WDPN33 PGTW 100300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 31W (HAIYAN) WARNING NR 28//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 31W (HAIYAN), LOCATED APPROXIMATELY 111 NM EAST OF
DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 17 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL IMAGERY INDICATES 
THAT THE SYSTEM HAS CONTINUED TO WEAKEN BUT HAS RETAINED TIGHTLY-
CURVED BANDING AND A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. A 
100055Z SSMIS 37GHZ IMAGE DEPICTS A SMALL MICROWAVE EYE FEATURE, 
WHICH SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. THE 
INITIAL INTENSITY OF 85 KNOTS IS HEDGED SLIGHTLY LOWER THAN THE 
DVORAK CURRENT INTENSITY ESTIMATES OF 90 KNOTS FROM PGTW, KNES AND 
RJTD. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM HAS MAINTAINED 
FAVORABLE OUTFLOW AND WEAK VERTICAL WIND SHEAR (VWS). TY 31W IS 
CURRENTLY TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE 
SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. AFTER TAU 12, TY 31W IS FORECAST TO TURN SHARPLY POLEWARD AS 
IT TRACKS ALONG THE WESTERN PERIPHERY OF THE STR. TY 31W IS FORECAST 
TO WEAKEN THROUGH THE REMAINDER OF THE FORECAST PERIOD AS IT 
ENCOUNTERS COOLER SST AND LAND INTERACTION. A MORE SIGNIFICANT 
WEAKENING PHASE WILL OCCUR AFTER TAU 24 AS THE SYSTEM MAKES LANDFALL 
OVER NORTHERN VIETNAM WITH DISSIPATION EXPECTED BETWEEN TAU 48 AND 
TAU 72. DUE TO THE RAPID WEAKENING EXPECTED AFTER TAU 24, THE 
AVAILABLE DYNAMIC GUIDANCE HAS DIVERGED BUT IS IN OVERALL FAIR 
AGREEMENT WITH THE BULK OF THE GUIDANCE INDICATING A RECURVATURE 
SCENARIO INTO NORTHERN VIETNAM. GFDN AND JGSM ARE THE PRIMARY 
OUTLIERS AND SHOW A MORE WESTWARD TRACK. THE JTWC FORECAST TRACK 
REMAINS CONSISTENT WITH THE PREVIOUS FORECASTS FAVORING THE MORE 
RELIABLE MODELS (ECMWF, GFS, NAVGEM, EGRR) SHOWING A RECURVE. THE 
JTWC FORECAST IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS 
THROUGH TAU 48 WITH HIGH CONFIDENCE.//
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