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TROPICAL DEPRESSION HERNAN DISCUSSION NUMBER  28
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT THU SEP 05 2002
 
VISIBLE AND INFRARED SATELLITE IMAGERY INDICATE THE UPPER-LEVEL 
CIRCULATION HAS SEPARATED FROM THE LOW-LEVEL CIRCULATION AND IS 
DISPLACED ABOUT 120 NMI SOUTHEAST OF THE EXPOSED LOW-LEVEL CENTER. 
THE INITIAL INTENSITY IS HELD AT 30 KT BASED ON A DVORAK CURRENT 
INTENSITY ESTIMATE OF 30 KT FROM TAFB. 
 
THE INITIAL MOTION ESTIMATE IS 360/04. NOW THAT THE LOW-LEVEL CENTER 
HAS DECOUPLED FROM THE MID- AND UPPER-LEVEL CIRCULATION...THE 
DOMINANT STEERING FLOW SHOULD BE THE LOW-LEVEL EASTERLIES. THE 
SUBTROPICAL RIDGE TO THE NORTH IS WEAK WHICH MAY RESULT IN SOME SLOW 
ERRATIC MOTION FOR THE NEXT 12 HOURS OR SO. AFTER THAT...ALL OF THE 
GLOBAL MODELS AGREE THAT RIDGING WILL BUILD IN TO THE EAST OF HERNAN 
WHICH SHOULD HELP TO NUDGE THE DYING CYCLONE ON A WESTWARD TRACK. 
THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS FORECAST AND 
IS CLOSE TO THE AVN AND UKMET SOLUTIONS.

SINCE HERNAN HAS BEEN SHEARED APART AND IS OVER SUB-22C SST WATER... 
RAPID WEAKENING IS EXPECTED AND THE SYSTEM MAY BECOME A 
NON-CONVECTIVE REMNANT LOW WITHIN 12 HOURS. HOWEVER...I HAVE OPTED 
TO HOLD THE INTENSITY UP A LITTLE IN CASE A SMALL CONVECTIVE BURST 
OCCURS LATER TONIGHT NEAR THE LOW-LEVEL CENTER.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     06/0300Z 23.5N 124.3W    30 KTS
12HR VT     06/1200Z 24.0N 124.1W    25 KTS...DISSIPATING
24HR VT     07/0000Z 24.2N 125.0W    25 KTS...REMNANT LOW
36HR VT     07/1200Z 23.7N 126.0W    20 KTS...REMNANT LOW
48HR VT     08/0000Z...DISSIPATED
 
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