WDPN31 PGTW 311500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 29W (KROSA) WARNING NR 11//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 29W (KROSA), LOCATED APPROXIMATELY 227 NM NORTH-NORTHEAST 
OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY (IR) 
INDICATES TY 29W HAS INTENSIFIED AS IT MADE LANDFALL ACROSS 
NORTHEASTERN LUZON, DEVELOPING A 25NM EYE AND A SYMMETRIC RING OF 
DEEP CONVECTION AS SEEN IN A 310924Z SSMIS MICROWAVE IMAGE. THE 
INITIAL POSITION IS BASED UPON THE EYE FEATURE SEEN IN THE IR 
ANIMATION WITH GOOD CONFIDENCE. THE INITIAL INTENSITY HAS BEEN 
INCREASED TO 90 KNOTS BASED ON DVORAK INTENSITY ESTIMATES OF THE 
SAME VALUE FROM BOTH KNES AND PGTW AND THE INCREASING STRUCTURE. 
UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH NEAR-
RADIAL OUTFLOW AND LOW (05-10 KNOTS) VERTICAL WIND SHEAR (VWS). TY 
29W IS TRACKING WESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE 
SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST OF THE SYSTEM.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TY 29W IS FORECAST TO CONTINUE TO TRACK WEST-NORTHWESTWARD 
ALONG THE SOUTHWESTERN PERIPHERY OF THE CURRENT STEERING STR THROUGH 
TAU 36 AS THE SYSTEM SLIGHTLY WEAKENS IN THE NEAR TERM DUE TO THE 
PASSAGE ALONG THE NORTHERN LUZON COAST. AFTER WHICH, TY 29W WILL 
BEGIN TO RE-INTENSIFY AS IT MOVES INTO THE MORE OPEN WATERS OF THE 
SOUTH CHINA SEA. AFTER TAU 36, TY 29W IS EXPECTED TO SLOW AS IT 
SWITCHES FROM ITS CURRENT STR TO ANOTHER STR OVER SOUTHERN CHINA. 
THE STR OVER CHINA WILL BE THE DOMINATE STEERING FACTOR THROUGHOUT 
THE REST OF THE FORECAST AS IT BEGINS TO TRACK THE SYSTEM TO THE 
SOUTHWEST. AFTER TAU 48, A SLOW WEAKENING TREND IS EXPECTED AS LAND 
INTERACTION WITH HAINAN ISLAND, COOLER SSTS, AND INCREASING VERTICAL 
WIND SHEAR WILL BEGIN TO ERODE THE SYSTEM.
   C. IN THE EXTENDED TAUS, TY 29W WILL CONTINUE SOUTHWESTWARD UNDER 
THE STEERING INFLUENCE OF THE STR OVER SOUTHERN CHINA. CONTINUED 
WEAKENING IS EXPECTED AS ENVIRONMENTAL CONDITIONS CONTINUE TO BECOME 
FURTHER UNFAVORABLE AS THE SYSTEM MAKES LANDFALL INTO VIETNAM. AFTER 
LANDFALL, THE SYSTEM WILL DISSIPATE AS THE FRICTIONAL EFFECTS OF THE 
LAND DEGRADE THE SYSTEM. DYNAMIC GUIDANCE IS IN GOOD AGREEMENT 
THROUGH TAU 48; HOWEVER, THERE CONTINUES TO BE A LARGE SPREAD IN 
SOLUTIONS AS THE SYSTEM SWITCHES STEERING INFLUENCES FROM ITS 
CURRENT STR TO THE STR OVER CHINA. DUE TO THIS, LOW OVERALL 
CONFIDENCE REMAINS IN THE FORECAST TRACK WHICH IS POSITIONED CLOSE 
TO MULTI-MODEL CONSENSUS.//
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