WDPN31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (WIPHA) WARNING NR 15//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 25W (WIPHA), LOCATED APPROXIMATELY 370 NM WEST-SOUTHWEST 
OF IWO TO, HAS TRACKED NORTH-NORTHWESTWARD AT 13 KNOTS OVER THE PAST 
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A 
LARGE SYSTEM WITH TIGHT SPIRAL BANDING WRAPPING INTO A LOW LEVEL 
CIRCULATION CENTER (LLCC) WITH AN EYE THAT HAS CONTRACTED AND BECOME 
MORE RAGGED OVER THE PAST SIX HOURS. A 132338Z SSMIS 91 GHZ 
MICROWAVE IMAGE REVEALS THE BREAKDOWN (ERC) OF INNER EYEWALL 
STRUCTURE AND LENDS EVIDENCE THAT AN EYEWALL REPLACEMENT CYCLE IS 
TAKING PLACE. THE CURRENT POSITION, INDICATING A SLIGHT SHIFT TO A 
NORTH-NORTHWESTERLY TRACK, IS BASED ON THE MSI, EYE FIXES FROM PGTW 
AND RJTD, AND THE AFOREMENTIONED SSMIS IMAGE WITH HIGH CONFIDENCE. 
THE CURRENT INTENSITY IS ASSESSED AT 110 KNOTS BASED ON DVORAK 
CURRENT INTENSITY ESTIMATES OF 115 KNOTS FROM PGTW AND RJTD, AND 
TAKING INTO ACCOUNT THE SLIGHT DEGRADATION OF THE STRUCTURE. CIMSS 
AMSU ESTIMATES ARE NOW AT 102 KNOTS. UPPER LEVEL ANALYSIS INDICATES 
FAVORABLE CONDITIONS REMAIN IN PLACE WITH AMPLE DUAL-CHANNEL OUTFLOW 
AND LOW TO MODERATE (10-15 KNOTS) VERTICAL WIND SHEAR (VWS). SSTS 
REMAIN FAVORABLE, AT 28-29 DEGREES CELSIUS. TY 25W IS TRACKING ALONG 
THE WESTERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO 
THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 25W WILL ROUND THE STR OVER THE NEXT 12-24 HOURS AND 
RECURVE TO THE NORTHEAST. OVER THE NEXT 12 HOURS, GENERALLY 
FAVORABLE ENVIRONMENTAL CONDITIONS INCLUDING INCREASED OUTFLOW INTO 
THE MID-LATITUDE WESTERLIES, MAY OFFSET THE EFFECTS OF THE ERC AND 
ALLOW TY 25W TO REMAIN NEAR ITS CURRENT INTENSITY. AFTER THAT TIME, 
INCREASING VWS ASSOCIATED WITH THE APPROACHING TROUGH WILL START TO 
WEAKEN THE SYSTEM. AT TAU 36, TY 25W WILL BEGIN AN EXTRATROPICAL 
TRANSITION (ETT) AS IT INTERACTS WITH A BAROCLINIC MID-LATITUDE 
TROUGH MOVING IN FROM THE WEST BRINGING INCREASINGLY HIGHER VWS. 
BY TAU 48, TY 25W WILL BE MOVING OVER MUCH COOLER WATERS, AIDING THE 
ETT PROCESS, WHICH IS FORECAST TO COMPLETE PRIOR TO TAU 72. DESPITE 
THIS TRANSITION, TY 25W WILL STILL MAINTAIN A LARGE RADIUS OF STRONG 
WINDS AS IT PASSES THE EAST COAST OF JAPAN. DETERMINISTIC AND 
ENSEMBLE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT ON THE TRACK, 
ALTHOUGH NAVGEM AND GFDN ARE SIGNIFICANTLY SLOWER THAN THE REST OF 
THE GUIDANCE. BASED ON THE OVERALL GOOD AGREEMENT, THE FORECAST 
TRACK IS LAID VERY CLOSE TO THE PRIOR JTWC FORECAST, AND SLIGHTLY 
INSIDE OF THE MULTI-MODEL CONSENSUS.
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