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TROPICAL STORM AGATHA DISCUSSION NUMBER  10
NATIONAL WEATHER SERVICE MIAMI FL
2 PM PDT SAT JUN 13 1998
 
THE INITIAL MOTION ESTIMATE IS 300/18 KNOTS...REPRESENTING A 5 KNOT
INCREASE FROM THE LAST ADVISORY. LBAR WAS THE ONLY MODEL TO PICK UP
ON THIS ACCELERATION. SATELLITE-BASED FIXES FROM TAFB AND SAB ARE
IN GOOD AGREEMENT. THE 18Z AVIATION-BASED BAM TRACK MODELS CONTINUE
TO INSIST ON A SOUTHWEST MOTION BY 24 HOURS. THE REMAINDER OF THE
GUIDANCE SHOWS A GENERAL NORTHWEST MOTION...AND IS THE OFFICIAL
FORECAST REFLECTS THIS. THE PRIMARY DISCREPANCY IS WITH THE FORWARD
SPEED. THE OFFICIAL FORECAST CALLS FOR A GRADUAL DECELERATION AS
THE MEAN STEERING DIMINISHES...IN CLOSEST AGREEMENT WITH LBAR. THE
GFDL DISSIPATES THE SYSTEM BY 48 HOURS. 
 
SATELLITE-BASED DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE
3.5+ AND 3.0 RESPECTIVELY. THE INITIAL INTENSITY IS INCREASED TO
55 KNOTS. THE TAFB ANALYST NOTED THE DEVELOPMENT OF A POSSIBLE
WARM SPOT IN SATELLITE IMAGERY DURING THE LAST SEVERAL HOURS. THE
OFFICIAL FORECAST KEEPS THE SYSTEM AT 55 KNOTS THROUGH 24 HOURS 
THEN GRADUALLY WEAKENS IT AS IT MOVES INTO COOLER WATERS.      
 
THE 34 KNOT WIND RADII HAS BEEN EXPANDED TO 120 NM IN THE NORTHWEST
QUADRANT BASED ON A 18Z SHIP DATA.  ALL OTHER RADII REMAIN
UNCHANGED.

GUINEY/LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     13/2100Z 15.7N 115.7W    55 KTS
12HR VT     14/0600Z 16.7N 118.0W    55 KTS
24HR VT     14/1800Z 17.8N 120.6W    45 KTS
36HR VT     15/0600Z 18.9N 122.6W    35 KTS
48HR VT     15/1800Z 20.0N 124.0W    30 KTS
72HR VT     16/1800Z 21.5N 126.0W    25 KTS...DISSIPATING
 
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