081 
 WTPZ43 KNHC 130831
 TCDEP3
 TROPICAL STORM BLAS DISCUSSION NUMBER   4
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 2 AM PDT TUE JUL 13 2004
  
 BLAS IS STRENGTHENING.  A QUIKSCAT PASS AT 01Z CONTAINED 50 KT
 VECTORS BELIEVED TO BE RELIABLE...AND IS CONSISTENT WITH THE MOST
 RECENT 3.0 DVORAK CLASSIFICATION FROM TAFB.  THE INITIAL INTENSITY
 ESTIMATE IS 50 KT.  OVER THE PAST SEVERAL HOURS...DEEP CONVECTION
 HAS BEEN INCREASING MARKEDLY NEAR OR OVER THE CENTER AND DECREASING
 ELSEWHERE.  THIS EVOLUTION WOULD FAVOR CONTINUED STRENGTHENING IN
 THE SHORT TERM.  BOTH THE SHIPS AND GFDL GUIDANCE BRING BLAS TO
 JUST SHY OF HURRICANE STRENGTH WITHIN THE NEXT 18-24 HOURS.  THE
 OFFICIAL FORECAST FOLLOWS SUIT...BUT IT IS QUITE POSSIBLE THAT BLAS
 WILL BECOME A HURRICANE BEFORE IT REACHES COOLER WATERS IN 24 HOURS
 AND BEGINS TO DECAY.  
 
 THE INITIAL MOTION ESTIMATE IS 310/14.  THE PRIMARY STEERING FEATURE
 IS CURRENTLY THE MID-LEVEL HIGH OVER THE SOUTHWESTERN UNITED
 STATES.  THE GFS AND NOGAPS MODELS HAVE BACKED OFF SOME ON THE
 DEVELOPMENT OF A SECOND CYCLONE TO THE SOUTHWEST OF BLAS...ALTHOUGH
 THE 00Z UKMET STILL FAVORS THIS SCENARIO AND CONSEQUENTLY IS MUCH
 SLOWER AND FARTHER NORTH THAN THE OTHER MODELS.  CONSIDERING THAT
 THE GUIDANCE GENERALLY MAY STILL BE TOO STRONG WITH THE SECOND
 SYSTEM...THE OFFICIAL FORECAST AGAIN LIES ON THE LEFT SIDE OF THE
 GUIDANCE ENVELOPE AND THE GUNA DYNAMICAL MODEL CONSENSUS.  THE
 OFFICIAL FORECAST IS IN BEST AGREEMENT WITH THE GFS...AND IS JUST A
 LITTLE BIT FASTER THAN THE PREVIOUS ADVISORY.
  
 INITIAL WIND RADII HAVE BEEN ADJUSTED OUTWARD BASED ON THE 01Z
 QUIKSCAT PASS...ALTHOUGH THE CONSOLIDATION OF THE CONVECTION NOTED
 IN RECENT SATELLITE IMAGERY SUGGESTS THAT THE RADII MAY SOON BEGIN
 TO CONTRACT.
  
 FORECASTER FRANKLIN
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      13/0900Z 17.5N 109.6W    50 KT
  12HR VT     13/1800Z 18.9N 111.3W    60 KT
  24HR VT     14/0600Z 20.4N 113.8W    60 KT
  36HR VT     14/1800Z 21.4N 116.0W    50 KT
  48HR VT     15/0600Z 22.0N 118.0W    40 KT
  72HR VT     16/0600Z 23.0N 121.5W    30 KT
  96HR VT     17/0600Z 23.5N 125.0W    25 KT...DISSIPATING
 120HR VT     18/0600Z 23.5N 128.5W    20 KT...REMNANT LOW
  
  
 $$