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Severe Thunderstorm Watch 564
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WW0564 Radar
Hazard Tornadoes EF2+ Tornadoes
Likelihood Very Low Very Low
Severe Wind 65 kt+ Wind
Moderate Low
Severe Hail 2"+ Hail
Low Low

Note:  The expiration time in the watch graphic is amended if the watch is replaced, cancelled or extended.
Note: Click for Watch Status Reports.
   SEL4
   
   URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 564
   NWS STORM PREDICTION CENTER NORMAN OK
   340 PM EDT SUN AUG 5 2012
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          DISTRICT OF COLUMBIA
          NORTHERN DELAWARE
          CENTRAL MARYLAND
          WESTERN NEW JERSEY
          SOUTHEAST PENNSYLVANIA
          NORTHERN VIRGINIA
          COASTAL WATERS
   
   EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 340 PM UNTIL 900
   PM EDT.
   
   HAIL TO 1 INCH 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 70
   STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES SOUTH
   SOUTHWEST OF WASHINGTON DISTRICT OF COLUM TO 20 MILES NORTH OF
   ALLENTOWN PENNSYLVANIA.  FOR A COMPLETE DEPICTION OF THE WATCH
   SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).
   
   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 563...
   
   DISCUSSION...CONVECTION FORMING OVER E EDGE OF THE HIGHER TERRAIN
   FROM NRN VA INTO SE PA SHOULD CONTINUE TO SPREAD EWD THROUGH THE
   AFTERNOON/EVENING.  MODERATE INSTABILITY IS PRESENT AHEAD OF THESE
   STORMS...WHERE SURFACE TEMPERATURES HAVE WARMED INTO THE LOW 90S
   WITH DEWPOINTS IN THE LOW 70S.  GIVEN THE COMBINATION OF MLCAPE OF
   1500-2500 J/KG PER THE 18Z IAD SOUNDING...AND ROUGHLY 30 KT
   LOW-MIDLEVEL SWLY FLOW...THE STRONGER STORMS COULD PRODUCE A FEW
   DAMAGING OUTFLOW GUSTS THROUGH THIS EVENING.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.
   A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION
   VECTOR 26020.
   
   
   ...THOMPSON
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