Tropical Storm IN-FA Advisory чт, 19.11.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (IN-FA)
WARNING NR 08//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 27W (IN-FA), LOCATED APPROXIMATELY 128 NM
EAST-SOUTHEAST OF CHUUK, FSM, HAS TRACKED WEST-NORTHWESTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS THE SYSTEM HAS SLIGHTLY WEAKENED OVER THE
PAST SIX HOURS AS EVIDENCED BY FRAGMENTING CONVECTION WITH WARMING
TOPS ON THE EIR LOOP. THE INITIAL POSITION IS BASED ON THE EIR
ANIMATION AND SUPPORTED BY A 181618Z AMSU-B MICROWAVE PASS WITH GOOD
CONFIDENCE. THE INITIAL INTENSITY OF 55 KNOTS IS BASED ON AN OVERALL
ASSESSMENT OF DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD AND REFLECTS
THE WEAKENED STATE OF THE SYSTEM. UPPER LEVEL ANALYSIS INDICATES THE
CYCLONE IS IN AN AREA OF LIGHT (05-10 KNOT) VERTICAL WIND SHEAR (VWS)
AND GOOD NORTHEASTWARD AND EQUATORWARD OUTFLOW. HOWEVER, THERE IS
SUBSIDENCE OCCURRING ALONG THE NORTHWEST PERIPHERY, AS EVIDENT ON
ANIMATED WATER VAPOR IMAGERY. ALONG-TRACK SEA SURFACE TEMPERATURES
ARE AT 29-30 DEGREES CELSIUS. TS 27W IS TRACKING ALONG THE SOUTHERN
PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE PREVIOUS FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 27W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD AND WILL
GRADUALLY RE-INTENSIFY AS ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE,
REACHING 100 KNOTS BY TAU 72.
   C. BEYOND TAU 72, TS IN-FA WILL TRACK MORE POLEWARD AS A MINOR
MID-LATITUDE TROUGH CREATES A WEAKNESS IN THE STR AND THE SYSTEM WILL
BEGIN TO ROUND THE RIDGE AXIS. THE INITIAL EXPOSURE TO THE STRONG
MID-LATITUDE WESTERLIES WILL INITIALLY ENHANCE POLEWARD OUTFLOW AND
SUSTAIN THE PEAK INTENSITY UP TO TAU 96. AFTERWARDS, INCREASING VWS
WILL BEGIN TO ERODE THE SYSTEM. DYNAMIC MODEL GUIDANCE IS IN OVERALL
 GOOD AGREEMENT WITH SOME SPREADING AT THE END OF THE FORECAST TRACK.
IN VIEW OF THIS, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST
UP TO TAU 96 ONLY.//
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