WDPN31 PGTW 311500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 04W (MAYSAK) WARNING NR 
19//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 04W (MAYSAK), LOCATED APPROXIMATELY 114 NM 
EAST-NORTHEAST OF YAP, HAS TRACKED WESTWARD AT 14 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM 
CONTINUES TO INTENSIFY AND DEEPEN WITH THE 17-NM EYE PREVALENT. A 
311231Z AMSU-B IMAGE SHOWS DEEP CONVECTION CLEARLY DEFINED AS 
WRAPPING INTO THE EYE. THE INTENSITY IS BASED ON THE DVORAK 
ESTIMATES FROM ALL AGENCIES. UPPER LEVEL ANALYSIS SHOWS THE SYSTEM 
IS IN AN AREA OF LOW (5 TO 10 KNOTS) VERTICAL WINDSHEAR (VWS) AND 
VERY GOOD POLEWARD OUTFLOW. STY MAYSAK IS TRACKING ALONG THE 
SOUTHERN PERIPHERY OF THE DEEP-LAYERED 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. STY 04W WILL CONTINUE TRACKING WEST-NORTHWESTWARD UNDER THE 
INFLUENCE OF THE STEERING STR THROUGHOUT THE FORECAST PERIOD. AS 
FAVORABLE ENVIRONMENTAL CONDITIONS CONTINUE, STY 04W WILL CONTINUE 
TO INCREASE IN INTENSITY OVER THE NEXT 24 HOURS. EXPECT A DECREASING 
TREND IN THE INTENSITY OF STY MAYSAK BEYOND TAU 24 AS VWS INCREASES 
AND THE SYSTEM TAKES A SLIGHTLY POLEWARD TURN AS STY MAYSAK 
APPROACHES A SMALL BREAK IN THE STR.
   C. IN THE EXTENDED FORECAST, STY 04W WILL CONTINUE TO WEAKEN AS 
IT ENCOUNTERS UPPER-LEVEL CONVERGENCE AND INCREASING VWS. THE SYSTEM 
WILL IMPACT CENTRAL LUZON BEYOND TAU 96. EXPECT A FURTHER RAPID 
DECREASE IN INTENSITY DUE TO LAND INTERACTION. DYNAMIC NUMERICAL 
MODEL GUIDANCE IS IN OVERALL TIGHT AGREEMENT, LENDING HIGH 
CONFIDENCE IN THE JTWC TRACK FORECAST WHICH IS LAID CLOSE TO THE 
MULTIMODEL CONSENSUS.//
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