Tropical Storm IN-FA Advisory Ter, 17-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (TWENTYSEVEN)
WARNING NR 02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 27W (TWENTYSEVEN), LOCATED APPROXIMATELY 264
NM SOUTHEAST OF POHNPEI, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS.  ANIMATED MSI DEPICTS A CONSOLIDATED LLCC WITH
DEEPENING CENTRAL CONVECTION, SPECIFICALLY ON THE SOUTHERN PORTION
OF THE SYSTEM. THE WATER VAPOR LOOP SHOWS THE SYSTEM HAS NEAR RADIAL
OUTFLOW AND A 170348Z N-19 IMAGE SHOWS GOOD CURVED CONVECTIVE
BANDING WRAPPING INTO A DEFINED LLCC. THE INITIAL POSITION IS BASED
ON THE AFOREMENTIONED SATELLITE IMAGERY WITH FAIR CONFIDENCE AND THE
INTENSITY HAS BEEN INCREASED TO 35 KNOTS BASED ON IMPROVED OVERALL
CONVECTION AND STRUCTURE AND SUPPORTED BY SATCON ESTIMATE OF 34
KNOTS. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS SOUTH OF THE STR
EXTENSION WITH GOOD DIFFLUENCE AND VERY LOW VWS.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE PREVIOUS FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 27W IS EXPECTED TO CONTINUE TRACKING TO THE NORTHWEST
THROUGHOUT THE FORECAST PERIOD AS IT WILL CONTINUE TO BE STEERED BY
THE STR EXTENSION. AS THIS EXTENSION DISSIPATES AND TRACKS TO THE
EAST SLIGHTLY, TS 27 WILL SLOWLY DEVELOP OVER THE NEXT 36 HOURS,
WITH ONLY MARGINAL INTENSIFICATION. BEYOND TAU 36, THE SYSTEM WILL
DEVELOP AT AN AVERAGE RATE AS THE UPPER LEVEL ENVIRONMENT BECOMES
MORE FAVORABLE, ALLOWING FOR AN INTENSITY OF 65 KNOTS BY TAU 72. AN
ALTERNATE FORECAST SCENARIO IS THAT THE SYSTEM WILL INCREASE AT A
MUCH FASTER RATE AS CURRENT ENVIRONMENTAL CONDITIONS ARE CONDUCIVE
FOR INTENSIFICATION. HOWEVER, MODELS DO NOT CURRENTLY REFLECT THAT
SCENARIO.
   C. IN THE EXTENDED FORECAST, THE SYSTEM WILL CONTINUE TO TRACK TO
THE NORTHWEST AS THE STR BUILDS TO THE EAST OF THE SYSTEM. CONTINUED
DEVELOPMENT IS EXPECTED WITH TS 27W REACHING 85 KNOTS BY THE END OF
THE FORECAST PERIOD. WHILE THERE IS LIMITED MODEL GUIDANCE, THE
TRACKS ARE IN FAIRLY GOOD AGREEMENT. HOWEVER, THERE REMAINS LOW
CONFIDENCE IN THE JTWC FORECAST DUE TO THE LACK OF MODELS
AVAILABLE.//
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