH. Finer fuels have sufficiently dried across the region to support at least modest wildfire-spread potential, with an elevated area remaining in place across parts of northern Montana. At least localized elevated conditions may also occur farther south to the Montana/Idaho border, but the patchy and brief nature of these conditions precludes a delineation across this area at this time. Widespread 10-15 mph westerly winds and critically low RH are expected across portions of central into eastern Wyoming during the afternoon as well. While fuels have recently become receptive to fire spread across portions of this area, model guidance struggles to show more widespread winds exceeding 15 mph, hence no elevated delineation at this time, though trends will continue to be monitored for a possible elevated area addition in the next forecast update. ...Northern California into the western Great Basin... Storms are first expected to initiate mainly across northern Nevada by afternoon peak heating. Later, storms are expected to initiate across northern California during the evening/overnight hours. Modest storm motions and wetting rainfall may be the biggest inhibiting factors to a more robust lightning-induced fire threat. Nonetheless, precipitable water values in the 0.50-0.75 inch range will foster at least isolated dry strikes on the peripheral of updrafts atop near-critical to critically dry fuels. As such, maintaining an isolated dry thunderstorm delineation across northern California into the western Great Basin appears warranted. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1201 PM CDT Wed Sep 04 2019 Valid 041700Z - 051200Z Modifications have been made to the ISODRYT area. Confidence in a broader area of dry lighting concerns has decreased across Nevada. PWAT values will be higher than yesterday, particularly in central/southern Nevada. The exception will be in northeast Nevada where enough dry fuels remain and PWAT should trend closer to 0.75-0.8 inches. Concern for dry lightning strikes in northern California and portions of western Oregon has increased. Elevated buoyancy is forecast this evening and overnight with ascent increasing from an approaching shortwave trough. These elevated storms are not expected to produce significant rainfall and should be moving relatively quickly. The northward extent of this activity is somewhat uncertain, though the possibility for efficient lightning ignitions is enough to include the area. The elevated are across northern Montana remains unchanged. Locally elevated to briefly critical conditions are possible into south-central Montana. Farther south in Wyoming, away from the stronger mid-level flow, locally elevated may still occur, but confidence is less than points north. ..Wendt.. 09/04/2019 .PREV DISCUSSION... /ISSUED 0110 AM CDT Wed Sep 04 2019/ ...Synopsis... A mid-level ridge will hold firm across the western CONUS. Nonetheless, a mid-level shortwave trough embedded in the larger scale flow will crest the ridge and traverse the northern Rockies, encouraging a mass response for surface dry, breezy conditions, which may be favorable for some wildfire-spread. Also, a second mid-level impulse will impinge on the California coastline, promoting deep-layer ascent across northern portions of California into the western Great Basin, where at least isolated thunderstorm potential will exist. ...Northern and central Rockies... By peak afternoon heating, the surface isallobaric response to a glancing mid-level shortwave, combined with boundary layer mixing of the stronger flow aloft to the surface, will foster 15-20 mph sustained westerly surface winds and 15-25% RH. Finer fuels have sufficiently dried across the region to support at least modest wildfire-spread potential, with an elevated area remaining in place across parts of northern Montana. At least localized elevated conditions may also occur farther south to the Montana/Idaho border, but the patchy and brief nature of these conditions precludes a delineation across this area at this time. Widespread 10-15 mph westerly winds and critically low RH are expected across portions of central into eastern Wyoming during the afternoon as well. While fuels have recently become receptive to fire spread across portions of this area, model guidance struggles to show more widespread winds exceeding 15 mph, hence no elevated delineation at this time, though trends will continue to be monitored for a possible elevated area addition in the next forecast update. ...Northern California into the western Great Basin... Storms are first expected to initiate mainly across northern Nevada by afternoon peak heating. Later, storms are expected to initiate across northern California during the evening/overnight hours. Modest storm motions and wetting rainfall may be the biggest inhibiting factors to a more robust lightning-induced fire threat. Nonetheless, precipitable water values in the 0.50-0.75 inch range will foster at least isolated dry strikes on the peripheral of updrafts atop near-critical to critically dry fuels. As such, maintaining an isolated dry thunderstorm delineation across northern California into the western Great Basin appears warranted. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0634 Status Updates
STATUS FOR WATCH 0634 HAS NOT BEEN ISSUED YET Read more

WW 0634 Status Updates
STATUS FOR WATCH 0634 HAS NOT BEEN ISSUED YET Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2019 Valid 041630Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST STATES AND COASTAL SOUTH CAROLINA... ...SUMMARY... Scattered damaging winds and a couple tornadoes are possible through about 8 PM EDT across parts of the Mid-Atlantic States and New England. A few tornadoes may occur along the coast of South Carolina, mainly tonight through early Thursday morning. ...Mid-Atlantic/Northeast States and New England... At least isolated severe thunderstorms are expected across the region this afternoon into early/mid-evening. A shortwave trough centered over Lake Ontario at midday will steadily progress eastward toward northern New England by early evening. An attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with the trailing portion extending southwest across the central Appalachians through peak heating. Ahead of the cold front, mid 60s F surface dew points are prevalent from Connecticut/Rhode Island southwest into the Mid-Atlantic States where low 70s F are more common. As a plume of steeper mid-level lapse rates sampled by the 12Z Pittsburgh sounding spreads east, MLCAPE of 750-1500 J/kg should develop amid pockets of greater insolation in the lee of the Appalachians. Consistent with upstream regional 12Z soundings, strengthening mid-level (700-500 mb) southwesterly winds will overspread the region, particularly from Pennsylvania/New Jersey northeastward, with more modest flow aloft to the southwest. As storms develop/mature, the setup will support some initial supercells, and otherwise, multiple clusters/line segments with embedded supercell structures, particularly from northeast Pennsylvania/northern New Jersey across southern New England. Damaging winds will be the most common risk given the strength of the low/mid-level winds, but isolated marginally severe hail could also occur. There is also the potential for a couple of tornadoes, mainly across interior southeast New York and much of southern New England where the greatest combination of moderate low-level SRH and buoyancy are expected. The severe risk should gradually wane/move offshore by the mid-evening hours. ...Coastal Georgia/Carolinas... Hurricane Dorian will continue slowly north off the Florida/Georgia coast and approach coastal South Carolina by 12Z Thursday; reference NHC for the latest forecast details. The overall tornado threat is expected to remain limited along the Georgia/South Carolina coast through the afternoon. A greater potential for a few tornadoes should develop this evening into the overnight across coastal South Carolina as low-level northeasterly winds substantially strengthen and hodographs enlarge within the favored northeast quadrant of Dorian. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of South Carolina into far southern North Carolina. ...Deep South TX... TC Fernand will continue west across far northeast Mexico per latest NHC forecasts. Moderate low-level easterly flow will support adequate SRH for perhaps a brief tornado and/or isolated thunderstorm wind damage with scattered convection that persists from the northwest Gulf across Deep South Texas. This flow should gradually subside during the evening, limiting the severe storm risk tonight onward. ...North Dakota/northern Minnesota... A low-amplitude shortwave trough near the BC/AB/MT border will move east along the international border towards the Lake of the Woods region by 12Z Thursday. 700-mb warm advection will strengthen across northeast North Dakota into northwest Minnesota tonight. A cluster of elevated storms may evolve southeast from southeast SK/southwest MB overnight. Thin buoyancy will be a limiting factor, but robust speed shear within the cloud-bearing layer could support a few instances of marginally severe hail. ...Central High Plains... While particularly organized/sustained severe storms are not currently expected, a very isolated severe storm or two cannot be ruled across the region late this afternoon and early evening near the surface boundary/lee trough across the region. Neither deep-layer shear/buoyancy will be strong, but adequate moisture coincident with steep lapse rates and 25-30 kt effective shear could support some stronger updrafts/downdrafts capable of marginally severe hail and/or wind gusts. Any such risk appears most probable across northeast Colorado into southeast Wyoming and the southern Nebraska Panhandle. ...Arizona/Lower Colorado River Valley... Thunderstorm coverage may remain limited across the lower elevations of Arizona where a relatively greater reservoir of moisture/buoyancy will exist (particularly southwest Arizona). However, if/where storms develop later today, modest easterly steering flow and the hot/well-mixed nature of the boundary layer could conditionally support some stronger wind gusts, although the overall organized severe potential currently appears low. ..Guyer/Nauslar.. 09/04/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2019 Valid 041630Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST STATES AND COASTAL SOUTH CAROLINA... ...SUMMARY... Scattered damaging winds and a couple tornadoes are possible through about 8 PM EDT across parts of the Mid-Atlantic States and New England. A few tornadoes may occur along the coast of South Carolina, mainly tonight through early Thursday morning. ...Mid-Atlantic/Northeast States and New England... At least isolated severe thunderstorms are expected across the region this afternoon into early/mid-evening. A shortwave trough centered over Lake Ontario at midday will steadily progress eastward toward northern New England by early evening. An attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with the trailing portion extending southwest across the central Appalachians through peak heating. Ahead of the cold front, mid 60s F surface dew points are prevalent from Connecticut/Rhode Island southwest into the Mid-Atlantic States where low 70s F are more common. As a plume of steeper mid-level lapse rates sampled by the 12Z Pittsburgh sounding spreads east, MLCAPE of 750-1500 J/kg should develop amid pockets of greater insolation in the lee of the Appalachians. Consistent with upstream regional 12Z soundings, strengthening mid-level (700-500 mb) southwesterly winds will overspread the region, particularly from Pennsylvania/New Jersey northeastward, with more modest flow aloft to the southwest. As storms develop/mature, the setup will support some initial supercells, and otherwise, multiple clusters/line segments with embedded supercell structures, particularly from northeast Pennsylvania/northern New Jersey across southern New England. Damaging winds will be the most common risk given the strength of the low/mid-level winds, but isolated marginally severe hail could also occur. There is also the potential for a couple of tornadoes, mainly across interior southeast New York and much of southern New England where the greatest combination of moderate low-level SRH and buoyancy are expected. The severe risk should gradually wane/move offshore by the mid-evening hours. ...Coastal Georgia/Carolinas... Hurricane Dorian will continue slowly north off the Florida/Georgia coast and approach coastal South Carolina by 12Z Thursday; reference NHC for the latest forecast details. The overall tornado threat is expected to remain limited along the Georgia/South Carolina coast through the afternoon. A greater potential for a few tornadoes should develop this evening into the overnight across coastal South Carolina as low-level northeasterly winds substantially strengthen and hodographs enlarge within the favored northeast quadrant of Dorian. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of South Carolina into far southern North Carolina. ...Deep South TX... TC Fernand will continue west across far northeast Mexico per latest NHC forecasts. Moderate low-level easterly flow will support adequate SRH for perhaps a brief tornado and/or isolated thunderstorm wind damage with scattered convection that persists from the northwest Gulf across Deep South Texas. This flow should gradually subside during the evening, limiting the severe storm risk tonight onward. ...North Dakota/northern Minnesota... A low-amplitude shortwave trough near the BC/AB/MT border will move east along the international border towards the Lake of the Woods region by 12Z Thursday. 700-mb warm advection will strengthen across northeast North Dakota into northwest Minnesota tonight. A cluster of elevated storms may evolve southeast from southeast SK/southwest MB overnight. Thin buoyancy will be a limiting factor, but robust speed shear within the cloud-bearing layer could support a few instances of marginally severe hail. ...Central High Plains... While particularly organized/sustained severe storms are not currently expected, a very isolated severe storm or two cannot be ruled across the region late this afternoon and early evening near the surface boundary/lee trough across the region. Neither deep-layer shear/buoyancy will be strong, but adequate moisture coincident with steep lapse rates and 25-30 kt effective shear could support some stronger updrafts/downdrafts capable of marginally severe hail and/or wind gusts. Any such risk appears most probable across northeast Colorado into southeast Wyoming and the southern Nebraska Panhandle. ...Arizona/Lower Colorado River Valley... Thunderstorm coverage may remain limited across the lower elevations of Arizona where a relatively greater reservoir of moisture/buoyancy will exist (particularly southwest Arizona). However, if/where storms develop later today, modest easterly steering flow and the hot/well-mixed nature of the boundary layer could conditionally support some stronger wind gusts, although the overall organized severe potential currently appears low. ..Guyer/Nauslar.. 09/04/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2019 Valid 041630Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST STATES AND COASTAL SOUTH CAROLINA... ...SUMMARY... Scattered damaging winds and a couple tornadoes are possible through about 8 PM EDT across parts of the Mid-Atlantic States and New England. A few tornadoes may occur along the coast of South Carolina, mainly tonight through early Thursday morning. ...Mid-Atlantic/Northeast States and New England... At least isolated severe thunderstorms are expected across the region this afternoon into early/mid-evening. A shortwave trough centered over Lake Ontario at midday will steadily progress eastward toward northern New England by early evening. An attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with the trailing portion extending southwest across the central Appalachians through peak heating. Ahead of the cold front, mid 60s F surface dew points are prevalent from Connecticut/Rhode Island southwest into the Mid-Atlantic States where low 70s F are more common. As a plume of steeper mid-level lapse rates sampled by the 12Z Pittsburgh sounding spreads east, MLCAPE of 750-1500 J/kg should develop amid pockets of greater insolation in the lee of the Appalachians. Consistent with upstream regional 12Z soundings, strengthening mid-level (700-500 mb) southwesterly winds will overspread the region, particularly from Pennsylvania/New Jersey northeastward, with more modest flow aloft to the southwest. As storms develop/mature, the setup will support some initial supercells, and otherwise, multiple clusters/line segments with embedded supercell structures, particularly from northeast Pennsylvania/northern New Jersey across southern New England. Damaging winds will be the most common risk given the strength of the low/mid-level winds, but isolated marginally severe hail could also occur. There is also the potential for a couple of tornadoes, mainly across interior southeast New York and much of southern New England where the greatest combination of moderate low-level SRH and buoyancy are expected. The severe risk should gradually wane/move offshore by the mid-evening hours. ...Coastal Georgia/Carolinas... Hurricane Dorian will continue slowly north off the Florida/Georgia coast and approach coastal South Carolina by 12Z Thursday; reference NHC for the latest forecast details. The overall tornado threat is expected to remain limited along the Georgia/South Carolina coast through the afternoon. A greater potential for a few tornadoes should develop this evening into the overnight across coastal South Carolina as low-level northeasterly winds substantially strengthen and hodographs enlarge within the favored northeast quadrant of Dorian. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of South Carolina into far southern North Carolina. ...Deep South TX... TC Fernand will continue west across far northeast Mexico per latest NHC forecasts. Moderate low-level easterly flow will support adequate SRH for perhaps a brief tornado and/or isolated thunderstorm wind damage with scattered convection that persists from the northwest Gulf across Deep South Texas. This flow should gradually subside during the evening, limiting the severe storm risk tonight onward. ...North Dakota/northern Minnesota... A low-amplitude shortwave trough near the BC/AB/MT border will move east along the international border towards the Lake of the Woods region by 12Z Thursday. 700-mb warm advection will strengthen across northeast North Dakota into northwest Minnesota tonight. A cluster of elevated storms may evolve southeast from southeast SK/southwest MB overnight. Thin buoyancy will be a limiting factor, but robust speed shear within the cloud-bearing layer could support a few instances of marginally severe hail. ...Central High Plains... While particularly organized/sustained severe storms are not currently expected, a very isolated severe storm or two cannot be ruled across the region late this afternoon and early evening near the surface boundary/lee trough across the region. Neither deep-layer shear/buoyancy will be strong, but adequate moisture coincident with steep lapse rates and 25-30 kt effective shear could support some stronger updrafts/downdrafts capable of marginally severe hail and/or wind gusts. Any such risk appears most probable across northeast Colorado into southeast Wyoming and the southern Nebraska Panhandle. ...Arizona/Lower Colorado River Valley... Thunderstorm coverage may remain limited across the lower elevations of Arizona where a relatively greater reservoir of moisture/buoyancy will exist (particularly southwest Arizona). However, if/where storms develop later today, modest easterly steering flow and the hot/well-mixed nature of the boundary layer could conditionally support some stronger wind gusts, although the overall organized severe potential currently appears low. ..Guyer/Nauslar.. 09/04/2019 Read more