WDPN31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TYPHOON (TY) 02W (SURIGAE), LOCATED APPROXIMATELY 42 NM NORTH OF 
KAYANGEL, PALAU HAS TRACKED WEST-SOUTHWESTWARD AT 06 KNOTS OVER THE 
PAST SIX HOURS. ANIMATED MULTI-SPECTRAL SATELLITE IMAGERY SHOWS 
TIGHTLY CURVED BANDING HAS NOW COMPLETELY WRAPPED AROUND THE 
OBSCURED LOW-LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION 
IS BASED IN A 160056Z METOP-B ASCAT PASS SHOWING A TIGHTLY WRAPPED 
CIRCULATION. THE INITIAL INTENSITY, WHICH HAS INCREASED TO 75 KNOTS, 
IS BASED ON THE DVORAK CURRENT INTENSITY ESTIMATES OF T4.5 (77 
KNOTS) BY PGTW, RJTD AND KNES AND AN ADVANCED DVORAK TECHNIQUE 
ESTIMATE OF 75 KNOTS. ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE 
ENVIRONMENT FOR FURTHER INTENSIFICATION WITH LOW (<15KT) VERTICAL 
WIND SHEAR (VWS), AND WARM (29-30C) SEA SURFACE TEMPERATURES (SST) 
IN THE PHILIPPINE SEA. TY 02W IS CURRENTLY TRACKING ALONG THE 
SOUTHERN PERIPHERY OF AN EXTENSION OF THE DEEP LAYER 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. TY 02W IS FORECAST TO TRACK NORTHWESTWARD AS A MIDLATITUDE 
TROUGH TO THE NORTHWEST DEEPENS AND BREAKS THE EXTENSION OF THE STR 
AROUND TAU 48, CAUSING TY 02W TO TURN NORTHWARD. THE SYSTEM WILL 
STEADILY INTENSIFY DUE TO ROBUST UPPER-LEVEL OUTFLOW CAUSED BY THE 
MIDLATITUDE TROUGH WITH TY 02W REACHING 115KTS BY TAU 48. NUMERICAL 
MODEL GUIDANCE REMAINS IN FAIR AGREEMENT WITH A CROSS-TRACK SPREAD 
OF 170NM AT TAU 72 WITH ECMWF AND ECMWF ENSEMBLE MEAN CONTINUING TO 
REMAIN FURTHER WEST OF THE REST OF THE MODELS. THE JTWC TRACK HAS 
BEEN PLACED NEAR THE MULTI-MODEL CONSENSUS WITH GOOD CONFIDENCE IN 
THE EARLY PORTION OF THE JTWC TRACK FORECAST.
   C. AFTER TAU 72, THE EASTERN PORTION OF THE BREAK IN THE STR 
TAKES OVER AS THE PRIMARY STEERING MECHANISM, CAUSING TY SURIGAE TO 
TRACK NORTHWARD THEN NORTH-NORTHEASTWARD AROUND THE WESTERN 
PERIPHERY OF THIS RIDGE. THE ENVIRONMENTAL CONDITIONS WILL BECOME 
SLIGHTLY LESS FAVORABLE AS THE AMOUNT OF UPPER-LEVEL DIVERGENCE 
DECREASES AND SEA SURFACE TEMPERATURES LOWER THROUGH THE END OF THE 
FORECAST PERIOD. THE SYSTEM WILL DECREASE DOWN TO 100KTS BY TAU 120. 
NUMERICAL MODEL CROSS-TRACK SPREAD IS 350NM AT TAU 120 AS TRACK 
SOLUTIONS DIVERGE FURTHER, LENDING LOW CONFIDENCE TO THE EXTENDED 
PORTION OF THE JTWC TRACK FORECAST.//
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