WDPN32 PGTW 021500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (TEN) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.6N 111.0E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 182 NM EAST-NORTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THE
PREVIOUSLY EXPOSED LOW-LEVEL CIRCULATION CENTER INCORPORATING WITH
FLARING CONVECTION IN THE SOUTHWEST QUADRANT AS THE SYSTEM APPEARS
TO BE REORGANIZING AROUND THE BROADER SURROUNDING CYCLONIC
CIRCULATION. LACKING ANY RECENT SCATTEROMETER DATA TO FURTHER
ILLUMINATE THE NATURE OF THE BROADER CIRCULATION, THE INITIAL
POSITION IS PLACED WITH LOW CONFIDENCE NEAR THE CENTER OF THE
LOW-LEVEL WIND FIELD EXPOSED IN THE ANIMATED EIR. WITH THE
REORGANIZATION UNDERWAY, THE INITIAL INTENSITY IS HELD AT 30 KTS
WITH MEDIUM CONFIDENCE, SUPPORTED BY THE AGENCY DVORAK FIXES AND
CIMSS OBJECTIVE INTENSITY ESTIMATES. THE ENVIRONMENT IS
CHARACTERIZED AS MARGINAL WITH WARM (29-30 C) SEA SURFACE
TEMPERATURES AND MODERATE EQUATORWARD OUTFLOW BEING OFFSET BY 15-20
KTS OF NORTHEASTERLY VERTICAL WIND SHEAR (VWS).

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED SOUTHEAST OF KYUSHU

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 35 KTS AT 021140Z
   CIMSS AIDT: 33 KTS AT 021140Z
   CIMSS D-MINT: 28 KTS AT 021118Z
   CIMSS D-PRINT: 25 KTS AT 021140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   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: TROPICAL DEPRESSION (TD) 10W HAS SLOWED ITS
TRACK SPEED OVER THE PAST 6 HOURS AS THE LOW-LEVEL CIRCULATION
REORGANIZES. THE TRACK IS EXPECTED TO RESUME A NORTHWESTWARD
TRAJECTORY TOWARD HAINAN ISLAND WITHIN THE NEXT 12 HOURS UNDER THE
STEERING INFLUENCE OF THE STR TO THE NORTHEAST. INITIAL LANDFALL
ALONG THE SOUTHEASTERN COAST OF HAINAN IS FORECAST SHORTLY BEFORE
TAU 18, THEN 10W IS EXPECTED TO REEMERGE OVER WATER IN THE GULF OF
TONKIN JUST BEFORE TAU 30, WITH A SECOND LANDFALL NEAR THE
SINO-VIETNAMESE BORDER REGION SHORTLY BEFORE TAU 48. THE DECAYING
REMNANTS WILL THEN TRACK INLAND OVER MAINLAND CHINA ON A
NORTH-NORTHEASTERLY TRACK FOR THE REMAINDER OF THE FORECAST PERIOD.
THERE IS EXPECTED TO BE A BRIEF WINDOW OF OPPORTUNITY FOR THE
SYSTEM TO INTENSIFY BEFORE TRACKING OVER HAINAN, THEN ANOTHER BRIEF
PERIOD OF INTENSIFICATION OVER THE GULF OF TONKIN, REACHING A PEAK
OF 40 KTS JUST BEFORE THE SECOND LANDFALL. 

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN OVERALL AGREEMENT
ABOUT THE EVENTUAL NORTHWESTWARD TRAJECTORY OVER HAINAN ISLAND AND
A SECOND LANDFALL NEAR THE SINO-VIETNAMESE BORDER REGION, WITH A
CROSS-TRACK SPREAD OF 95 NM AT TAU 48. THE GFS DETERMINISTIC AND
THE GFS ENSEMBLE MEAN COMPRISE THE EASTERNMOST SOLUTIONS WHILE THE
EXPERIMENTAL GOOGLE DEEPMIND IS THE WESTERNMOST SOLUTION. THE JTWC
TRACK FORECAST IS PLACED SLIGHTLY TO THE WEST OF THE MULTI-MODEL
CONSENSUS, HEDGED CLOSER TO THE GOOGLE DEEPMIND WITH MEDIUM
CONFIDENCE THROUGHOUT THE FORECAST PERIOD. MODEL INTENSITY GUIDANCE
DEPICTS A CONTINUOUS INTENSIFICATION UNTIL THE SECOND LANDFALL,
THEN RAPID WEAKENING OVER LAND. THE JTWC INTENSITY FORECAST IS
PLACED BELOW THE MULTI-MODEL CONSENSUS FOR THE PERIOD OF TIME THAT
THE SYSTEM IS TRANSITING OVER HAINAN ISLAND, THEN FOLLOWS CLOSELY
TO THE ULTIMATE WEAKENING TREND DEPICTED BY THE CONSENSUS MODELS.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM//
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