Tropical Storm BLAS
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TROPICAL STORM BLAS DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT WED JUL 14 2004
BLAS CONTINUES TO WEAKEN. ONLY MINIMAL CONVECTION REMAINS WITH THE
CYCLONE...MAINLY IN SMALL PATCHES NEAR THE CENTER AND IN AN OUTER
BAND TO THE EAST AND SOUTHEAST. SATELLITE INTENSITY ESTIMATES ARE
35 KT FROM AFWA...AND 30 KT FROM TAFB AND SAB. THE INITIAL
INTENSITY IS DECREASED TO 35 KT FOR THIS ADVISORY. SEVERAL
MICROWAVE SATELLITE OVERPASSES DURING THE NEXT SEVERAL HOURS SHOULD
PROVIDE BETTER DATA ON THE INTENSITY.
THE INITIAL MOTION IS 305/15. BLAS IS ON THE SOUTHWEST SIDE OF A
LARGE MID-LEVEL RIDGE OVER THE SOUTHWESTERN UNITED STATES AND
HEADING FOR A LARGE DEEP-LAYER TROUGH OVER THE NORTHEASTERN
PACIFIC. IF BLAS WAS A STRONG HURRICANE OVER WARM WATER...IT WOULD
TRY TO RECURVE AHEAD OF THE TROUGH. SINCE IT IS INSTEAD WEAKENING
OVER COLD WATER...THE CYCLONE SHOULD CONTINUE GENERALLY WEST-
NORTHWESTWARD FOR 24 HR. THIS SHOULD BE FOLLOWED BY DECELERATION
AND A GRADUAL TURN TOWARD THE WEST AS BLAS WEAKENS AND THE
LOW-LEVEL RIDGE TO THE NORTH BECOMES THE DOMINANT STEERING
MECHANISM. THIS IS THE SCENARIO OF ALL THE DYNAMICAL MODELS...AND
BASED ON THEM THE OFFICIAL FORECAST IS AN UPDATE OF THE PREVIOUS
FORECAST
BLAS IS NOW OVER 23C SEA SURFACE TEMPERATURES...AND THE WATERS GET
EVEN COLDER ALONG THE FORECAST TRACK. THE CYCLONE SHOULD THUS
WEAKEN TO A REMNANT LOW IN 24-36 HR...IF NOT SOONER. LARGE-SCALE
MODELS SUGGEST THE LOW COULD SURVIVE THROUGH ABOUT 96 HR...AND THIS
IS REFLECTED IN THE FORECAST.
FORECASTER BEVEN
FORECAST POSITIONS AND MAX WINDS
INITIAL 14/1500Z 22.4N 117.2W 35 KT
12HR VT 15/0000Z 23.4N 119.2W 30 KT
24HR VT 15/1200Z 24.0N 121.1W 25 KT...DISSIPATING
36HR VT 16/0000Z 24.5N 123.0W 20 KT...REMNANT LOW
48HR VT 16/1200Z 24.8N 124.7W 20 KT...REMNANT LOW
72HR VT 17/1200Z 25.0N 128.0W 20 KT...REMNANT LOW
96HR VT 18/1200Z 25.0N 130.5W 20 KT...REMNANT LOW
120HR VT 19/1200Z...DISSIPATED
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