Tropical Storm KROVANH Advisory dim, 20.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 20W (KROVANH) WARNING
NR 22//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 20W (KROVANH), LOCATED APPROXIMATELY 427 NM
EAST-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHEASTWARD AT 09
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION CENTER
(LLCC) WITH DECAYING DEEP CONVECTION DISPLACED OVER THE NORTHEAST
QUADRANT OF THE LLCC. THE 192202Z SSMIS 91GHZ AND 37GHZ IMAGE
INDICATE A SLIGHT TILT (ABOUT 30NM) TO THE NORTHEAST. THE CURRENT
POSITION IS BASED ON THE LOW-LEVEL CENTER AS INDICATED BY A
MICROWAVE EYE FEATURE IN THE 37GHZ IMAGE WITH GOOD CONFIDENCE. THE
INITIAL INTENSITY IS ASSESSED AT 55 KNOTS BASED ON AN AVERAGE OF
DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM 45 TO 65 KNOTS.
UPPER-LEVEL ANALYSIS INDICATES TS 20W IS LOCATED IN AN UNFAVORABLE
ENVIRONMENT WITH STRONG (30 TO 40 KNOTS) SOUTHWESTERLY VWS OFFSET BY
VIGOROUS POLEWARD OUTFLOW. TS 20W IS TRACKING ALONG THE NORTHWESTERN
PERIPHERY OF A DEEP-LAYERED STR.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 20W WILL REMAIN ON A NORTHEASTWARD TRAJECTORY THROUGH THE
REMAINDER OF THE FORECAST PERIOD. PERSISTENT STRONG VWS ASSOCIATED
WITH THE MIDLATITUDE WESTERLIES WILL SERVE TO WEAKEN THE SYSTEM AS
IT TRANSITIONS TO AN EXTRA-TROPICAL CYCLONE BY TAU 36. DYNAMIC MODEL
GUIDANCE REMAINS IN GOOD AGREEMENT, THEREFORE, THERE IS HIGH
CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS POSITIONED CLOSE TO
THE MULTI-MODEL CONSENSUS.//
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