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HURRICANE ALMA DISCUSSION NUMBER  26
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT THU MAY 30 2002

ALMA HAS BEEN SHOWING SIGNS OF SIGNIFICANT WEAKENING DURING THE PAST 
6 HOURS. THE INNER-CORE CONVECTION HAS BECOME RAGGED AND ELONGATED 
NORTHEAST-SOUTHWEST...WHILE THE EYE HAS DISAPPEARED IN BOTH VISIBLE 
AND INFRARED IMAGERY. THE INITIAL INTENSITY OF 85 KT IS BASED ON A 
BLEND OF DVORAK SATELLITE INTENSITY ESTIMATES RANGING FROM 77 KT TO 
102 KT FROM BOTH TAFB AND SAB...AND 6-HOUR ODT AVERAGE T-NUMBERS 
RANGING FROM T4.7/81 KT CDO AND T5.1/92 KT EYE PATTERNS. OUTFLOW 
REMAINS GOOD TO THE NORTHEAST...BUT POOR AND/OR RESTRICTED ELSEWHERE 
DUE TO MODERATE UPPER-LEVEL SOUTHWESTERLY SHEAR.
 
THE INITIAL MOTION ESTIMATE REMAINS 005/08. ALMA REMAINS ON TRACK SO 
THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK OTHER 
THAN TO SHIFT IT SLIGHTLY NORTHWARD AFTER 36 HOURS. THE UPPER-LEVEL 
LOW SOUTHWEST OF SAN DIEGO CONTINUES TO LIFT NORTHWARD...WHICH IS 
ALLOWING THE SUBTROPICAL RIDGE TO ALSO SHIFT SLOWLY NORTHWARD. AS 
SUCH...THE TRACK OF ALMA IS EXPECTED TO BE A LITTLE FARTHER NORTH 
THAN PREVIOUSLY EXPECTED. THE UKMET...AVN/GFS...AND NOGAPS MODELS 
WANT TO RAPIDLY WEAKEN ALMA AND MAKE IT STATIONARY IN 12 TO 24 HOURS 
AND THEN GRADUALLY DRIFT IT SOUTHWARD. HOWEVER...ALMA HAS A HISTORY 
OF BEING STRONGER THAN WHAT ANY OF THE FORECAST MODELS HAVE BEEN 
FORECASTING...SO I THINK THIS CYCLONE WILL STICK AROUND A LITTLE 
LONGER THAN WHAT THE MAJORITY OF THE MODELS ARE SUGGESTING. THE 
OFFICIAL TRACK IS BETWEEN THE AVN/GFS MODEL AND THE AVN/GFS 
10-MEMBER ENSEMBLE MEAN...AND CLOSE TO THE NAVY COAMPS AND THE DEEP 
BAM MODELS.

DURING THE PAST 9 HOURS...WATER VAPOR AND VISIBLE SATELLITE IMAGERY 
INDICATE A HIGH-LEVEL TROUGH...PROBABLY ABOVE 200 MB...HAS TRAVERSED 
HURRICANE ALMA FROM SOUTHWEST TO NORTHEAST AND DISRUPTED THE 
INNER-CORE CONVECTION. HOWEVER...THIS TROUGH AND ITS ASSOCIATED 
VERTICAL SHEAR IS EXITING THE EASTERN SEMICIRCLE AND SOME OF THE 
EYEWALL CONVECTION HAS STARTED TO MAKE A COMEBACK DURING THE PAST 
HOUR OR SO. AS SUCH...ALMA MAY MAINTAIN SOME OF ITS INTENSITY FOR 
THE NEXT 6 HOURS OR SO AS IT ENTERS THE DIURNAL CONVECTIVE MAXIMUM 
PERIOD...DESPITE MOVING OVER SUB-25C SSTS NOW. THEREFORE...THE 
PREVIOUS INTENSITY FORECAST AND WEAKENING TREND WERE MAINTAINED... 
WHICH IS A LITTLE HIGHER THAN THE SHIPS AND GFDL INTENSITY MODELS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     31/0300Z 17.9N 115.0W    85 KTS
12HR VT     31/1200Z 18.8N 114.9W    75 KTS
24HR VT     01/0000Z 19.4N 114.6W    60 KTS
36HR VT     01/1200Z 19.7N 114.2W    45 KTS
48HR VT     02/0000Z 19.8N 113.7W    35 KTS
72HR VT     03/0000Z 20.0N 112.8W    25 KTS...DISSIPATING
 
 
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