WDPN31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01W (WUTIP) WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.3N 109.1E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 185 NM EAST-SOUTHEAST OF HANOI, VIETNAM
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND ENHANCED
INFRARED (EIR) IMAGERY SHOW THAT DEEP CONVECTION HAS FOR THE MOST
PART COLLAPSED OVER THE LAST COUPLE OF HOURS AS TYPHOON (TY) 01W
(WUTIP) MOVED AWAY FROM HAINAN AND TOWARDS THE SOUTH COAST OF
CHINA. BUT WHILE THE CONVECTION HAS WEAKENED OR DISSIPATED, THE LOW
LEVEL CIRCULATION CENTER (LLCC) HAS CONTINUED TO TIGHTEN UP, AND IS
NOW VERY WELL-DEFINED. ANIMATED RADAR IMAGERY FROM CMA SHOWS A 15NM
EYE WITH SHALLOW TO MODERATE CONVECTIVE ACTIVITY SURROUNDING THE
SMALL EYE FEATURE. THE INITIAL POSITION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE MSI AND RADAR DATA. THE INITIAL INTENSITY
IS ASSESSED WITH MEDIUM CONFIDENCE, BASED ON THE AVERAGE OF THE
AGENCY DVORAK CURRENT INTENSITY ESTIMATES AND THE GENERAL
IMPROVEMENT IN THE OVERALL STRUCTURE, ESPECIALLY IN THE RADAR, OVER
THE PAST SIX HOURS. THE ENVIRONMENT REMAINS FAVORABLE, WITH VERY
WARM SSTS, LOW VWS AND STRONG RADIAL OUTFLOW ALOFT. WATER VAPOR
IMAGERY SHOWS A SHARP TROF AXIS CURRENTLY PASSING THE VIETNAM-CHINA
BORDER REGION, ALLOWING FOR AN INCREASE IN POLEWARD OUTFLOW.
HOWEVER, THE SHORT TIME REMAINING OVER WATER AND FLOW DISRUPTION
DUE TO PROXIMITY TO LAND, ARE CURRENTLY THE PRIMARY LIMITING
FACTORS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.0 - 65 KTS
   CIMSS SATCON: 53 KTS AT 132000Z
   CIMSS ADT: 49 KTS AT 140020Z
   CIMSS AIDT: 53 KTS AT 140020Z
   CIMSS D-MINT: 55 KTS AT 131837Z
   CIMSS D-PRINT: 50 KTS AT 132300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: DEVELOPING POLEWARD OUTFLOW CHANNEL.

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: TY 01W IS FORECAST TO CONTINUE TRACKING
NORTHEASTWARD ALONG THE WESTERN SIDE OF A STRENGTHENING RIDGE
THROUGH THE FORECAST PERIOD. FORWARD SPEED SHOULD PICK UP STEADILY
AS THE TROF MOVING IN FROM THE WEST MOVES CLOSER AND TIGHTENS UP
THE GRADIENT BETWEEN THE TROF AND THE STR TO THE NORTHEAST.
LANDFALL ALONG THE FAR NORTHEASTERN COAST OF THE BEIBU GULF, TO THE
WEST OF ZHANJIANG, CHINA WITHIN THE NEXT FEW HOURS. THE SYSTEM WILL
THEN CONTINUE FURTHER INLAND OVER SOUTHERN CHINA THROUGH 36. IN
TERMS OF INTENSITY, THE SYSTEM MAY HAVE ONE LAST GASP OF
INTENSIFICATION UP ITS SLEEVE, AS THE LATEST MSI SHOWS DEEP
CONVECTION REDEVELOPING UPSHEAR OF THE LLCC. THUS, A SHORT BURST OF
ADDITIONAL INTENSIFICATION IS POSSIBLE JUST PRIOR TO LANDFALL BUT
DUE TO THE PROXIMITY TO LAND, WILL BE EXTREMELY SHORT-LIVED. ONCE
THE SYSTEM MOVES INLAND, IT WILL WEAKEN RAPIDLY OVER THE ROUGH
TERRAIN AND DISSIPATE AS A TROPICAL CYCLONE BY TAU 36. 

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE REMAINS
IN TIGHT AGREEMENT THROUGHOUT THE FORECAST PERIOD, PROVIDING HIGH
CONFIDENCE TO THE JTWC FORECAST, WHICH IS PLACED NEAR THE
MULTI-MODEL CONSENSUS. INTENSITY GUIDANCE IS ALSO IN GOOD
AGREEMENT, WITH NONE OF THE CONSENSUS MEMBERS INDICATING ANYTHING
OTHER THAN STEADY WEAKENING FROM TAU 00. THE POSSIBILITY OF A VERY
BRIEF INTENSIFICATION PRIOR TO LANDFALL IS TOO TEMPORALLY LIMITED TO
BE CAPTURED IN THE MODEL DATA. HOWEVER, ALL MODELS AGREE THAT A
RAPID WEAKENING WILL OCCUR IMMEDIATELY AFTER LANDFALL, WITH
DISSIPATION BY TAU 36.  

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