WDPN31 PGTW 110300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (WUTIP) WARNING NR 003// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 16.2N 113.9E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 323 NM EAST OF DA NANG, VIETNAM MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 12 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A SMALL AND FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION BEGINNING TO FLARE UP ONCE MORE NEAR THE CENTER. ANIMATED WATER VAPOR IMAGERY, AS WELL AS CIRA TC-SCALE ATMOSPHERIC MOTION VECTORS INDICATE RELATIVELY STRONG NORTH-NORTHEASTERLY UPPER-LEVEL WINDS PUSHING SOUTH FROM AN ANTICYCLONE OVER THE TAIWAN STRAIT, IMPARTING MODERATE TO HIGH SHEAR OVER THE SYSTEM AT THE PRESENT TIME. A 120110Z ASCAT-B PASS INDICATED 25-30 KNOT WINDS AROUND THE MAJORITY OF THE CIRCULATION, WITH A RADIUS OF MAXIMUM WINDS AROUND 45NM. SHIP OBSERVATIONS INDICATE THE ELEVATED WINDS EXTEND OVER 150NM AWAY FROM THE CENTER, PRIMARILY FOCUSED IN THE EASTERN HEMISPHERE OF THE CIRCULATION. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE MSI. THE INITIAL INTENSITY IS ALSO ASSESSED WITH HIGH CONFIDENCE, BASED ON THE OVERALL AGREEMENT OF THE SUBJECTIVE AND OBJECTIVE FIXES WITH THE SCATTEROMETER DATA. ENVIRONMENTAL ANALYSIS REVEALS MARGINALLY FAVORABLE CONDITIONS, WITH STRONG EQUATORWARD OUTFLOW AND WARM SSTS OFFSET BY MODERATE NORTH-NORTHEASTERLY WIND SHEAR. AS DEPICTED WELL BY THE HAFS-A AND HWRF, A REGION OF RELATIVELY DRIER MID-LEVEL AIR REMAINS IN PLACE ACROSS THE NORTHERN PORTION OF THE CIRCULATION, BUT WEAK CONVECTION IN THE AREA SUGGESTS THE ATMOSPHERE IS MOISTENING. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) FAR TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS RJTD: T2.0 - 30 KTS KNES: T1.5 - 25 KTS CIMSS ADT: 33 KTS AT 110020Z CIMSS AIDT: 31 KTS AT 110020Z CIMSS DPRINT: 25 KTS AT 110000Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG EQUATORWARD OTHER FACTORS: DRY MID-LEVEL AIR ACROSS THE NORTHERN PERIPHERY OF THE CIRCULATION. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: AFTER COMPLETING A COUNTER-CLOCKWISE LOOP BETWEEN 12Z-18Z, TROPICAL DEPRESSION (TD) 01W (WUTIP) KICKED OUT TO THE NORTH, PUTTING THE PEDAL DOWN AND INCREASING SPEED FROM 02 KNOTS TO 11 KNOTS IN THE LAST SIX HOURS. THE MOST RECENT MOTION VECTOR LOOKS TO BE ABOUT 320DEG, HEADING TOWARDS HAINAN ISLAND. TD 01W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD THROUGH TAU 48, ALONG THE SOUTHWESTERN SIDE OF THE STEERING RIDGE. LANDFALL ALONG THE SOUTHEASTERN COAST OF HAINAN ISLAND IS EXPECTED SHORTLY AFTER TAU 36. THE MAJORITY OF THE TRACK GUIDANCE INDICATES THE SYSTEM SHOULD SLOW DOWN A BIT OVER THE NEXT 12 HOURS AS THE RIDGE IS EXPECTED TO WEAKEN AND BREAK DOWN A BIT DUE TO THE PRESENCE OF INVEST 94W IN THE PHILIPPINE SEA. HOWEVER, IF THE SYSTEM MAINTAINS ITS CURRENT SPEED, LANDFALL COULD OCCUR UP TO 6-12 HOURS EARLIER THAN CURRENTLY ANTICIPATED. THE CURRENT FORECAST SHOWS TD 01W ROUNDING THE RIDGE AXIS BY TAU 48 AS IT CROSSES OVER HAINAN ISLAND, THEN ACCELERATING NORTHEASTWARD THROUGH THE REMAINDER OF THE FORECAST PERIOD AS THE SYSTEM GETS CAUGHT UP IN THE ENHANCED GRADIENT FLOW AHEAD OF A MID-LATITUDE TROF MOVING IN FROM THE WEST. UPPER-LEVEL CONDITIONS ARE FORECAST TO IMPROVE, WITH SHEAR DECREASING AND OUTFLOW BECOMING MORE ORGANIZED, WHICH WILL ALLOW THE SYSTEM TO SYMMETRIZE AND THE VORTEX TO ALIGN VERTICALLY, ENABLING STEADY INTENSIFICATION THROUGH LANDFALL. WHILE THE PEAK OF 55 KNOTS IS SHOWN TO OCCUR AT TAU 36, THE SYSTEM MAY INTENSIFY AN ADDITIONAL 5-10 KNOTS IN THE PERIOD BETWEEN TAU 36 AND LANDFALL BUT CANNOT BE CAPTURED IN THE FORECAST TIME STEPS. AFTER MAKING LANDFALL, THE LOSS OF A OCEANIC HEAT SOURCE AND TERRAIN INTERACTION WILL STEADILY ERODE THE VORTEX, LEADING TO DISSIPATION BY TAU 96 TO THE NORTH OF HONG KONG. MODEL DISCUSSION: DETERMINISTIC GUIDANCE HAS COME INTO SLIGHTLY BETTER AGREEMENT SINCE THE LAST RUN, PARTICULARLY IN THE EXTENDED FORECAST. AT LANDFALL, CROSS-TRACK SPREAD IS 110NM, BETWEEN THE ECMWF-AIFS ON THE LEFT AND THE UKMET ON THE RIGHT SIDE OF THE ENVELOPE. CROSS-TRACK SPREAD INCREASES TO 200NM BY TAU 72 AND REMAINS STEADY THROUGH TAU 96. ALONG-TRACK SPREAD IS ABOUT 100NM AT LANDFALL BETWEEN THE ECMWF AND THE NAVGEM. MODELS CONTINUE TO SHOW ENHANCED ALONG-TRACK SPREAD DUE TO LARGE DISCREPANCIES IN HOW THEY ARE HANDLING THE STRENGTH OF THE MID-LATITUDE TROF MOVING IN FROM NORTH-CENTRAL CHINA. GFS IS STARTING TO MOVE INTO BETTER AGREEMENT TO THE FASTER MODELS, BUT STILL LAGS FAR BEHIND, WITH THE TROF BEING WEAKER, WHILE ECMWF AND THE UKMET SHOW A DEEPER TROF WHICH PICKS UP THE SYSTEM EARLIER. AFTER THE SYSTEM ROUNDS THE RIDGE AXIS, ALONG-TRACK INCREASES TO 460NM BY THE END OF THE FORECAST. THE JTWC FORECAST IS SITUATED TO THE WEST OF THE CONSENSUS MEAN AND CONSISTENT WITH THE ECWMF DETERMINISTIC MODEL THROUGH THE FORECAST PERIOD. INTENSITY GUIDANCE CONTINUES TO SHOW A FAIR AMOUNT OF UNCERTAINTY. SOMEWHAT SURPRISINGLY, THREE RAPID INTENSIFICATION (RI) AIDS ARE NOW BEING TRIPPED (CTR1, RIDE, RICN), AND THE COAMPS-TC (BOTH VERSIONS) ARE STICKING TO THEIR GUNS IN INDICATING A PEAK INTENSITY OF 65 KNOTS OR GREATER PRIOR TO LANDFALL. THE HAFS AND HWRF MEANWHILE HAVE COME DOWN ABOUT 10 KNOTS FROM THE PREVIOUS RUN, NOW PEAKING AROUND 50-60 KNOTS. THE SHIPS PACKAGE CONTINUES TO BE QUITE BEARISH, WITH A PEAK BETWEEN 35-40 KNOTS. THE JTWC FORECAST PEAKS AT 55 KNOTS, WITH THE CAVEAT THAT SOME ADDITIONAL INTENSIFICATION COULD OCCUR IN THE PERIOD AFTER TAU 36 AND LANDFALL. AFTER LANDFALL, THE SYSTEM WILL RAPIDLY WEAKEN AND DISSIPATE BY TAU 96, IN LINE WITH THE BULK OF THE GUIDANCE PACKAGE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN