Compact News: NOAA's National Weather Service SPC Tornado/Severe Thunderstorm Watches Update

Wednesday, September 22, 2010

NOAA's National Weather Service SPC Tornado/Severe Thunderstorm Watches Update

SPC Tornado Watch 684
Wed, 22 Sep 2010 19:00:05 -0500

URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 684 NWS STORM PREDICTION CENTER NORMAN OK 400 PM CDT WED SEP 22 2010 THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF NORTHERN AND WESTERN NEBRASKA SOUTHEAST SOUTH DAKOTA EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 400 PM UNTIL 1100 PM CDT. TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES EAST SOUTHEAST OF YANKTON SOUTH DAKOTA TO 60 MILES SOUTHWEST OF MULLEN NEBRASKA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4). REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. OTHER WATCH INFORMATION...CONTINUE...WW 680...WW 681...WW 682...WW 683... DISCUSSION...APPROACH OF UPSTREAM IMPULSE FROM THE CNTRL ROCKIES IS EXPECTED TO SUPPORT AN INCREASE IN TSTMS LATE THIS AFTERNOON INTO EVENING FROM VICINITY OF THE WARM FRONT OVER NRN NEB SWWD ALONG LEE TROUGH INTO WRN NEB. BASED ON 18Z LBF/20Z OAX SOUNDINGS...AMBIENT AIR MASS IS MOIST AND MODERATELY UNSTABLE WITH MLCAPE OF 2000-3000 J/KG AND A DECREASING CAP. THE STRONGEST LOW-LEVEL SHEAR AND ASSOCIATED TORNADO THREAT IS EXPECTED ALONG THE WARM FRONT THIS EVENING. HOWEVER...SUPERCELLS CAPABLE OF A TORNADO OR TWO WILL BE POSSIBLE WITH ANY STORMS THAT CAN DEVELOP AND BECOME SUSTAINED ALONG THE LEE TROUGH. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION VECTOR 25030. ...MEAD

SPC Severe Thunderstorm Watch 683
Wed, 22 Sep 2010 19:00:09 -0500

URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 683 NWS STORM PREDICTION CENTER NORMAN OK 345 PM EDT WED SEP 22 2010 THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF WESTERN CONNECTICUT DELAWARE EASTERN MARYLAND NEW JERSEY SOUTHEAST NEW YORK EASTERN PENNSYLVANIA COASTAL WATERS EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 345 PM UNTIL 1100 PM EDT. HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH NORTHWEST OF POUGHKEEPSIE NEW YORK TO 40 MILES SOUTH OF DOVER DELAWARE. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3). 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. OTHER WATCH INFORMATION...CONTINUE...WW 680...WW 681...WW 682... DISCUSSION...TSTMS ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON ALONG/E OF LEE TROUGH AND SYNOPTIC COLD FRONT WITHIN A WARM...MODERATELY UNSTABLE AIR MASS WITH SBCAPE VALUES OF 1000-2000 J/KG. REGIONAL VWPS AND LATEST RUC OBJECTIVE FIELDS SUGGEST THAT DEEP WLY WIND FIELD DECREASES WITH SWD EXTENT...THOUGH SUFFICIENT VERTICAL SHEAR WILL EXIST ACROSS WW AREA TO SUPPORT ORGANIZE STORM MODES INCLUDING SUPERCELL AND BOWING STRUCTURES WITH A RISK FOR MAINLY DAMAGING WIND GUSTS. 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 500. MEAN STORM MOTION VECTOR 27030. ...MEAD

SPC Severe Thunderstorm Watch 682
Wed, 22 Sep 2010 19:00:12 -0500

URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 682 NWS STORM PREDICTION CENTER NORMAN OK 245 PM EDT WED SEP 22 2010 THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF DISTRICT OF COLUMBIA MARYLAND NORTHERN VIRGINIA EASTERN WEST VIRGINIA PANHANDLE COASTAL WATERS EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 245 PM UNTIL 1000 PM EDT. HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH NORTHWEST OF BALTIMORE MARYLAND TO 20 MILES EAST SOUTHEAST OF CHARLOTTESVILLE VIRGINIA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2). 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. OTHER WATCH INFORMATION...CONTINUE...WW 680...WW 681... DISCUSSION...TSTMS ARE EXPECTED TO INTENSIFY ALONG LEE TROUGH AND MOVE INTO THE REGION FROM THE W/NW AS AIR MASS CONTINUES TO WARM/DESTABILIZE. WHILE AREA RESIDES ALONG SRN FRINGE OF STRONGER...ZONAL MID AND HIGH-LEVEL WIND FIELD...SUFFICIENT VERTICAL SHEAR WILL EXIST TO SUPPORT ORGANIZED STORMS INCLUDING MULTICELLS AND BOWING LINE SEGMENTS WITH A RISK FOR DAMAGING WIND GUSTS. 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 500. MEAN STORM MOTION VECTOR 27025. ...MEAD

SPC Severe Thunderstorm Watch 681
Wed, 22 Sep 2010 19:00:16 -0500

URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 681 NWS STORM PREDICTION CENTER NORMAN OK 235 PM EDT WED SEP 22 2010 THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF WESTERN MARYLAND PANHANDLE SOUTHEAST OHIO WESTERN AND CENTRAL PENNSYLVANIA NORTHERN WEST VIRGINIA EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 235 PM UNTIL 1000 PM EDT. HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES WEST OF WHEELING WEST VIRGINIA TO 35 MILES SOUTHEAST OF WILLIAMSPORT PENNSYLVANIA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1). 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. OTHER WATCH INFORMATION...CONTINUE...WW 680... DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY THIS AFTERNOON WITHIN A STEEP LOW-LEVEL LAPSE RATE...MODERATELY UNSTABLE ENVIRONMENT WITH MLCAPE OF 1000-1500 J/KG. REGIONAL VWPS INDICATE MODESTLY STRONG WLY TROPOSPHERIC FLOW WHICH WILL BE SUPPORTIVE OF SPLITTING SUPERCELL STRUCTURES AND BOWING LINE SEGMENTS WITH THE PRIMARY HAZARD BEING DAMAGING WIND GUSTS. 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 500. MEAN STORM MOTION VECTOR 27035. ...MEAD

SPC Severe Thunderstorm Watch 680
Wed, 22 Sep 2010 17:38:04 -0500

URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 680 NWS STORM PREDICTION CENTER NORMAN OK 1110 AM CDT WED SEP 22 2010 THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF NORTHWEST IOWA SOUTHWEST MINNESOTA NORTHEAST NEBRASKA SOUTHEAST SOUTH DAKOTA EFFECTIVE THIS WEDNESDAY MORNING AND EVENING FROM 1110 AM UNTIL 600 PM CDT. HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST OF YANKTON SOUTH DAKOTA TO 25 MILES EAST NORTHEAST OF FAIRMONT MINNESOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0). 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. DISCUSSION...THE COMBINATION OF ENEWD-PROGRESSING MIDLEVEL IMPULSE AND AN INFLUX OF A WARM/MOIST AIR MASS ALONG 40-50 KT LLJ SHOULD SUSTAIN ELEVATED SEVERE TSTMS THROUGH THE DAY TO THE N OF SURFACE WARM FRONT. STEEP MIDLEVEL LAPSE RATES...MUCAPE OF 2000-3000 J/KG AND 45-55 KT OF EFFECTIVE BULK SHEAR WILL BE MORE THAN SUFFICIENT FOR SUPERCELLS CAPABLE OF MAINLY LARGE HAIL. AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION VECTOR 25030. ...MEAD

SPC Tornado Watch 684 Status Reports
Wed, 22 Sep 2010 19:00:07 -0500

  STATUS REPORT ON WW 684  THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.  ..EDWARDS..09/22/10  ATTN...WFO...OAX...LBF...FSD...GID...   STATUS REPORT FOR WT 684   SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS   NEC003-005-009-015-017-027-029-031-039-041-043-047-051-063-071- 075-085-089-091-101-103-107-111-113-115-117-119-135-139-149-167- 171-173-179-183-230040-  NE  .    NEBRASKA COUNTIES INCLUDED ARE  ANTELOPE             ARTHUR              BLAINE               BOYD                 BROWN               CEDAR                CHASE                CHERRY              CUMING               CUSTER               DAKOTA              DAWSON               DIXON                FRONTIER            GARFIELD             GRANT                HAYES               HOLT                 HOOKER               KEITH               KEYA PAHA            KNOX                 LINCOLN             LOGAN                LOUP                 MCPHERSON           MADISON              PERKINS              PIERCE              ROCK                 STANTON              THOMAS              THURSTON             WAYNE                WHEELER                SDC009-023-027-043-053-067-083-125-127-135-230040-  SD  .    SOUTH DAKOTA COUNTIES INCLUDED ARE

SPC Severe Thunderstorm Watch 683 Status Reports
Wed, 22 Sep 2010 19:00:11 -0500

  STATUS REPORT ON WW 683  SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 W ABE TO 5 S POU TO 10 S BDL.  ..HURLBUT..09/22/10  ATTN...WFO...OKX...ALY...PHI...BGM...   STATUS REPORT FOR WS 683   SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS   CTC001-009-230040-  CT  .    CONNECTICUT COUNTIES INCLUDED ARE  FAIRFIELD            NEW HAVEN              DEC001-003-005-230040-  DE  .    DELAWARE COUNTIES INCLUDED ARE  KENT                 NEW CASTLE          SUSSEX                 MDC011-015-029-035-041-230040-  MD  .    MARYLAND COUNTIES INCLUDED ARE  CAROLINE             CECIL               KENT                 QUEEN ANNE'S         TALBOT

SPC Severe Thunderstorm Watch 682 Status Reports
Wed, 22 Sep 2010 19:00:14 -0500

  STATUS REPORT ON WW 682  SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NW SBY TO 40 SW MRB.  ..HURLBUT..09/22/10  ATTN...WFO...LWX...   STATUS REPORT FOR WS 682   SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS   DCC001-230040-  DC  .    DISTRICT OF COLUMBIA COUNTIES INCLUDED ARE  DISTRICT OF COLUMBIA    MDC001-003-005-013-021-025-027-031-033-043-510-230040-  MD  .    MARYLAND COUNTIES INCLUDED ARE  ALLEGANY             ANNE ARUNDEL        BALTIMORE            CARROLL              FREDERICK           HARFORD              HOWARD               MONTGOMERY          PRINCE GEORGES       WASHINGTON              MARYLAND INDEPENDENT CITIES INCLUDED ARE  BALTIMORE CITY          VAC013-043-069-107-510-610-840-230040-

SPC Severe Thunderstorm Watch 681 Status Reports
Wed, 22 Sep 2010 19:00:18 -0500

  STATUS REPORT ON WW 681  SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 SW ZZV TO 20 S LBE TO 25 SSE AOO TO 25 W CXY TO 25 SW AVP.  ..HURLBUT..09/22/10  ATTN...WFO...PBZ...RLX...CTP...   STATUS REPORT FOR WS 681   SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS   MDC023-230040-  MD  .    MARYLAND COUNTIES INCLUDED ARE  GARRETT                 OHC009-111-115-121-167-230040-  OH  .    OHIO COUNTIES INCLUDED ARE  ATHENS               MONROE              MORGAN               NOBLE                WASHINGTON             PAC001-009-043-051-055-057-059-071-075-107-111-133-230040-  PA  .    PENNSYLVANIA COUNTIES INCLUDED ARE  ADAMS                BEDFORD             DAUPHIN              FAYETTE              FRANKLIN            FULTON               GREENE               LANCASTER           LEBANON

SPC Severe Thunderstorm Watch 680 Status Reports
Wed, 22 Sep 2010 17:38:05 -0500

  STATUS REPORT ON WW 680  SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 SSE SUX TO 15 E FSD TO 10 SW BKX.  PORTIONS WW 680 MAY BE LOCALLY EXTENDED BEFORE IT IS SCHEDULED TO EXPIRE AT 222300Z.  FOR ADDITIONAL INFORMATION SEE MESOSCALE SPC DISCUSSION 1889.  ..EDWARDS..09/22/10  ATTN...WFO...FSD...DMX...MPX...OAX...   STATUS REPORT FOR WS 680   SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS   IAC021-035-041-059-063-091-093-109-119-141-143-147-149-151-167- 193-222300-  IA  .    IOWA COUNTIES INCLUDED ARE  BUENA VISTA          CHEROKEE            CLAY                 DICKINSON            EMMET               HUMBOLDT             IDA                  KOSSUTH             LYON                 O'BRIEN              OSCEOLA             PALO ALTO            PLYMOUTH             POCAHONTAS          SIOUX                WOODBURY                MNC013-015-033-043-063-081-083-085-091-101-103-105-117-127-129- 133-143-165-173-222300-  MN  .    MINNESOTA COUNTIES INCLUDED ARE  BLUE EARTH           BROWN               COTTONWOOD

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