MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 01W (ONE), LOCATED APPROXIMATELY 531 NM EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THAT OVER THE PAST FEW HOURS, FLARING CONVECTION WITH OVERSHOOTING TOPS HAS DEVELOPED NEAR THE ASSESSED LLCC, WITH SOMEWHAT SHALLOWER CONVECTIVE BANDS EXPANDING ACROSS THE SOUTHERN HEMISPHERE OF THE CIRCULATION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON EXTRAPOLATION OF A 2225Z DMSP COLOR 37 GHZ MICROWAVE IMAGE AND A 2356Z ASCAT-B SCATTEROMETER BULLSEYE PASS. THE INITIAL INTENSITY OF 30 KNOTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T1.5 (25-30KTS) FROM BOTH PGTW AND RJTD, HEDGED SLIGHTLY HIGHER IN LIGHT OF AN ADVANCED DVORAK TECHNIQUE ESTIMATE OF T2.0 (30 KNOTS) AND THE AFOREMENTIONED ASCAT PASS INDICATING 30 KNOT WINDS IN THE SOUTHEAST QUADRANT. ENVIRONMENTAL ANALYSIS REVEALS THAT TD 01W LIES IN A FAVORABLE ENVIRONMENT WITH LOW (10-15KT) VWS, MODERATE RADIAL OUTFLOW, BIASED TO THE EQUATORWARD SIDE PROVIDED BY A WEAK POINT SOURCE 429244OVER THE SYSTEM AND WARM (28-29C) SEA SURFACE TEMPERATURES (SSTS). THE CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) CENTERED OVER THE NORTHERN MARIANAS ISLANDS WITH A NORTH-SOUTH ORIENTED AXIS ALONG ROUGHLY 145E LONGITUDE. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE LAST PROGNOSTIC REASONING MESSAGE. B. OVER THE NEXT 12 HOURS TD 01W WILL TRACK GENERALLY NORTH TO NORTHWESTWARD ALONG THE WESTERN EDGE OF THE DEEP-LAYER STR CURRENTLY CENTER NORTH OF GUAM. AFTER THIS POINT THE STR BEGINS TO REORIENT ONTO A GENERALLY EAST-WEST ORIENTATION WHILST RE-CENTERING NEAR 20N 130E. THIS MOVEMENT WILL RESULT IN TD 01W MOVING ONTO A MORE WESTERLY TRACK TOWARDS THE CENTRAL PHILIPPINES THROUGH TAU 72. THE SYSTEM IS FORECAST TO SKIRT THE NORTHERN COAST OF SAMAR AND MAKE LANDFALL ON THE EXTREME SOUTHEASTERN COAST OF LUZON BY AROUND TAU 60. THE ENVIRONMENT IS EXPECTED TO REMAIN FAVORABLE THROUGH TAU 72, WITH THE UPPER LEVEL POINT SOURCE REMAINING OVERHEAD THE LLCC PROVIDING STRONG RADIAL OUTFLOW AND LOW VWS. FLOW OUT OF A TROPICAL UPPER-TROPOSPHERIC TROUGH (TUTT) CELL LOCATED IN THE SOUTH CHINA IS CURRENTLY IMPINGING ON THE OUTFLOW TO THE NORTHWEST OF THE SYSTEM. HOWEVER, THIS TUTT CELL IS FORECAST TO WEAKEN AND MOVE SOUTH, DECREASING THE PRESSURE ON THE NORTHWEST SIDE AND ALLOWING FOR INCREASED POLEWARD OUTFLOW, PROVIDING FUEL FOR A PERIOD OF RAPID INTENSIFICATION BETWEEN TAU 24 AND TAU 48. THE PEAK INTENSITY OF 70 KNOTS IS FORECAST TO OCCUR AT TAU 72. THE ACTUAL PEAK WILL LIKELY OCCUR AROUND TAU 60 WHILE THE SYSTEM IS STILL OVER WATER AND BE CLOSER TO 75 KNOTS. C. AFTER LANDFALL AROUND TAU 60, TD 01W IS FORECAST TO TRACK NORTHWESTWARD THEN NORTHWARD UNDER THE STEERING INFLUENCE OF THE STR AS IT MOVES EAST-SOUTHEAST. AFTER MAKING A SECOND LANDFALL ALONG THE EAST COAST OF NORTHERN LUZON, TD 01W WILL MOVE NORTH AND AGAIN EMERGE OVER WATER IN THE BASHI CHANNEL BY TAU 120. AFTER THE INITIAL LANDFALL AND TRANSIT OVER LAND, THE SYSTEM WILL WEAKEN SIGNIFICANTLY, BUT STRONG POLEWARD OUTFLOW INTO DEEP WESTERLY FLOW TO THE NORTH WILL ALLOW TD 01W TO MAINTAIN WEAK TROPICAL STORM STRENGTH EVEN WHILE OVER LAND. NUMERICAL MODEL GUIDANCE HAS COME INTO MUCH BETTER AGREEMENT SINCE THE PREVIOUS RUN, WITH ALL AVAILABLE MODELS IN STRONG AGREEMENT (<70NM SPREAD) THROUGH TAU 72. SIGNIFICANT DIVERGENCE IN MODEL SOLUTIONS DEVELOPS BEYOND TAU 96, WITH SPREAD BETWEEN OUTLIERS INCREASING TO 320 NM BY TAU 120, AS THE EXACT NATURE OF THE REORIENTATION AND MOVEMENT OF THE STR VARIES BETWEEN MODEL SOLUTIONS. THE JTWC FORECAST TRACK CONTINUES TO LIE JUST NORTH OF THE MULTI-MODEL CONSENSUS, AMONGST THE TIGHTEST PACKING OF AVAILABLE TRACKERS. WITH THE IMPROVED AGREEMENT IN THE GUIDANCE, THERE IS INCREASING CONFIDENCE IN THE JTWC FORECAST BUT CONFIDENCE IS STILL LOW DUE TO THE STILL DEVELOPING NATURE OF THE SYSTEM.// NNNN NNNN