WDPN31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (TALIM) WARNING 
NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 20W (TALIM), LOCATED APPROXIMATELY 435 NM WEST-
NORTHWEST OF ANDERSEN AFB, GUAM, HAS TRACKED WEST-NORTHWESTWARD AT 11
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY SHOWS DEEP CENTRAL DENSE OVERCAST (CDO) FLARING CONVECTION
OBSCURING THE LOW LEVEL CIRCULATION (LLC). THE CDO FEATURE, FOR THE
MOST PART, HAS MAINTAINED DEPTH AND DEGREE OF WRAP INTO THE LLC. THE
INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON CURRENT
STORM MOTION AND ON A LOW REFLECTIVITY CIRCULATION FEATURE IN THE
101016Z AMSU-B MICROWAVE PASS. THE INITIAL INTENSITY REMAINS AT 40
KNOTS BASED ON AGENCY AND OBJECTIVE DVORAK ESTIMATES OF T2.5 TO T3.2. 
ENVIRONMENTAL ANALYSIS INDICATES THE SYSTEM IS IN A MARGINAL AREA 
FOR DEVELOPMENT WITH MODERATE (15-20 KNOT) VERTICAL WIND SHEAR 
AND MARGINAL OUTFLOW WITH A SINGLE EQUATORWARD CHANNEL THAT HAVE 
STIFLED DEVELOPMENT. TS 20W IS TRACKING UNDER THE INFLUENCE OF AN
EXTENSION OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE NORTH. 
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY 
FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 20W WILL CONTINUE TRACKING WEST-NORTHWESTWARD IN THE
PHILIPPINE SEA THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE
STR. THE AFOREMENTIONED MARGINAL CONDITIONS WILL PERSIST OVER THE
NEXT 24 HOURS, LIMITING INTENSIFICATION. HOWEVER, AFTER TAU 24, THE
STR IS EXPECTED TO RECEDE EASTWARD ALLOWING FOR AN IMPROVEMENT IN THE
OUTFLOW AND AID IN RAPID INTENSIFICATION TO A PEAK OF 105 KNOTS BY
TAU 72. MODEL GUIDANCE IS IN GOOD AGREEMENT, LENDING HIGH CONFIDENCE
TO THIS PORTION OF THE JTWC TRACK FORECAST. 
   C. BEYOND TAU 72, TS TALIM WILL TRACK ACROSS CENTRAL TAIWAN, THE
TAIWAN STRAIT AND MAKE A SECOND AND FINAL LANDFALL OVER SOUTHEASTERN
CHINA JUST BEFORE TAU 96. THE SYSTEM WILL THEN RECURVE NORTHWESTWARD
TOWARD A WEAKNESS IN THE STEERING STR. TS 20W WILL WEAKEN
SIGNIFICANTLY AFTER LANDFALL IN TAIWAN, BUT REMAIN A STRONG TYPHOON
AFTER REEMERGENCE INTO THE TAIWAN STRAIT. AFTER THE FINAL LANDFALL IN
CHINA, THE SYSTEM WILL RAPIDLY DECAY OVER LAND. DYNAMIC MODEL
GUIDANCE SIGNIFICANTLY SPREAD AFTER TAU 72, LENDING LOW CONFIDENCE IN
THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.//
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