Tropical Storm MAYSAK Advisory Sun Apr 05

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (MAYSAK) WARNING NR
39//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 04W (MAYSAK), LOCATED APPROXIMATELY 188 NM
NORTH OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ENHANCED IR SATELLITE IMAGERY REVEALS THAT
THE BULK OF THE DEEP CONVECTION ASSOCIATED WITH THIS SYSTEM REMAINS
OVER CENTRAL LUZON. ADDITIONALLY, AN INDUCED BROAD LOW LEVEL CYCLONE
HAS BEGUN TO FORM OFF THE WESTERN COAST OF VIGAN. A 051049Z SSMIS
ALSO REVEALS THIS BROAD INDUCED FEATURE. DUE TO THE SYSTEM BEING
OVER LAND AND THIS INDUCED CYCLONIC FLOW. THE INITIAL POSITION AND
INTENSITY ARE MADE WITH LOW CONFIDENCE DUE TO LIMITED OBSERVATIONS
AVAILABLE. UPPER-LEVEL ANALYSIS IS MARGINAL AS THE SYSTEM REMAINS IN
AN AREA OF MODERATE (15 TO 20 KNOT) NORTHWESTERLY VERTICAL WIND
SHEAR (VWS) AND WEAK RADIAL OUTFLOW. THE CYCLONE IS TRACKING ALONG
THE SOUTHWESTERN PERIPHERY OF THE DEEP LAYERED SUBTROPICAL RIDGE
(STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. AS TS MAYSAK CONTINUES TO TRACK INTO THE SOUTH CHINA SEA
(SCS), EXPECT FURTHER DEGRADATION DUE TO THE INCREASED VWS
THROUGHOUT THE FORECAST PERIOD. WHILE THE AFOREMENTIONED STR WILL BE
THE PRIMARY STEERING FACTOR, BEYOND TAU 36 A NORTHEASTERLY SURGE
WILL CONTINUE TO WEAKEN THE SYSTEM AS WELL AS DRIVE IT TO THE WEST
BEFORE COMPLETE DISSIPATION AND EQUATORWARD FALL OF THE SYSTEM BY
TAU 72. NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, LEADING
TO HIGH CONFIDENCE IN THE JTWC FORECAST.//
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