WDPN31 PGTW 270900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (DOKSURI) WARNING NR 024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.1N 119.3E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 269 NM SOUTH-SOUTHWEST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 33 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND A RECENT 270530Z
AMSR2 89GHZ MICROWAVE IMAGE INDICATES THAT TYPHOON (TY) 05W
(DOKSURI) IS IN THE MIDST OF ANOTHER EYEWALL REPLACEMENT CYCLE
(ERC), WITH A SMALL (35NM) INNER CORE OF DEEP CONVECTION WITH A
NASCENT PINHOLE EYE, SURROUNDED BY A MOAT AND AN OUTER EYEWALL OUT
55NM TO 70NM FROM THE CENTER. THE ANIMATED MSI SHOWS THAT DEEP
CONVECTION AND VORTICAL HOT TOWERS (VHTS) ARE RAPIDLY CONSOLIDATING
AROUND THE DEVELOPING EYE WHILE THE OUTER EYEWALL REMAINS FAIRLY
ROBUST AS WELL. COMPARISON OF THE AMSR2 IMAGERY WITH AN EARLIER
ATMS 88GHZ IMAGE SUGGESTS THE OUTER EYEWALL IS ALREADY STARTING TO
SHRINK DOWN. ANALYSIS OF CWB RADAR IMAGERY SHOWS THAT THE SYSTEM
TOOK A SHARP WESTWARD TURN FROM APPROXIMATELY 0000Z-0300Z, BEFORE
TURNING NORTHWARD AGAIN. THE INITIAL POSITION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE PINHOLE EYE IN BOTH THE MSI AND THE AMSR2
IMAGE. IN TERMS OF INTENSITY, THE BULK OF THE OBJECTIVE ESTIMATES
ARE STRUGGLING WITH THE SMALL NATURE OF THE INNER CORE AND THUS ARE
SIGNIFICANTLY TOO LOW. THE DMINT HOWEVER IS 80 KNOTS, AND SATCON IS
AROUND 75 KNOTS, BOTH OF WHICH SUPPORT EARLIER 272200Z SENTINEL-1
AND RCM-3 SAR MEASUREMENTS OF 79 KNOTS. THE TURN WAS SHARP ENOUGH
TO WARRANT AN INTERMEDIATE 0300Z POSITION. ANALYSIS REVEALS THE
SYSTEM IS MOVING INTO AN AREA OF LOW (5-10 KNOTS) VWS AND IS
STARTING TO TAP INTO A POLEWARD OUTFLOW CHANNEL INTO AN UPPER-LEVEL
LOW PARKED WEST OF SHANGHAI, IN ADDITION TO THE ALREADY STRONG
EQUATORWARD CHANNEL. SSTS ARE INCREASING AS THE SYSTEM EXITS THE
AREA OF UPWELLING NORTH OF LUZON, AND AS THE SYSTEM APPROACHES THE
SHALLOW COAST OF CHINA, COASTAL DOWNWELLING WILL LIKELY RESULT IN
INCREASED SSTS AND OHC RIGHT ALONG THE COAST. BOTH THE RADIUS OF
MAXIMUM WINDS (RMW) AND THE 34 KNOT WIND RADII HAVE BEEN REDUCED
BASED ON ANALYSIS OF SAR AND ASCAT DATA.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 75 KTS AT 270129Z
   CIMSS ADT: 59 KTS AT 270530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: THROUGH THE NEXT FEW HOURS, THE COMBINED
INFLUENCE OF THE ERC AND SOME LINGERING EFFECTS FROM THE PROXIMITY
OF TAIWAN, TY 05 IS LIKELY TO CONTINUE TO WOBBLE A BIT, THOUGH
TRACK GENERALLY TOWARDS THE NORTHWEST UNDER THE GENERAL STEERING
INFLUENCE OF THE STRONG STR TO THE NORTHEAST. THE SYSTEM IS
EXPECTED TO MAKE LANDFALL ALONG THE CHINESE COAST IN THE VICINITY
OF XIAMEN, CHINA BY AROUND TAU 18. AS DISCUSSED ABOVE, SEVERAL
FACTORS ARE AT PLAY THAT WILL INFLUENCE THE INTENSITY FORECAST.
FIRST, THE SYSTEM IS TAPPING INTO A STRONG POLEWARD OUTFLOW CHANNEL
INTO AN UPPER-LEVEL LOW WEST OF SHANGHAI, PROVIDING ADDITIONAL
OUTFLOW TO THE ALREADY EXISTING STRONG EQUATORWARD OUTFLOW CHANNEL.
THOUGH THE UPPER-LEVEL LOW WILL FILL OVER THE NEXT 24 HOURS,
OUTFLOW WILL CONTINUE FLOWING NORTHWARD LONG ENOUGH TO SUPPORT
INTENSIFICATION PRIOR TO LANDFALL. ADDITIONALLY, THE WARM SSTS
ALREADY IN PLACE ALONG THE COAST OF CHINA WILL LIKELY INCREASE AS
THE STORM APPROACHES DUE TO COASTAL DOWNWELLING, PROVIDING A BOOST
IN ENERGY TO SUPPORT INTENSIFICATION. LASTLY, AS THE SYSTEM MOVES
CLEAR OF TAIWAN AND INTO THE SOUTHERN END OF THE TAIWAN STRAIT,
SOME FUNNELING AND FRICTIONAL EFFECTS WILL HELP SUPPORT A DECREASE
IN THE OUTER EYEWALL, ALSO SUPPORTING INTENSIFICATION. THE NET
EFFECT WILL BE A FORECASTED INCREASE TO AT LEAST 90 KNOTS BY TAU
12, WITH A POTENTIAL HIGHER PEAK OCCURRING JUST PRIOR TO LANDFALL
AROUND TAU 18. AFTER LANDFALL, TY 05W WILL TRAVEL NORTH-NORTHWESTWARD 
ALONG THE WEST SIDE OF THE STEERING RIDGE, ULTIMATELY DISSIPATING WEST 
OF SHANGHAI BY TAU 48.  

MODEL DISCUSSION: AVAILABLE TRACK GUIDANCE IS IN VERY TIGHT
AGREEMENT ON THE NORTH-NORTHWEST TRACK THROUGH THE FORECAST PERIOD
BUT CANNOT CAPTURE THE LIKELY NEAR-TERM WOBBLES IN THE TRACK
DISCUSSED ABOVE. TRACK SPEEDS WILL BE RELATIVELY SLOW FOR THE FIRST
12 HOURS AS THE WOBBLES SLOW THE EFFECTIVE FORWARD SPEED, BUT TRACK
SPEEDS PICK UP FROM THERE THROUGH LANDFALL. THE JTWC FORECAST IS
CONSISTENT WITH THE PREVIOUS FORECAST, AND LIES NEAR THE CONSENSUS
MEAN WITH HIGH CONFIDENCE. THE INTENSITY GUIDANCE IS ALSO IN GOOD
AGREEMENT, BUT WITH THIS RUN THE BULK OF THE GUIDANCE HAS BACKED
OFF NEAR-TERM INTENSIFICATION, WITH THE EXCEPTION OF COAMPS-TC
(GFS). THE JTWC FORECAST DEVIATES FROM THE GUIDANCE IN INTENSIFYING
THE SYSTEM PRIOR TO LANDFALL BUT THEN REJOINS THE PACK THROUGH THE
REMAINDER OF THE FORECAST. CONFIDENCE IS THUS MEDIUM THROUGH THE
FORECAST PERIOD. 

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