000
WTPZ43 KNHC 132029
TCDEP3
TROPICAL STORM BLAS DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 PM PDT TUE JUL 13 2004
 
AFTER LOOKING HEALTHY THIS MORNING...BLAS NOW APPEARS TO BE FEELING
THE EFFECTS OF COLDER SEA SURFACE TEMPERATURES.  THE CONVECTIVE
OVERCAST SEEN THIS MORNING HAS BEEN REPLACED BY A LOOSE BANDING
PATTERN...AND THE CONVECTION HAS DECREASED SIGNIFICANTLY IN
COVERAGE AND INTENSITY.  SATELLITE INTENSITY ESTIMATES REMAIN 55 KT
FROM TAFB AND 45 KT FROM SAB AND AFWA.  THE INITIAL INTENSITY
REMAINS 50 KT.

THE INITIAL MOTION IS NOW 310/17...AND THE SHORT-TERM MOTION MIGHT
BE A LITTLE FASTER.  THE OVERALL FORECAST PHILOSOPHY IS UNCHANGED
FROM THE PREVIOUS ADVISORY.  BLAS SHOULD CONTINUE NORTHWESTWARD FOR
THE NEXT 12-24 HR ON THE SOUTHWEST SIDE OF MID-LEVEL RIDGE OVER THE
WESTERN UNITED STATES...THEN DECELERATE AND TURN MORE WESTWARD AS
THE CYCLONE WEAKENS OVER COOLER WATER.  THIS IS THE SCENARIO OF THE
GFS...GFDL...AND NOGAPS.  THE UKMET CONTINUES TO CALL FOR A MORE
NORTHWARD AND SLOWER MOTION.  SINCE THIS MODEL OVER-INITIALIZES THE
DISTURBANCE SOUTHWEST OF BLAS...IT IS BEING DISCOUNTED FOR THIS
FORECAST.  THE FORECAST TRACK IS NUDGED TO THE RIGHT OF THE
PREVIOUS OFFICIAL FORECAST DUE MAINLY TO THE INITIAL POSITION AND
MOTION.

THE FASTER THAN EXPECTED NORTHWESTWARD MOTION HAS BROUGHT BLAS TO
26C AND COLDER SEA SURFACE TEMPERATURES AHEAD OF THE PREVIOUS
SCHEDULE.  THE INTENSITY FORECAST THUS CALLS FOR A FASTER WEAKENING
THAN THE PREVIOUS PACKAGE.  BLAS IS NOW FORECAST TO WEAKEN TO A
DEPRESSION IN 48 HR AND TO A REMNANT LOW BY 96 HR...WITH THE
CIRCULATION DISSIPATING COMPLETELY BY 120 HR.
 
AN AUTOMATED STATION NEAR CABO SAN LUCAS HAS BEEN REPORTING 30-35 KT
SUSTAINED WINDS AT AN ELEVATION OF 225 M.  WHILE THE MAIN CORE OF
WIND ASSOCIATED WITH BLAS IS FORECAST TO STAY OFFSHORE...SQUALLS
WITH GUSTS TO TROPICAL STORM FORCE WILL LIKELY OCCUR OVER PORTIONS
OF SOUTHEN BAJA CALIFORNIA THE REMAINDER OF THIS AFTERNOON AND
TONIGHT.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/2100Z 20.1N 112.7W    50 KT
 12HR VT     14/0600Z 21.4N 114.8W    50 KT
 24HR VT     14/1800Z 22.5N 116.8W    40 KT
 36HR VT     15/0600Z 23.3N 118.9W    35 KT
 48HR VT     15/1800Z 23.7N 120.8W    30 KT
 72HR VT     16/1800Z 24.0N 124.5W    25 KT...DISSIPATING
 96HR VT     17/1800Z 24.0N 127.5W    20 KT...REMNANT LOW
120HR VT     18/1800Z...DISSIPATED
 
 
$$