WDPN31 PGTW 191500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (LEEPI) 
WARNING NR 08//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 04W (LEEPI), LOCATED APPROXIMATELY 216 NM SOUTHWEST
OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTHWARD AT 09 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) SHOWS FRAGMENTED CONVECTIVE BANDS WRAPPING INTO A POORLY
DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS
BASED ON THE MSI LOOP AND A 191107Z SSMI/S MICROWAVE PASS WITH POOR
CONFIDENCE. THE INITIAL INTENSITY IS BASED ON CONGRUENT DVORAK
ESTIMATES FROM PGTW AND RJTD. UPPER-LEVEL ANALYSIS INDICATES
SUSTAINED FAVORABLE ENVIRONMENT WITH LIGHT TO MODERATE (10-20 KNOT)
VERTICAL WIND SHEAR (VWS) ENHANCED BY MODERATE RADIAL OUTFLOW.
ALONG-TRACK SEA SURFACE TEMPERATURES (SSTS) ARE ALSO FAVORABLE AT
28-30 DEGREES CELSIUS. TS 04W IS TRACKING ALONG THE WESTERN PERIPHERY
OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS LEEPI WILL CONTINUE TO TRACK POLEWARD OVER THE NEXT 12
HOURS. AFTERWARDS, IT WILL ROUND THE STR AND ACCELERATE NORTHEASTWARD
AS IT BECOMES EMBEDDED IN THE PREVAILING WESTERLIES. THE SYSTEM WILL 
EXPERIENCE SLIGHT INTENSIFICATION AS FAVORABLE VWS AND SSTS PERSIST.
PEAK INTENSIFICATION IS EXPECTED AT TAU 24-36 WITH INCREASED OUTFLOW
FROM INITIAL EXPOSURE TO THE STRONG WESTERLY WINDS. INCREASING VWS
AND DECREASING SSTS WILL LEAD TO THE DETERIORATION OF THE SYSTEM SOON
AFTER. AFTER TAU 48, TS 04W WILL FURTHER ACCELERATE INTO THE
MID-LATITUDES AND COMMENCE EXTRATROPICAL TRANSITION, BECOMING A
COLD-CORE LOW BY TAU 72. DYNAMIC MODEL GUIDANCE CONTINUES TO BE IN
TIGHT AGREEMENT WITH THE EXCEPTION OF NAVGEM AS THE SOLE LEFT
OUTLIER. THERE IS HIGH CONFIDENCE TO THE FORECAST TRACK WHICH IS 
LAID SLIGHTLY RIGHT OF MODEL CONSENSUS (CONW) AND THEN FASTER THAN
CONW AFTER TAU 36.   //
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