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.// NNNN NNNN