WDPN31 PGTW 111500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W
/WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL STORM (TS) 03W, AERE, LOCATED APPROXIMATELY 325 NM
SOUTH OF SASEBO, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 20 KNOTS
DURING  THE PAST SIX HOURS. THE PEAK WIND REPORTED AT KADENA AIR BASE
DURING PASSAGE WAS 37 KNOTS. THE CURRENT INTENSITY ASSESSMENT IS
BASED ON WIND AND PRESSURE REPORTS FROM NORTHERN RYUKU REPORTING
STATIONS, PARTICULARLY RJKA. SUBJECTIVE DVORAK ESTIMATES ARE
UNREPRESENTATIVE DUE TO THE DIMINISHED CONVECTION OVER THE SYSTEM
CORE. AN 110509Z AMSRE IMAGE CONFIRMS THAT 03W REMAINED ORGANIZED IN
THE LOWER LEVELS WHILE TRACKING ALONG THE WEST COAST OF OKINAWA, AND
AN 111137Z SSMIS IMAGE SHOWS LITTLE REDUCTION IN ORGANIZATION. TC 03W
IS STEERING OVER THE TOP OF THE SUB-TROPICAL RIDGE AND ENTERING THE
INITIAL STAGE OF EXTRA-TROPICAL TRANSITION (XTT). ANIMATED INFRARED
SATELLITE IMAGERY SHOWS CLOUD TOPS WARMING AND THE CLOUD SHIELD
STRETCHING. THE EFFECTS OF INCREASING VERTICAL WIND SHEAR (VWS) ARE
EVIDENT IN BOTH INFRARED AND WATER VAPOR ANIMATION. WHILE THE UPPER
LEVELS OF THE STORM ARE SHOWING THE FIRST INDICATIONS OF COUPLING
WITH THE MID-LATITUDE WESTERLIES, TOTAL PRECIPITABLE WATER LOOPS SHOW
THAT THE LOWER LEVELS ARE STILL ENSCONCED WITHIN THE TROPICAL AIR.
THE BAROCLINIC ZONE IS PUSHING SLOWLY EQUATORWARD AND NOW EXTENDS
OVER KYUSHU, SHIKOKU, AND EASTERN HONSHU. TC 03W IS TRACKING OVER
UNFAVORABLY COOL SEA SURFACE TEMPERATURES AS IT APPROACHES THE BOUNDARY. 
3. FORECAST REASONING.
   A. NO SIGNIFICANT CHANGE TO FORECAST PHILOSOPHY.
   B. TC 03W WILL WEAKEN ONLY SLIGHTLY AS IT TRANSITIONS TO A
LOW-GALE FORCE EXTRA-TROPICAL LOW EAST OF HONSHU.  AS THE STORM
APPROACHES THE MID-LATITUDE WESTERLIES, THE ENHANCED OUTFLOW WILL
BALANCE THE EFFECTS OF INCREASING WIND  SHEAR FOR A SHORT TIME.  IN
THE BOUNDARY LEVELS, THE INCREASED THERMAL GRADIENT AS THE SYSTEM
INTERACTS WITH THE FRONTAL ZONE WILL COMPENSATE FOR THE COOLING SEA
SURFACE TEMPERATURES.  THE XTT WILL BE A SLOW PROCESS DUE TO THE
DISTANCE BETWEEN THE BAROCLINIC BOUNDARY AND 03W AND THE RELATIVELY
PARALLEL MOVEMENT BETWEEN THE TWO SYSTEMS.  RECENT MODEL GUIDANCE IS
IN EXCELLENT AGREEMENT WITH TRANSITIONING 03W INTO A LOW-GALE FORCE
MID-LATITUDE LOW AS IT TRACKS SEAWARD OF THE KANTO PLAIN.  DUE TO THE
GOOD AGREEMENT OF THE DYNAMIC MODELS AND THE PREDICTABLE BEHAVIOR OF
03W THUS FAR, THE JT FORECAST STAYS CLOSE TO CONSENSUS.
//
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