MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NANGKA) WARNING NR 38//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 11W (NANGKA), LOCATED APPROXIMATELY 931 NM SOUTH-
SOUTHEAST OF SASEBO, JAPAN, HAS TRACKED NORTHWESTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED IR IMAGERY SHOWS THE
SYSTEM HAS BECOME MORE SYMMETRICAL AS FEEDER BANDS HAVE RE-
CONSOLIDATED. THE INITIAL POSITION IS BASED ON A MICROWAVE EYE
FEATURE IN THE 121741Z 37GHZ GPM IMAGE. THE INITIAL INTENSITY OF 90
KNOTS IS BASED ON CONGRUENT DVORAK ESTIMATES FROM PGTW AND RJTD AND
REFLECTS THE IMPROVED BANDING. UPPER LEVEL ANALYSIS CONTINUES TO
SHOW HIGH NORTHERLY VWS OFFSET BY EXCELLENT RADIAL OUTFLOW, ENHANCED
BY A POINT SOURCE ALOFT. THE CYCLONE HAS BEGUN TO ROUND THE WESTERN
EDGE OF THE STEERING STR TO THE NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TY 11W IS FORECAST TO TRACK POLEWARD TOWARDS A BREAK IN THE
STEERING STR. AFTER TAU 48, THE STR IS EXPECTED TO STRENGTHEN AND
BUILD BACK IN, DEFLECTING THE SYSTEM NORTHWESTWARD TOWARDS THE
JAPANESE ISLAND OF SHIKOKU. THE VIGOROUS OUTFLOW WILL CONTINUE TO
OFFSET THE HIGH VWS RESULTING IN GRADUAL INTENSIFICATION OVER THE
NEXT 72 HOURS PEAKING AT 110 KNOTS.
C. AFTER TAU 72, TY NANGKA WILL CONTINUE TO TRACK TO THE NORTHWEST
UNDER THE INFLUENCE OF THE AFOREMENTIONED STR, MAKING LANDFALL OVER
SHIKOKU SHORTLY AFTER TAU 96. INCREASING VWS, IN ADDITION TO LAND
INTERACTION, WILL BEGIN TO WEAKEN THE SYSTEM AT THE EXTENDED PORTION
OF THE FORECAST. DYNAMIC MODEL GUIDANCE HAS COME INTO BETTER
AGREEMENT DIRECTIONALLY, HOWEVER, THERE IS A DISTINCT DISCREPANCY IN
THE TRACK SPEEDS, LENDING AN OVERALL LOW CONFIDENCE IN THE JTWC
FORECAST TRACK.//
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