WDPN31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (WUTIP) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.7N 108.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 186 NM EAST-SOUTHEAST OF HANOI, VIETNAM
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AFTER REMAINING RELATIVELY STATIONARY FOR ABOUT SIX HOURS AS THE
SYSTEM NEARED THE SUBTROPICAL RIDGE AXIS, TROPICAL STORM (TS) 01W
(WUTIP) ROUNDED THE AXIS AND SCOOTED OFF TO THE NORTHEAST, MAKING A
BRIEF EXCURSION OVER THE FAR WESTERN PORTION OF HAINAN ISLAND,
AFTER MAKING LANDFALL SOUTH OF DONGFANG NEAR 1300Z. THE SYSTEM
EMERGED BACK OVER WATER AROUND 1700Z AND HAS CONTINUED ON A
NORTH-NORTHEASTWARD TRAJECTORY SINCE THAT TIME.  ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM REGENERATING
AFTER EXPERIENCING SOME EROSION WHILE CROSSING OVER HAINAN. CLOUD
TOPS HAVE COOLED SIGNIFICANTLY, THOUGH THE PREVIOUSLY EVIDENT EYE
FEATURE HAS DISAPPEARED. A 131736Z GMI COLOR-ENHANCED 91GHZ
MICROWAVE IMAGE REVEALED A SMALL AMOUNT OF VORTEX TILT, WITH THE
LOW LEVEL CIRCULATION CENTER (LLCC) DISPLACED SLIGHTLY NORTH OF THE
DEEPEST CONVECTION. THE LATEST CIMSS ANALYSIS SHOWS ABOUT 10 KNOTS
OF NORTHEASTERLY SHEAR, WHICH IS DRIVING THE MODEST VORTEX TILT.
RADAR IMAGERY SHOWS A MUCH MORE RAGGED LLCC THAN WHEN THE SYSTEM
MADE LANDFALL, BUT THE MOST RECENT DATA SUGGESTS SOME
REORGANIZATION. THE INITIAL POSITION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON BOTH THE RADAR DATA AND MICROWAVE IMAGERY
DISCUSSED ABOVE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM
CONFIDENCE, IN LINE WITH THE SLIGHTLY LOWER OBJECTIVE INTENSITY
ESTIMATES OUTLINED ABOVE. THE ENVIRONMENT REMAINS FAVORABLE OVERALL,
THOUGH PROXIMITY TO LAND WILL NEGATIVELY IMPACT THE SYSTEM TO SOME
DEGREE.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN EDGE OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED SOUTH OF JAPAN. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.0 - 65 KTS
   CIMSS SATCON: 52 KTS AT 131720Z
   CIMSS ADT: 45 KTS AT 131820Z
   CIMSS AIDT: 48 KTS AT 131820Z
   CIMSS D-MINT: 50 KTS AT 131733Z
   CIMSS D-PRINT: 54 KTS AT 131800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: HAVING ROUND THE RIDGE AXIS, AND LEAVING
HAINAN ISLAND IN ITS WAKE, TS 01W WILL NOW ACCELERATE
NORTH-NORTHEASTWARD ALONG THE WESTERN SIDE OF THE RIDGE. AN
UPPER-LEVEL TROF MOVING IN FROM THE WEST WILL STRENGTHEN THE
DEEP-LAYER GRADIENT FLOW, GIVING TS 01W AN EXTRA BOOST IN FORWARD
SPEED AFTER TAU 12. THE SYSTEM IS EXPECTED TO MAKE A SECOND
LANDFALL NEAR THE FAR EASTERN PORTION OF THE BEIBU GULF, WEST OF
ZHANJIANG BY TAU 12. THE SYSTEM WILL THEN TRACK NORTHEASTWARD OVER
SOUTHERN CHINA THROUGH THE REMAINDER OF THE FORECAST PERIOD. IN
TERMS OF INTENSITY, VERY WARM WATERS WILL PROVIDE AMPLE ENERGY FOR
THE SYSTEM TO REINTENSIFY. AN UPPER-LEVEL ANTICYCLONE DIRECTLY OVER
TOP OF THE SYSTEM WILL PROVIDE GOOD OUTFLOW CONDITIONS, WHICH WILL
BEGIN TO IMPROVE SHORTLY, AS THE SYSTEM BEGINS TO TAP INTO THE
DIVERGENT FLOW AHEAD OF THE APPROACHING TROF. THE FORECAST CALLS
FOR THE SYSTEM TO BE AROUND 60 KNOTS BY TAU 12, WHERE IT WILL
ALREADY BE OVER LAND. HOWEVER, THE FAVORABLE CONDITIONS WILL ALLOW
FOR A PERIOD OF VERY FAST INTENSIFICATION, WITH PEAK INTENSITY
LIKELY TO REACH TYPHOON STRENGTH WITHIN THE NEXT 6-12 HOURS, PRIOR
TO THE SYSTEM MAKING ITS SECOND LANDFALL. ONCE OVER LAND, TS 01W
WILL STEADILY WEAKEN OVER THE RUGGED TERRAIN OF SOUTHERN CHINA,
DISSIPATING AS A TROPICAL CYCLONE BY TAU 48. 

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN
STRONG AGREEMENT, WITH MINIMAL CROSS- OR ALONG-TRACK SPREAD THROUGH
THE FIRST 36 HOURS OF THE FORECAST. ALONG-TRACK SHOWS A MODERATE
INCREASE AFTER TAU 36 AS THE MODELS BEGIN TO LOSE THE VORTEX. THE
JTWC FORECAST IS CONSISTENT WITH THE CONSENSUS MEAN THROUGH THE
FORECAST PERIOD WITH HIGH CONFIDENCE. THE BULK OF THE INTENSITY
GUIDANCE SHOWS STEADY WEAKENING FROM THE START OF THE FORECAST,
WTIH THE NOTABLE EXCEPTION OF HWRF, WHICH DEPICTS ABOUT 5-10 KNOTS
OF INTENSIFICATION THROUGH TAU 12. THE JTWC FORECAST IS PLACED ON
TOP OF THE HWRF FORECAST, IN AGREEANCE THAT THE SYSTEM WILL LIKELY
INTENSIFIFY IN THE IMMEDIATE SHORT-TERM PRIOR TO LANDFALL. 

FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH
INTENSITY 0 - 72 HR: MEDIUM//
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