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WW 634 SEVERE TSTM CT MA ME NH NJ NY PA RI VT CW 041650Z - 050100Z
0-050100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 634 NWS Storm Prediction Center Norman OK 1250 PM EDT Wed Sep 4 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Massachusetts Southern Maine New Hampshire Northern New Jersey Southern and Eastern New York Eastern Pennsylvania Rhode Island Southern Vermont Coastal Waters * Effective this Wednesday afternoon and evening from 1250 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Multiple corridors of intensifying thunderstorm development are expected this afternoon along and ahead of a cold front. Adequate instability along with very strong deep-layer winds will yield the potential for storms capable of damaging winds and some hail. A tornado or two cannot be ruled out mainly across southeast New York into southern New England. The severe risk will diminish from west to east across the region by early/mid-evening. The severe thunderstorm watch area is approximately along and 100 statute miles east and west of a line from 30 miles north of Laconia NH to 35 miles east southeast of Allentown PA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 450. Mean storm motion vector 28030. ...Guyer Read more

Burned Area Emergency Response (BAER) teams have been established to begin burned area surveys of the wildfires that recently burned on federal lands of the U.S. Forest Service - Southwestern Region. BAER team surveys are rapid assessments of the burned areas that evaluate post-fire conditions of the burned watersheds and determine the potential for increased post-fire flooding, sediment flows, and rockslides. BAER teams typically consist of scientists and specialists including hydrologists, geologists, soil scientists, road engineers, botanists, wildlife and fisheries biologists, archaeologists, recreation and trails specialists, and geographic information specialists, from federal and state agencies. BAER teams work together during the burned area surveys, field data analysis and modeling phase, to present findings along with recommended BAER treatments to the Forest Supervisor. BAER teams analyze the data they collect during the surveys, to produce a “Soil Burn Severity”...

000
ABPZ20 KNHC 042319
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 PM PDT Wed Sep 4 2019

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

The National Hurricane Center is issuing advisories on Hurricane
Juliette, located several hundred miles west-southwest of the
southern tip of the Baja California peninsula.

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Cangialosi

Numerous oak trees in southeastern North Carolina were dying in a matter of weeks. Very young and very old oaks seem to be most affected. Extreme stressors, such as flooding from hurricanes, and recent drought were thought to be responsible. The North Carolina Forestry has received many calls from people in Pender, Brunswick, Bladen and Lenoir counties about their trees. Wilmington Morning Star (N.C.), Sept. 2, 2019

No Mesoscale Discussions are in effect as of Wed Sep 4 22:36:06 UTC 2019.

WW 0634 Status Updates
000-042340- STATUS REPORT ON WW 634 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NNW PHL TO 25 SSW POU TO 25 SSW ORH TO 30 NNW BOS TO 25 SE PSM. ..GLEASON..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 CTC001-007-009-011-013-015-042340- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MAC009-017-027-042340- MA . MASSACHUSETTS COUNTIES INCLUDED ARE ESSEX MIDDLESEX WORCESTER NJC003-013-017-019-021-023-025-027-031-035-039-042340- NJ . NEW JERSEY COUNTIES INCLUDED ARE BERGEN ESSEX HUDSON HUNTERDON MERCER MIDDLESEX Read more

WW 634 SEVERE TSTM CT MA ME NH NJ NY PA RI VT CW 041650Z - 050100Z
0-050100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 634 NWS Storm Prediction Center Norman OK 1250 PM EDT Wed Sep 4 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Massachusetts Southern Maine New Hampshire Northern New Jersey Southern and Eastern New York Eastern Pennsylvania Rhode Island Southern Vermont Coastal Waters * Effective this Wednesday afternoon and evening from 1250 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Multiple corridors of intensifying thunderstorm development are expected this afternoon along and ahead of a cold front. Adequate instability along with very strong deep-layer winds will yield the potential for storms capable of damaging winds and some hail. A tornado or two cannot be ruled out mainly across southeast New York into southern New England. The severe risk will diminish from west to east across the region by early/mid-evening. The severe thunderstorm watch area is approximately along and 100 statute miles east and west of a line from 30 miles north of Laconia NH to 35 miles east southeast of Allentown PA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 450. Mean storm motion vector 28030. ...Guyer Read more

Texas cattle producers in the West, Central and South regions were starting to supplement livestock as range conditions continued to deteriorate, due to heat and insufficient rain. SFN Today (Raleigh, N.C.), Aug. 30, 2019

While insect have played a role in in the wildfires that have burned Alaska forests this summer, heat and drought have had a larger impact. Alaska Public Media News (Anchorage, Alaska), Aug. 23, 2019

5-Day Uncertainty Track last updated Wed, 04 Sep 2019 20:39:41 GMT


Wind Speed Probabilities last updated Wed, 04 Sep 2019 20:39:41 GMT

WW 0634 Status Updates
000-042140- STATUS REPORT ON WW 634 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 SE IPT TO 10 WNW POU TO 15 ESE PSF TO 15 SE MWN. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1925 ..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 CTC001-003-005-007-009-011-013-015-042140- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD HARTFORD LITCHFIELD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MEC005-031-042140- ME . MAINE COUNTIES INCLUDED ARE CUMBERLAND YORK MAC009-011-013-015-017-027-042140- MA . MASSACHUSETTS COUNTIES INCLUDED ARE Read more

Issued at 200 PM PDT Wed Sep 04 2019 000 WTPZ41 KNHC 042038 TCDEP1 Hurricane Juliette Discussion Number 15 NWS National Hurricane Center Miami FL EP112019 200 PM PDT Wed Sep 04 2019 Juliette continues to exhibit a large, ragged eye in both visible and infrared satellite imagery, but there are some breaks in the convective banding. Warming of the cloud tops over the southeastern portion of the circulation has also been observed. Recent microwave data show that the low-level eye remains fairly well defined, and that the center was located a little south of the previous estimates. The initial intensity remains 85 kt, which is a blend of the various objective and subjective satellite intensity estimates. Although the vertical shear is forecast to remain quite low during the next several days, the hurricane will be moving over decreasing SSTs and into less favorable thermodynamic conditions. This should result in gradual weakening during the next several days, and Juliette is now forecast to become a remnant low by the end of the forecast period. The hurricane is moving west-northwestward or 295/6 kt. A mid-level ridge extending from the southwestern United States over the eastern Pacific should continue to steer Juliette west- northwestward at a slightly faster forward speed during the next 2 to 3 days. After that time, the cyclone is predicted to turn westward as it weakens and is steered by the easterly trade wind flow. The farther south initial position required a slight southward adjustment of the early portion of the track forecast, but the latter portion remains similar to the previous official forecast. The track guidance is tightly clustered and the NHC forecast is near middle of the envelope. The wind radii were adjusted slightly based on recent scatterometer data. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 19.4N 117.8W 85 KT 100 MPH 12H 05/0600Z 20.0N 118.9W 75 KT 85 MPH 24H 05/1800Z 21.1N 120.5W 70 KT 80 MPH 36H 06/0600Z 22.1N 122.4W 60 KT 70 MPH 48H 06/1800Z 23.0N 124.4W 50 KT 60 MPH 72H 07/1800Z 23.6N 128.1W 35 KT 40 MPH 96H 08/1800Z 23.2N 131.5W 30 KT 35 MPH 120H 09/1800Z 22.8N 135.5W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown

Issued at 2100 UTC WED SEP 04 2019 000 FOPZ11 KNHC 042038 PWSEP1 HURRICANE JULIETTE WIND SPEED PROBABILITIES NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL EP112019 2100 UTC WED SEP 04 2019 AT 2100Z THE CENTER OF HURRICANE JULIETTE WAS LOCATED NEAR LATITUDE 19.4 NORTH...LONGITUDE 117.8 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 85 KTS...100 MPH...155 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) PACIFIC DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 18Z WED AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 18Z WED 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN PERIODS TO TO TO TO TO TO TO 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN 18Z MON FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 20N 115W 34 2 2( 4) X( 4) X( 4) X( 4) X( 4) X( 4) 20N 120W 34 78 19(97) X(97) X(97) X(97) X(97) X(97) 20N 120W 50 7 40(47) 1(48) X(48) X(48) X(48) X(48) 20N 120W 64 1 17(18) X(18) X(18) X(18) X(18) X(18) 25N 120W 34 X 4( 4) 4( 8) 1( 9) X( 9) X( 9) X( 9) 20N 125W 34 X 3( 3) 3( 6) 4(10) 2(12) X(12) X(12) 25N 125W 34 X X( X) 4( 4) 10(14) 11(25) 1(26) X(26) 25N 125W 50 X X( X) X( X) 1( 1) 2( 3) X( 3) X( 3) 20N 130W 34 X X( X) X( X) X( X) 2( 2) 3( 5) X( 5) 25N 130W 34 X X( X) X( X) X( X) 7( 7) 6(13) 1(14) 20N 135W 34 X X( X) X( X) X( X) X( X) X( X) 4( 4) 25N 135W 34 X X( X) X( X) X( X) X( X) 1( 1) 4( 5) $$ FORECASTER BROWN

Issued at 200 PM PDT Wed Sep 04 2019 000 WTPZ31 KNHC 042038 TCPEP1 BULLETIN Hurricane Juliette Advisory Number 15 NWS National Hurricane Center Miami FL EP112019 200 PM PDT Wed Sep 04 2019 ...JULIETTE HEADING TOWARD COOLER WATERS... SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...19.4N 117.8W ABOUT 565 MI...905 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H PRESENT MOVEMENT...WNW OR 295 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...973 MB...28.74 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 200 PM PDT (2100 UTC), the center of Hurricane Juliette was located near latitude 19.4 North, longitude 117.8 West. Juliette is moving toward the west-northwest near 7 mph (11 km/h). The hurricane is expected to move west-northwest at a slightly faster forward speed during the next few days. Maximum sustained winds are near 100 mph (155 km/h) with higher gusts. Gradual weakening is forecast during the next several days and Juliette is predicted to weaken to a tropical storm Thursday night. Hurricane-force winds extend outward up to 30 miles (45 km) from the center and tropical-storm-force winds extend outward up to 115 miles (185 km). The estimated minimum central pressure is 973 mb (28.74 inches). HAZARDS AFFECTING LAND ---------------------- None. NEXT ADVISORY ------------- Next complete advisory at 800 PM PDT. $$ Forecaster Brown

...JULIETTE HEADING TOWARD COOLER WATERS... As of 2:00 PM PDT Wed Sep 4 the center of Juliette was located near 19.4, -117.8 with movement WNW at 7 mph. The minimum central pressure was 973 mb with maximum sustained winds of about 100 mph.

Issued at 2100 UTC WED SEP 04 2019 000 WTPZ21 KNHC 042037 TCMEP1 HURRICANE JULIETTE FORECAST/ADVISORY NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL EP112019 2100 UTC WED SEP 04 2019 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. HURRICANE CENTER LOCATED NEAR 19.4N 117.8W AT 04/2100Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 6 KT ESTIMATED MINIMUM CENTRAL PRESSURE 973 MB EYE DIAMETER 25 NM MAX SUSTAINED WINDS 85 KT WITH GUSTS TO 105 KT. 64 KT....... 25NE 20SE 20SW 25NW. 50 KT....... 50NE 50SE 30SW 50NW. 34 KT.......100NE 90SE 90SW 100NW. 12 FT SEAS..150NE 150SE 180SW 180NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 19.4N 117.8W AT 04/2100Z AT 04/1800Z CENTER WAS LOCATED NEAR 19.2N 117.5W FORECAST VALID 05/0600Z 20.0N 118.9W MAX WIND 75 KT...GUSTS 90 KT. 64 KT... 25NE 20SE 20SW 25NW. 50 KT... 50NE 50SE 30SW 50NW. 34 KT...100NE 90SE 90SW 100NW. FORECAST VALID 05/1800Z 21.1N 120.5W MAX WIND 70 KT...GUSTS 85 KT. 64 KT... 25NE 20SE 20SW 25NW. 50 KT... 50NE 50SE 30SW 50NW. 34 KT...100NE 90SE 90SW 100NW. FORECAST VALID 06/0600Z 22.1N 122.4W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 40NE 40SE 30SW 40NW. 34 KT... 90NE 80SE 70SW 90NW. FORECAST VALID 06/1800Z 23.0N 124.4W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 40NE 30SE 20SW 30NW. 34 KT... 80NE 70SE 60SW 80NW. FORECAST VALID 07/1800Z 23.6N 128.1W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 60NE 50SE 40SW 60NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 150 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 08/1800Z 23.2N 131.5W MAX WIND 30 KT...GUSTS 40 KT. OUTLOOK VALID 09/1800Z 22.8N 135.5W...POST-TROP/REMNT LOW MAX WIND 30 KT...GUSTS 40 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 19.4N 117.8W NEXT ADVISORY AT 05/0300Z $$ FORECASTER BROWN

As drought conditions persist and expand, Texans were urged to be particularly careful with fire. North Texas e-News (Fannin, Texas), Aug. 27, 2019

The dry conditions led the Forest Service on Aug. 29 to enact stage 1 fire restrictions in the Arapaho and Roosevelt National Forests in Boulder, Gilpin, Clear Creek and Park counties. KCNC-TV CBS 4 Denver (Colo.), Aug. 30, 2019

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 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