WDPN31 PGTW 181500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 021//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 02W (SURIGAE), LOCATED APPROXIMATELY 343 NM EAST
OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE 
IMAGERY SHOWS A SYSTEM THAT REMAINS INTENSE, ALBEIT WITH WARMING 
CONVECTIVE TOPS OVER A LARGE SYMMETRICAL CENTRAL DENSE OVERCAST THAT 
MAINTAINED A PINHOLE 12-NM EYE. THE INITIAL POSITION IS PLACED WITH 
HIGH CONFIDENCE BASED ON THE EYE FEATURE IN THE EIR LOOP. THE INITIAL 
INTENSITY OF 125KTS IS BASED ON THE HIGHER END OF WEAKENING AGENCY 
DVORAK FINAL-T ESTIMATES RANGING FROM T5.5/102KTS TO T6.5/127KTS; AND 
THE OBJECTIVE ESTIMATES OF T6.2/120KTS (ADT) AND 141KTS (SATCON). 
ANALYSIS INDICATES AN UNFAVORABLE ENVIRONMENT 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 ARE 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. TY 02W WILL TRACK MORE TO THE NORTH-NORTHWEST AS THE STEERING 
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 167NM 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, TY SURIGAE WILL CREST THE STR AXIS, RECURVE AND 
ACCELERATE NORTHEASTWARD. INCREASING VWS AND COOLING SSTS WILL 
CONTRIBUTE TO A MORE RAPID DECAY, DOWN TO 80KTS BY TAU 120. THE 
NUMERICAL MODELS REMAIN TIGHT AND SPREAD OUT TO 149NM AT TAU 120, 
LENDING ALSO FAIR CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK 
FORECAST.//
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