WDPN31 PGTW 180900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 02W (SURIGAE) WARNING 
NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON 02W (SURIGAE), LOCATED APPROXIMATELY 367 NM EAST OF 
MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 06 KNOTS OVER 
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE 
IMAGERY SHOWS SIGNIFICANTLY WARMED CONVECTIVE TOPS OVER AN ENLARGED 
CENTRAL DENSE OVERCAST AND UNRAVELING OF FEEDER BANDS. THE EYE, 
APPROXIMATELY 10NM IN DIAMETER, HAS BECOME PARTIALLY FILLED BUT 
REMAINS DISCERNIBLE AND LENDS HIGH CONFIDENCE IN THE INITIAL 
POSITION. IT APPEARS THAT EYEWALL REPLACEMENT HAS COMPLETED AS 
EVIDENCED BY THE DISAPPEARANCE OF THE MOAT FEATURE IN THE 180515Z 
AMSR2 89GHZ IMAGE. A MICROWAVE EYE IS ALSO EVIDENT IN THE AMSR2 
IMAGE AND LINED UP PERFECTLY WITH THE EIR EYE. THE INITIAL INTENSITY 
OF 135KTS IS BASED ON THE HIGHER END OF WEAKENING AGENCY DVORAK 
FINAL-T ESTIMATES FROM PGTW, RJTD, AND KNES OF T6.5/127KTS; AND THE 
OBJECTIVE ESTIMATE OF T6.6/130KTS FROM ADT. ANALYSIS INDICATES THE 
ENVIRONMENT HAS BECOME LESS FAVORABLE WITH THE LOW (5-10KT) VERTICAL 
WIND SHEAR (VWS) AND WARM (29-30C) SEA SURFACE TEMPERATURES (SSTS) 
IN THE PHILIPPINE SEA OFFSET BY DIMINISHING POLEWARD OUTFLOW THAT IS 
SUPPRESSED BY THE MIDLATITUDE TROUGH TO THE NORTH. THE CYCLONE IS 
TRACKING ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) 
TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. STY 02W WILL TRACK MORE TO THE NORTH-NORTHWEST AS THE STR 
ELONGATES MERIDIONALLY. THE DIMINISHING OUTFLOW OFFSETTING THE LOW 
VWS AND WARM SSTS WILL PRIMARILY BE RESPONSIBLE FOR ITS GRADUAL 
WEAKENING, DOWN TO 95KTS BY TAU 72. NUMERICAL MODELS ARE IN GOOD 
AGREEMENT WITH A GRADUAL AND EVEN CROSS-TRACK SPREAD TO 176NM BY TAU 
72, LENDING FAIR CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST 
TRACK, WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS.
   C. AFTER TAU 72, STY SURIGAE WILL CREST THE STR AXIS AND BEGIN 
ITS RECURVE ON THE POLEWARD SIDE, ACCELERATING NORTHEASTWARD. 
INCREASING VWS WILL CONTRIBUTE TO A MORE RAPID DECAY, DOWN TO 75KTS 
BY TAU 120. THE NUMERICAL MODELS CLUSTER CLOSER TO 130NM AT TAU 120, 
LENDING ALSO FAIR CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC 
TRACK FORECAST.//
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