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TROPICAL STORM ALMA DISCUSSION NUMBER  13
NATIONAL WEATHER SERVICE MIAMI FL
2 PM PDT MON MAY 27 2002
 
THE LOW LEVEL CENTER CONTINUES TO BE DIFFICULT TO LOCATE IN THE
VISIBLE IMAGERY BUT THERE WAS A HINT OF IT ON THE EAST SIDE OF THE
DEEP CONVECTION JUST BEFORE MID-LEVEL CLOUDS OBSCURED IT.
BECAUSE OF THIS...THE SATELLITE INTENSITY ESTIMATE FROM SAB
HAS INCREASED AND IS NOW 55 KTS WHILE TAFB REMAINS AT 45 KTS.  THE
INITIAL INTENSITY IS INCREASED TO 45 KT.

THE INITIAL MOTION IS ESTIMATED AT 290/9.  THE SYNOPTIC REASONING
REMAINS THE SAME...ALMA WILL TRACK WEST AND WEST-NORTHWESTWARD SOUTH
OF A MID/UPPER-LEVEL RIDGE.  LARGE-SCALE MODELS AGREE THAT IN TIME
THE RIDGE WILL WEAKEN AS A CUT-OFF LOW FORMS NEAR SOUTHERN
CALIFORNIA AND MOVES SOUTHWESTWARD.  THE TRACK GUIDANCE RESPONDS TO
THIS DEVELOPMENT BY TURNING ALMA NORTHWESTWARD AND NORTHWARD.  THE
MODELS WHICH WERE DIVIDED INTO TWO CAMPS IN PREVIOUS PACKAGES ARE
NOW CONVERGING TOWARD A MORE COMMON SOLUTION BUT STILL HAVE A LARGE
SPREAD WITH THE UKMET THE EASTERN MOST AND LBAR AND BAMS THE WESTERN
MOST.  THE OFFICIAL FORECAST WILL STILL BE WEIGHTED TOWARD THE
WESTERN MOST TRACKS AND WILL BE NORTH AND EAST OF THE PREVIOUS
OFFICIAL TRACK.

SATELLITE PRODUCTS FROM CIMSS AT THE UNIVERSITY OF WISCONSIN SUGGEST
THAT THE EASTERLY SHEAR HAS WEAKENED OVER ALMA...GOING FROM ABOUT 15
KTS OVER THE PAST 24 HOURS TO ABOUT 10 KTS AT THE 1500 UTC
ANALYSIS...POSSIBLY CREATING A MORE FAVORABLE ENVIRONMENT FOR
INTENSIFICATION.  THE INTENSITY FORECAST IS NOW MORE IN-LINE WITH 
THE SHIPS FORECAST AND BRINGS THE SYSTEM TO A HURRICANE IN ABOUT 30 
TO 36 HOURS.  GRADUAL RECURVATURE INTO A STRONGER SHEAR ENVIRONMENT 
AND COOLER SSTS WILL WEAKEN THE SYSTEM AT THE LATER FORECAST PERIOD.

THE 12 FOOT SEAS RADII ON THE EAST SIDE OF THE SYSTEM WERE MODIFIED 
BASED UPON OBSERVATIONS FROM SHIP ZQTP2.

FORECASTER JARVINEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     27/2100Z 11.4N 109.9W    45 KTS
12HR VT     28/0600Z 11.9N 111.3W    50 KTS
24HR VT     28/1800Z 12.7N 113.0W    60 KTS
36HR VT     29/0600Z 13.4N 114.0W    70 KTS
48HR VT     29/1800Z 14.4N 114.7W    75 KTS
72HR VT     30/1800Z 17.0N 114.7W    70 KTS
 
 
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