WDPN31 PGTW 132100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 02W (SURIGAE) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 02W (SURIGAE), LOCATED APPROXIMATELY 27 NM WEST-SOUTHWEST OF NGULU, HAS TRACKED NORTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM HAS FURTHER CONSOLIDATED WITH CONVECTION INCREASING OVERHEAD THE LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON 131910Z SSMIS 91GHZ MICROWAVE IMAGERY SHOWING BANDING WRAPPING AROUND THE LLCC FROM ITS WESTERN PERIPHERY. THE INTENSITY OF 30 KNOTS IS BASED ON A PGTW DVORAK FIX OF T2.0 (30 KNOTS) AND AN ADVANCED DVORAK TECHNIQUE ESTIMATE OF 29 KNOTS. 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. TD 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 75 KNOTS BY TAU 72. NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT WITH AN IMPROVED CROSS TRACK SPREAD OF 110NM BY TAU 72 WITH THE DETERMINISTIC ECMWF 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, TD 02W WILL CONTINUE NORTHWESTWARD TOWARD THE BREAK IN THE RIDGE FORMED BY A MIDLATITUDE TROUGH DIGGING IN FROM EASTERN ASIA. AFTER THE STR BREAKS, TD 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, TD 02W IS EXPECTED TO REACH 115 KNOTS. NUMERICAL MODELS SPREAD OUT EVEN MORE TO OVER 250NM BY TAU 120, LENDING LOW CONFIDENCE TO THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.// NNNN