Tropical Storm FAXAI Advisory Sat Sep 07

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FAXAI) WARNING NR
019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 14W (FAXAI), LOCATED APPROXIMATELY 479 NM
EAST OF IWO TO, HAS TRACKED NORTHWESTWARD AT 21 KNOTS (KTS) OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A
060454Z 85 GHZ MICROWAVE IMAGE DEPICT A LOW LEVEL CIRCULATION (LLC)
LOCATED UNDER FLARING DEEP CONVECTION, PROVIDING FAIR CONFIDENCE IN
THE INITIAL POSITION. THE INITIAL INTENSITY REMAINS AT 45 KTS BASED
ON DVORAK ESTIMATES OF T3.0/45 KTS FROM PGTW AND RJTD. UPPER-LEVEL
ANALYSIS REVEALS A WEAK TUTT CELL TO THE NORTHWEST AND TROUGHING TO
THE SOUTH OF TS 14W. THESE FEATURES CREATE SUBSIDENCE AND RESTRICTED
OUTFLOW ALONG THE WESTERN EDGE OF THE SYSTEM, LIMITING VERTICAL
DEVELOPMENT IN THAT REGION. THE WEAKENED TUTT CELL IS ALLOWING SOME
POLEWARD OUTFLOW TO DEVELOP TO ACCOMPANY THE SOUTHEASTWARD OUTFLOW.
TS 14W REMAINS IN A FAVORABLE VERTICAL WIND SHEAR (VWS) ENVIRONMENT
WITH VALUES OF 10-20 KTS AND CONTINUES TO TRACK OVER WARM (30
CELSIUS) SEA SURFACE TEMPERATURE (SST). A SUBTROPICAL RIDGE (STR) TO
THE NORTH IS PROVIDING THE PRIMARY STEERING INFLUENCE.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. BEFORE BEGINNING TO ROUND THE STR AXIS NEAR TAU 36, TS 14W
WILL MAINTAIN ITS CURRENT NORTHWESTWARD TRACK AROUND THE PERIPHERY
OF THE STR. AFTER TAU 48, TS 14W WILL MAKE A TURN TO THE NORTHEAST,
MAKING LANDFALL OVER HONSHU, JAPAN NEAR TOKYO SHORTLY AFTER
RECURVING. THE UPPER-LEVEL ENVIRONMENT WILL GRADUALLY BECOME MORE
FAVORABLE AS THE POLEWARD OUTFLOW CHANNEL BECOMES BETTER
ESTABLISHED, ALLOWING STEADY INTENSIFICATION TO A PEAK INTENSITY OF
80 KTS BY TAU 48. THE PREVAILING WESTERLIES WILL ENHANCE THIS
OUTFLOW AS WELL. AFTER LANDFALL, TS 14W WILL WEAKEN TO 65 KTS PRIOR
TO RE-EMERGING OVER THE PACIFIC OCEAN. WITH THE EXCEPTION OF NAVGEM
(EASTERN OUTLIER), DYNAMIC MODEL GUIDANCE IS IN EXCELLENT AGREEMENT
WITH THE JTWC TRACK FORECAST, LENDING HIGH CONFIDENCE TO THIS
PORTION OF THE FORECAST.
   C. AROUND TAU 72, TS 14W WILL BEGIN EXTRA-TROPICAL TRANSITION
(ETT) AND ACCELERATE NORTHEASTWARD. THE SYSTEM WILL CONTINUE TO
DECAY RAPIDLY DUE TO INCREASING VWS AND COOLING SST, TRANSFORMING
INTO A GALE-FORCE COLD CORE LOW WITH AN EXPANDING WIND FIELD BY TAU
96. NUMERICAL MODELS MAINTAIN GOOD ALONG-TRACK AND FAIR CROSS-TRACK
AGREEMENT FOR THIS PORTION OF THE FORECAST, LENDING FAIR CONFIDENCE
TO THE TRACK BEYOND TAU 72.//
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