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 NORTHWEASTWARD. 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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