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TROPICAL STORM ALMA DISCUSSION NUMBER  10
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT SUN MAY 26 2002
 
VISIBLE AND INFRARED SATELLITE IMAGERY INDICATE ALMA HAS BECOME A 
LITTLE BETTER ORGANIZED DURING THE PAST 6 HOURS...BUT THE CYCLONE IS 
STILL EXPERIENCING SOME EASTERLY UPPER-LEVEL SHEAR AND DRY AIR 
ENTRAINMENT INTO THE NORTHEAST QUADRANT AS SEEN IN WATER VAPOR 
IMAGERY. THE RESULT HAS BEEN A PARTIAL EXPOSURE OF THE LOW-LEVEL 
CIRCULATION TO THE NORTHEAST AT TIMES. THE INITIAL INTENSITY 
ESTIMATE OF 35 KT IS BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF 
T2.5...OR 35 KT...FROM BOTH TAFB AND SAB. UPPER-LEVEL OUTFLOW IS  
GOOD IN ALL QUADRANTS EXCEPT RESTRICTED TO THE NORTHEAST.

THE INITIAL MOTION ESTIMATE IS 270/09. THERE IS CONSIDERABLE 
UNCERTAINTY IN THE EXACT LOCATION OF THE CENTER. I HAVE KEPT THE 
CENTER TUCKED IN CLOSE TO THE SOUTHEAST EDGE OF A SMALL BURST OF 
-80C CONVECTION THAT HAS FIRED UP DURING THE PAST 3 HOURS NEAR THE 
OLD CENTER LCOATION. HOWEVER...THE BEST MID-LEVEL CIRCULATION 
APPEARS TO BE LOCATED FARTHER TO SOUTH BELOW 10N LATITUDE. AS 
SUCH...THERE MAY BE SOME ERRATIC MOTION DURING THE NIGHTTIME HOURS 
WHEN THE CENTER MAY REDEVELOP FARTHER SOUTH WITHIN THE CONVECTIVE 
CLOUD MASS AND ALSO DUE TO INFRARED-ONLY IMAGERY MAKING CENTER 
FIXING DIFFICULT. HAVING SAID THAT...THE AVN/GFS AND AVN/GFS 
ENSEMBLE SOLUTIONS WERE CLOSELY FOLLOWED GIVEN THEIR RECENT 
PERFORMANCE. NOGAPS AND THE UKMET MODELS TAKE ALMA SLOWLY TO THE 
WEST-NORTHWEST AND NORTHWEST THROUGH 48 HOURS AND THEN BEGIN TO HINT 
AT RECURVATURE BY 72 HOURS...WHICH SEEMS PREMATURE AT THIS POINT IN 
TIME GIVEN THE SIGNIFICNAT WESTWARD PUSH NOTED IN WATER VAPOR 
IMAGERY. THE GFDL IS BETWEEN THE AVN/GFS AND UKMET/NOGAPS 
SOLUTIONS...BUT IS CLOSER TO THE OFFICIAL FORECAST THROUGH 48 HOURS. 
THEREFORE...THE OFFICIAL FORECAST IS SLIGHTLY SOUTH BUT VERY CLOSE 
TO THE PREVIOUS FORECAST TRACK.
 
DURING THE PAST 12 HOURS...WATER VAPOR IMAGERY INDICATES THE 
EASTERLY VERTICAL SHEAR AND DRY AIR ENTRAINMENT THAT HAS ERODED THE 
CONVECTION IN THE NORTHEAST QUADRANT HAS WEAKENED CONSIDERABLY. IN 
FACT...NEW CONVECTION HAS BEEN NOTED DEVELOPING TO THE EAST OF THE 
CENTER AND HAS BEEN MOVING IN THE GENERAL DIRECTION OF THE NORTHEAST 
QUADRANT. GIVEN THE RECENT INCREASE IN CONVECTION...THE IMPROVING 
UPPER-LEVEL OUTFLOW PATTERN...AND SEA-SURFACE TEMPERATURES NEAR 
30C...STEADY INTENSIFICATION SEEMS REASONABLE. THE SHIPS INTENSITY 
MODEL BRINGS ALMA UP TO HURRICANE STRENGTH IN 48 HOURS AND TO 76 KT 
IN 72 HOURS...AND THIS GENERAL INTENSIFICATION TREND WAS FOLLOWED.
 
FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     27/0300Z 10.7N 107.0W    35 KTS
12HR VT     27/1200Z 10.9N 108.4W    40 KTS
24HR VT     28/0000Z 11.0N 110.0W    45 KTS
36HR VT     28/1200Z 11.2N 111.6W    50 KTS
48HR VT     29/0000Z 11.5N 113.0W    60 KTS
72HR VT     30/0000Z 13.0N 115.0W    70 KTS
 
 
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