317 
 WTPZ43 KNHC 191437
 TCDEP3
 TROPICAL STORM BLAS DISCUSSION NUMBER   9
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP032010
 800 AM PDT SAT JUN 19 2010
  
 EARLY MORNING VISIBLE SATELLITE IMAGERY SUGGESTS THAT THE CENTER OF
 BLAS IS LOCATED JUST TO THE EAST-NORTHEAST OF THE DEEPEST
 CONVECTION.  THIS IS CONSISTENT WITH THE MORE EASTERLY SHEAR
 ANALYZED OVER THE CYCLONE BY UW-CIMSS.  WITH THE CENTER EMBEDDED
 CLOSER TO THE CONVECTION...DVORAK INTENSITY ESTIMATES HAVE
 INCREASED TO 55 KT FROM TAFB AND SAB...AND THAT IS THE INITIAL
 INTENSITY FOR THIS ADVISORY.  
 
 WITH A LACK OF MICROWAVE IMAGERY OVER THE PAST SEVERAL HOURS THE
 INITIAL MOTION ESTIMATE IS A RATHER UNCERTAIN 280/06.  WHILE THE
 INITIAL POSITION IS A LITTLE SOUTH OF THE PREVIOUS FORECAST...THE
 OVERALL TRACK FORECAST REASONING REMAINS UNCHANGED.  BLAS WILL
 CONTINUE MOVING GENERALLY WESTWARD TO THE SOUTH OF A DEEP-LAYER
 RIDGE OVER THE EASTERN PACIFIC FOR THE NEXT COUPLE OF DAYS WITH A
 SLIGHT INCREASE IN FORWARD SPEED. BY 72 HOURS AND BEYOND...A MOTION
 SOUTH OF DUE WEST IS EXPECTED AS THE WEAKENING CYCLONE IS
 INCREASINGLY STEERED BY THE LOW-LEVEL FLOW.  THE NEW TRACK FORECAST
 IS ADJUSTED SOUTHWARD FROM THE PREVIOUS PACKAGE DUE TO THE MORE
 SOUTHERLY INITIAL POSITION...BUT LIES CLOSE TO THE MIDDLE OF THE
 GUIDANCE ENVELOPE. 
 
 THE INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD TO ACCOUNT FOR THE
 OBSERVED INTENSITY TRENDS...AND SHOWS A PEAK AT 12 HOURS IN
 AGREEMENT WITH THE SHIPS...LGEM...HWRF...AND GFDL.  WHILE NONE OF
 THE GUIDANCE SHOWS BLAS REACHING HURRICANE INTENSITY...THERE IS
 ABOUT A 30 PERCENT CHANCE THAT BLAS COULD BECOME A HURRICANE IN THE
 NEXT 24 HOURS ACCORDING TO PROBABILISTIC GUIDANCE BASED ON
 PREVIOUS NHC FORECAST ERRORS.  SLOW WEAKENING IS FORECAST TO BEGIN
 BY 24 HOURS AS BLAS MOVES OVER COOLER WATERS AND INTO A LESS
 FAVORABLE THERMODYNAMIC ENVIRONMENT.  THE OFFICIAL FORECAST IS CLOSE
 TO THE LGEM GUIDANCE AND IS A LITTLE HIGHER THAN THE PREVIOUS
 PACKAGE.  BLAS SHOULD BECOME A REMNANT LOW IN 4 OR 5 DAYS. 
 
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      19/1500Z 16.3N 109.7W    55 KT
  12HR VT     20/0000Z 16.5N 111.0W    60 KT
  24HR VT     20/1200Z 16.7N 112.8W    55 KT
  36HR VT     21/0000Z 16.9N 114.8W    50 KT
  48HR VT     21/1200Z 17.0N 116.8W    45 KT
  72HR VT     22/1200Z 16.5N 120.5W    35 KT
  96HR VT     23/1200Z 16.0N 124.5W    25 KT
 120HR VT     24/1200Z 15.5N 128.0W    20 KT...POST-TROP/REMNT LOW
  
 $$
 FORECASTER BRENNAN