WDPN32 PGTW 040300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (FIVE) WARNING NR 05// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 05W (FIVE), LOCATED APPROXIMATELY 89 NM NORTHEAST OF CHUUK, FSM, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS SLIGHTLY CONSOLIDATED AS CONVECTIVE BANDS WRAPPED TIGHTER INTO THE LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS BASED ON THE MSI LOOP AND ON A LLCC FEATURE IN THE 2156Z 36GHZ GPM SATELLITE PASS WITH FAIR CONFIDENCE. THE INITIAL INTENSITY OF 35 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD. UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY-FAVORABLE ENVIRONMENT WITH 10 TO 20 KNOT VERTICAL WIND SHEAR (VWS) OFFSET BY GOOD POLEWARD OUTFLOW. TS 05W IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A WEAK EXTENSION OF THE SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 05W WILL CONTINUE TRACKING UNDER THE STEERING INFLUENCE OF THE STR OVER THE NEXT 36 HOURS. AFTERWARDS, A MID-LATITUDE SHORTWAVE TROUGH DIGGING IN FROM THE NORTHEAST WILL WEAKEN THE STEERING STR AND CAUSE A PERIOD OF QUASI-STATIONARY MOTION BEFORE A NEAR EQUATORIAL RIDGE (NER) TO THE SOUTHEAST WILL ASSUME STEERING BY TAU 48. TS 05W MAY INTENSIFY TO A PEAK OF 45 KNOTS MAINLY DUE TO THE GOOD OUTFLOW. HOWEVER, AFTER THE NER ASSUMES STEERING AND NUDGES THE SYSTEM POLEWARD, THE VWS WILL INCREASE AND ERODE THE SYSTEM TO ITS DISSIPATION. THERE IS HIGH UNCERTAINTY IN THE STEERING PATTERN AS REFLECTED IN THE WIDE SPREAD IN THE MODEL GUIDANCE; THEREFORE, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.// NNNN