Tropical Storm HAISHEN Advisory sam, 04.04.

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.//
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