Tropical Storm TAPAH Advisory mié, 30-04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (TAPAH) WARNING NR
11//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 06W (TAPAH), LOCATED APPROXIMATELY 491 NM
SOUTHEAST OF IWO TO, JAPAN, HAS TRACKED NORTHWARD AT 07 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
SHOWS THE SYSTEM CONTINUES TO ELONGATE ALONG THE NORTHEAST QUADRANT
DUE TO HIGH VERTICAL WIND SHEAR (GREATER THAN 30 KNOTS). THE MSI
LOOP ALSO SHOWS THE CENTRAL CONVECTION REMAINS INTACT AND TIGHTLY
WRAPPED. THE INITIAL POSITION IS BASED ON THE 292329Z ASCAT PASS
OUTLINING A SYMMETRIC CIRCULATION WITH FAIR CONFIDENCE. THE INITIAL
INTENSITY IS SUPPORTED BY DVORAK ESTIMATES FROM PGTW, RJTD, AND KNES
AND REFLECTS THE WEAKENING TREND. UPPER LEVEL ANALYSIS INDICATES TS
06W IS 05 DEGREES NORTH OF THE RIDGE AXIS AND EMBEDDED IN THE STRONG
MID-LATITUDE WESTERLIES. HOWEVER, A STEADY POLEWARD OUTFLOW -
EVIDENT ON ANIMATED WATER VAPOR IMAGERY - CONTINUES TO PROVIDE
VENTILATION TO THE ASSOCIATED CONVECTION.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS TAPAH IS EXPECTED TO REMAIN ON TRACK ALONG THE WESTERN EDGE
OF A MID-LAYERED SUB-TROPICAL RIDGE (STR) TO THE EAST. AFTER TAU 12,
THE SYSTEM IS EXPECTED TO TRACK NORTH-NORTHWESTWARD IN ANTICIPATION
OF THE STR SLIGHTLY BUILDING. AFTERWARDS, SIGNIFICANTLY INCREASING
VERTICAL WIND SHEAR AND COOLING SEA SURFACE TEMPERATURES, IN
ADDITION TO ABSORPTION INTO THE COLD BAROCLINIC ZONE WILL RAPIDLY
ERODE THE SYSTEM, LEADING TO DISSIPATION BY TAU 48; POSSIBLY SOONER.
THE DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT AND LENDS HIGH
CONFIDENCE TO THE JTWC TRACK FORECAST WHICH IS LINED TO THE RIGHT OF
THE MULTI-MODEL CONSENSUS TO OFFSET AN EXAGGERATED WESTWARD TRACK
DEPICTED BY JGSM, JENS, AND AEMN.//
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