Tropical Storm KUJIRA Advisory Tue Sep 29

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 15W (KUJIRA) WARNING NR
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 15W (KUJIRA), LOCATED APPROXIMATELY 734 NM EAST
OF YOKOSUKA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 23 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS
STRONG POLEWARD OUTFLOW CONTINUED TO ENHANCE AND DEEPEN THE CENTRAL
CONVECTION THAT IS NOW VERY CLOSE TO FORMING AN EYE. THE INITIAL
POSITION AND INTENSITY ARE EXTRAPOLATED WITH HIGH CONFIDENCE FROM A
DEFINED CIRCULATION IN THE 282328Z ASCAT BULLSEYE PASS AND CLUSTERED
DVORAK FIXES OF T3.5/55KTS FROM PGTW AND T4.0/65KTS FROM RJTD. ANALYSIS
INDICATES A MARGINALLY-FAVORABLE ENVIRONMENT WITH ROBUST POLEWARD
OUTFLOW AND WARM SST (29-30C) THAT ARE PARTLY OFFSET BY LOW TO MODERATE
(10-20KT) VERTICAL WIND SHEAR (VWS). ALSO, STRONG CONVERGENCE OVER THE
SOUTHERN SEMICIRCLE ASSOCIATED WITH AN UPPER LEVEL TROUGH CONTINUES TO
TEMPER CONVECTIVE DEVELOPMENT. TS 15W IS TRACKING UNDER THE STEERING
INFLUENCE OF A SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS KUJIRA WILL CONTINUE TO ACCELERATE NORTHEASTWARD ON THE
POLEWARD SIDE OF THE STR. THE MARGINALLY-FAVORABLE ENVIRONMENT WILL
PROMOTE FURTHER INTENSIFICATION TO A PEAK OF 65KTS BY TAU 12.
AFTERWARD, INCREASING VWS AND COOLING SSTS WILL GRADUALLY WEAKEN THE
SYSTEM TO 45KTS BY TAU 36. CONCURRENTLY BY TAU 12, TS 15W WILL BEGIN
EXTRATROPICAL TRANSITION AS IT ENTERS THE BAROCLINIC ZONE, BECOMING A
STORM-FORCE COLD CORE LOW BY TAU 24. NUMERICAL MODELS REMAIN IN TIGHT
AGREEMENT THROUGHOUT THE FORECAST PERIOD, LENDING HIGH CONFIDENCE IN
THE JTWC FORECAST TRACK.//
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