April 20: Severe Thunderstorm Watch #5

URGENT - IMMEDIATE BROADCAST REQUESTED
   SEVERE THUNDERSTORM WATCH NUMBER 172
   NWS STORM PREDICTION CENTER NORMAN OK
   405 PM EDT WED APR 20 2011
   
   THE NWS STORM PREDICTION CENTER HAS ISSUED A
   SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
   
          CENTRAL AND EASTERN PENNSYLVANIA
   
   EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 405 PM UNTIL
   1100 PM EDT.
   
   HAIL TO 0.5 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 60
   STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES SOUTHEAST OF
   ALTOONA PENNSYLVANIA TO 45 MILES NORTH OF WILKESBARRE
   PENNSYLVANIA.  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 168...WW 169...WW
   170...WW 171...
   
   DISCUSSION...LOW-TOPPED TSTMS ARE GRADUALLY INTENSIFYING THIS
   AFTERNOON ALONG COLD FRONT PUSHING EWD ACROSS THE REGION.  BREAKS IN
   THE CLOUDS HAVE ALLOWED FOR A CORRIDOR OF STRONGER DIABATIC WARMING
   WHICH IS SUPPORTING SBCAPE OF AROUND 500 J/KG.  GIVEN THE STRONG WLY
   DEEP-LAYER WIND FIELD OBSERVED BY AREA VWPS...THE POTENTIAL WILL
   EXIST FOR SMALL SUPERCELLS OR BOWING STRUCTURES WITH THE PRIMARY
   HAZARD BEING DAMAGING WIND GUSTS.
   
   AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
   TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
   KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 350. MEAN STORM
   MOTION VECTOR 27045.