WDPN31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (SURIGAE) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
    TROPICAL STORM 02W (SURIGAE), LOCATED APPROXIMATELY 65 NM SOUTH-
SOUTHWEST OF YAP, HAS TRACKED NORTH-NORTHWESTWARD AT 03 KNOTS OVER 
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A 
PARTIALY EXPOSED LOW LEVEL CIRCULATION CENTER, WITH THE DEEPEST 
CONVECTIVE BANDING BUILDING TO THE WEST AND NORTH OF THE CENTER. THE 
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 132343Z 
METOP-A ASCAT PASS SHOWING A CLEAR LLCC WITH EMBEDDED PATCHES OF 35 
KNOTS. THE INTENSITY OF 35 KNOTS IS BASED ON A PGTW DVORAK FIX OF 
T2.5 (35 KNOTS), ADVANCED DVORAK TECHNIQUE ESTIMATE OF 35 KNOTS AND 
THE AFOREMENTIONED ASCAT PASS. ANALYSIS INDICATES A FAVORABLE 
ENVIRONMENT WITH POLEWARD AND EQUATORWARD OUTFLOW CHANNELS, LOW (10-
20 KNOTS) VERTICAL WIND SHEAR, AND VERY WARM (29-30 DEGREES CELSIUS) 
SEA SURFACE TEMPERATURES IN THE PHILIPPINE SEA. THE CYCLONE IS 
TRACKING ALONG THE SOUTHWEST PERIPHERY OF A SUBTROPICAL RIDGE 
EXTENSION LOCATED TO THE NORTHEAST. 
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.   
   B. TS 02W WILL TRACK SLOWLY NORTHWARD THEN NORTHWESTWARD OVER THE 
NEXT 72 HOURS AS THE AFOREMENTIONED SUBTROPICAL RIDGE (STR) 
REORIENTS. THE AFOREMENTIONED FAVORABLE ENVIRONMENT WILL MAINTAIN 
AND PROMOTE STEADY INTENSIFICATION TO 85 KNOTS BY TAU 72. THERE IS A 
POSSIBILITY OF INDUCED PRESSURE THAT MAY DAMPEN CONVECTION TO THE 
EAST OF THE LLCC IN THE UPPER LEVELS. HOWEVER, IN TRACK GUIDANCE, 
NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT WITH A CROSS TRACK 
SPREAD OF 150NM BY TAU 72 WITH THE ENSEMBLE MEAN OF ECMWF MEMBERS 
TRACKING CLOSER TO THE PHILIPPINES AND JGSM SHOWING A MORE POLEWARD 
TRACK, WITH THE REMAINING MODELS FALLING BETWEEN THE TWO. GIVEN THE 
UNCERTAINTY IN THE INITIAL STORM MOTION, THERE IS FAIR CONFIDENCE IN 
THIS PORTION OF THE JTWC TRACK FORECAST.
   C. AFTER TAU 72, TS 02W WILL CONTINUE NORTHWESTWARD TOWARD THE 
BREAK IN THE RIDGE FORMED BY A MIDLATITUDE TROUGH DIGGING IN FROM 
EASTERN ASIA THAT WILL BREAK THE AFOREMENTIONED STR. AFTER THE STR 
BREAKS, TS 02W WILL TRACK ALONG THE WESTERN PERIPHERY OF THE STR 
FEATURE POSITIONED TO ITS EAST, DRIVING IT FURTHER NORTHWESTWARD 
UNTIL REACHING THE STR AXIS AROUND TAU 120. CONTINUED 
INTENSIFICATION IS EXPECTED AS THE FAVORABLE CONDITIONS ARE FURTHER 
ENHANCED BY INCREASED POLEWARD OUTFLOW. BY TAU 120, TS 02W IS 
EXPECTED TO REACH 115 KNOTS. NUMERICAL MODELS SPREAD OUT TO OVER 
300NM BY TAU 120, LENDING LOW CONFIDENCE TO THE EXTENDED PORTION OF 
THE JTWC TRACK FORECAST.//
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