Tropical Storm CHAN-HOM Advisory Sun Oct 11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (CHAN-HOM) WARNING
NR 026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 16W (CHAN-HOM), LOCATED APPROXIMATELY 190 NM
SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED EASTWARD AT 09 KNOTS
(KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) REVEALS A PARTIALLY-EXPOSED, DEFINED LOW LEVEL
CIRCULATION CENTER (LLCC) WITH DEEP FLARING CONVECTION DISPLACED TO
THE NORTHEAST. A 102225Z GMI 89 GHZ MICROWAVE IMAGE DEPICTS A BROAD
LLCC WITH FRAGMENTED REGIONS OF FLARING CONVECTION TO THE NORTHEAST.
BASED ON THE MSI AND MICROWAVE IMAGERY, THERE IS GOOD CONFIDENCE IN
THE INITIAL POSITION. DVORAK CURRENT INTENSITY ESTIMATES OF T2.5-3.5
(35-45 KTS) BY PGTW AND RJTD SUPPORT THE INITIAL INTENSITY OF 40
KTS. FURTHERMORE, A 102304Z ASCAT-A IMAGE SHOWS A LARGE SWATH OF 35-
40 KT WINDS IN THE NORTHWEST QUADRANT, LENDING GOOD CONFIDENCE TO
THE INITIAL INTENSITY. STRONG VERTICAL WIND SHEAR (VWS) AND
CONTINUED DRY AIR ENTRAINMENT CONTRIBUTE TO AN OVERALL MARGINAL
ENVIRONMENT. TS 16W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE
BAROCLINIC ZONE AND THUS EXPERIENCING BAROCLINIC INFLUENCES WITHIN
THE ZONAL SUBTROPICAL WESTERLY FLOW. BROAD LOW-LEVEL SUBTROPICAL
RIDGES (STR) ENTRENCHED TO THE EAST AND SOUTHWEST OF THE SYSTEM ARE
ALSO INFLUENCING THE STEERING ENVIRONMENT.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 16W IS EXPECTED TO TURN SOUTHEASTWARD AS IT TRANSITS ALONG
THE EASTERN PERIPHERY OF THE LOW-LEVEL STR LOCATED TO THE SOUTHWEST.
AFTERWARDS, THE SYSTEM WILL CONTINUE SOUTHWARD FOR THE DURATION OF
THE FORECAST PERIOD. TS 16W WILL WEAKEN THROUGHOUT THE PERIOD DUE TO
HIGH (>30 KT) VWS AND CONTINUED DRY AIR ENTRAINMENT WITH DISSIPATION
ANTICIPATED BY TAU 48. THE STR TO THE EAST, ALTHOUGH FORECAST TO
WEAKEN, SHOULD LIMIT EASTWARD PROGRESSION. NUMERICAL MODEL GUIDANCE,
WITH THE EXCEPTION OF THE JGSM SOLUTION, HAS COME INTO BETTER
AGREEMENT AND THEN DIVERGES AFTER TAU 36 WITH A 50 NM SPREAD BY TAU
48. DUE TO THIS SPREAD, THERE IS FAIR CONFIDENCE IN THE JTWC
FORECAST TRACK.//
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