WDPN31 PGTW 260300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 02W WARNING NR 18//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
OVER THE PAST 12 HOURS, TD 02W HAS WEAKENED UNDER INCREASED VERTICAL 
WIND SHEAR AND HAS DRIFTED NORTH TOWARDS THE APPROACHING BAROCLINIC 
ZONE EVIDENT IN ANIMATED MULTISPECTRAL IMAGERY. WHILE THE LOW LEVEL 
CIRCULATION CENTER (LLCC) WAS SHEARED FROM MAIN CONVECTION AT THE 
BEGINNING OF THE PERIOD, THE SYSTEM HAS RE-DEVELOPED CENTRAL 
CONVECTION OVER THE LAST FEW HOURS, POSSIBLY DUE TO AN ENHANCED 
THERMAL GRADIENT CAUSED BY THE GRADUAL ENTRAINMENT OF COOLER AIR FRO 
THE NORTHWEST. HOWEVER, THE DEEP CONVECTION IS STILL STREAMING OFF 
TO THE NORTHEAST DUE TO GREATER THAN 30 KNOTS OF VERTICAL WIND 
SHEAR, LEAVING THE LLCC PARTIALLY EXPOSED. THE CURRENT POSITION IS 
BASED ON A 252326Z TRMM MICROWAVE IMAGE AND THE CURRENT INTENSITY IS 
BASED ON DVORAK ESTIMATES FROM PGTW, RJTD, AND KNES RANGING FROM 30 
TO 35 KNOTS.
3. FORECAST REASONING
    A. THE FORECAST PHILOSOPHY HAS NOT SIGNIFICANTLY CHANGED SINCE 
THE PREVIOUS PROGNOSTIC REASONING BULLETIN.
    B. TD 02W IS STILL FORECAST TO DRIFT POLEWARD IN A WEAKENED 
STEERING ENVIRONMENT BEFORE DISSIPATING WITHIN THE NEXT 12 TO 24 
HOURS AS EXCESSIVE VERTICAL WIND SHEAR FURTHER ERODES THE SYSTEM'S 
VERTICAL STRUCTURE AND VERY WEAK WARM CORE. WHILE THE FORECAST SIX 
HOURS AGO CALLED FOR THE SYSTEM TO TURN MORE SHARPLY TO THE WEST 
WITH THE LOW-LEVEL NORTHEASTERLY FLOW (DUE TO ITS POSITION RELATIVE 
TO A SHEAR LINE CAUSED BY THE PASSING FRONT), CURRENT MOTION SINCE 
THE LAST FORECAST SUGGESTS THE SYSTEM WILL DRIFT MORE NORTH-
NORTHWESTWARD ALONG THE BAROCLINIC ZONE. 0HOWEVER, THE POSSIBILITY 
THAT THE SYSTEM COULD EVENTUALLY TURN WITH THE NORTHEASTERLY FLOW 
STILL EXISTS.//
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