WDPN31 PGTW 241500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (DOKSURI) WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.5N 125.8E
   INITIAL INTENSITY: 120 KTS
   GEOGRAPHIC REFERENCE: 569 NM SOUTH-SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
HAVING TURNED TOWARDS THE NORTHWEST ABOUT SIX HOURS AGO, TYPHOON
(TY) 05W (DOKSURI) HAS NOW PICKED UP SPEED, TO ABOUT 9 KNOTS,
THOUGH IT IS ALREADY STARTING TO EXHIBIT SOME TROCHOIDAL WOBBLES ON
THE NORTHWEST TRACK. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY OVER THE PREVIOUS SIX HOURS INDICATES THE SYSTEM WENT
THROUGH A SHORT WEAKENING CYCLE, FOLLOWED BY ANOTHER BURST OF
INTENSIFICATION WHICH PEAKED RIGHT AT 1200Z, WITH THE EYE
TEMPERATURE REACHING 20C AND CLOUD TOPS COOLING TO -75C, WITH THE
COLDEST CLOUD TOPS COMPLETELY ENCIRCLING THE 25NM WIDE EYE.
HOWEVER, OVER JUST THE LAST HOUR, THE ROBUST EYEWALL APPEARS TO BE
WEAKENING SLIGHTLY ON THE NORTHWEST SIDE AS THE EYEWALL CONVECTION
CONTINUES TO PULSE. A 241314Z GPM 89GHZ MICROWAVE IMAGE SHOWS THAT
THE STATIONARY BANDING COMPLEX (SBC) WHICH WAS PRESENT IN EARLIER
IMAGERY REMAINS FIRMLY ENTRENCHED ALONG THE SOUTHERN PERIPHERY OF
THE SYSTEM, AND THE ASSOCIATED MOAT OF RELATIVELY DRY AIR DEVOID OF
CONVECTION, NOW EXTENDS ALL THE WAY TO THE SOUTHEASTERN QUADRANT.
THIS SETUP MARKS THE EARLY STAGES OF AN EYEWALL REPLACEMENT CYCLE
(EWRC). THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED
ON THE EYE FEATURE IN THE EIR, THE GPM IMAGE NOTED ABOVE AND
EXTRAPOLATION OF AN EYE FEATURE IN A 240952Z RCM-3 SAR IMAGE. THE
INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON A BLEND
OF THE AGENCY DVORAK INTENSITY FIXES, HEDGED SLIGHTLY HIGHER IN
LIGHT OF THE ADT AND AIDT ESTIMATE OF 119 KNOTS. THE SAR WINDSPEED
MEASUREMENTS SHOWED A MAX OF 100 KNOTS, BUT DUE TO THE VERY HIGH
INCIDENCE ANGLE ABOVE 50 DEGREES, THESE WINDS THESE WINDS MAY BE A 
FEW 
KNOTS TOO LOW. THE SYSTEM IS STILL TAPPING INTO THE POLEWARD OUTFLOW 
CHANNEL INTO THE CUTOFF LOW SOUTH OF KYUSHU, WITH EASTWARD OUTFLOW 
BEING ENHANCED BY THE DEVELOPMENT OF AN UPPER-LEVEL ANTICYCLONE TO 
THE 
SOUTHEAST NEAR 15N 130E. SHEAR REMAINS VERY LOW AND SSTS ARE NEAR 
30C, 
PROVIDING AN OVERALL FAVORABLE ENVIRONMENT.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED JUST EAST OF CENTRAL HONSHU. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T6.5 - 127 KTS
   KNES: T6.0 - 115 KTS
   CIMSS ADT: 124 KTS AT 241130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: MODERATE EQUATORWARD OUTFLOW. 

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: THE RIDGE PATTERN STEERING TY DOKSURI TO THE
NORTHWEST IS STARTING TO FIRM UP, WITH THE PRIMARY STR CENTERED TO
THE EAST OF TOKYO, EXPANDING SOUTHWARD TO LINK UP WITH THE
DEVELOPING ANTICYCLONE POSITIONED TO THE EAST OF TY 05W. THE LATEST
GLOBAL MODEL FIELDS SUGGEST THIS RIDGE COMPLEX WILL SHIFT EASTWARD
BUT REMAIN ORIENTED ON A GENERAL NORTHWEST-SOUTHEAST AXIS THROUGH
TO A NORTH-SOUTH AXIS THROUGH TAU 72 BEFORE SHIFTING TO A MORE
NORTH-SOUTH AXIS THEREAFTER. THIS WILL ALLOW FOR TY 05W TO CONTINUE
TRACKING NORTHWESTWARD THROUGH THE MAJORITY OF THE FORECAST, BEFORE
TURNING MORE NORTHWARD TOWARDS THE LATER PORTION OF THE FORECAST
PERIOD. THE EXACT ORIENTATION OF THE RIDGE WILL HAVE A SIGNIFICANT
IMPACT ON THE TRACK OF TY 05W, WHICH WHEN COMBINED WITH THE WOBBLES
FREQUENTLY ASSOCIATED WITH STRONG TYPHOONS, INTRODUCES UNCERTAINTY
INTO THE EXACT TRACK IN THE FIRST 72 HOURS OF THE FORECAST. THE
SYSTEM IS EXPECTED TO SKIRT THE NORTHEAST TIP OF LUZON BY TAU 24,
THEN TRACK SOUTHWEST OF TAIWAN AFTER TAU 48, MAKING LANDFALL ALONG
THE EASTERN COAST OF CHINA NEAR XIAMEN AFTER TAU 72. FROM AN
INTENSITY PERSPECTIVE, THE SYSTEM HAS LIKELY ALREADY REACHED ITS
PEAK INTENSITY, OR WILL WITHIN THE NEXT 6 TO 12 HOURS. WHILE SHEAR,
OUTFLOW AND OCEAN CONDITIONS REMAIN FAVORABLE, THE PRIMARY
INFLUENCE IN THE NEAR-TERM INTENSITY FORECAST WILL BE THE ONSET OF
THE EWRC. AS DISCUSSED ABOVE, THE LATEST MICROWAVE IMAGERY
INDICATES THE PROCESS HAS ALREADY STARTED OR WILL IMMINENTLY. ONCE
THE SECONDARY EYEWALL FORMATION (SEF) PROCESS STARTS IN EARNEST,
THE INTENSITY WILL DROP QUICKLY, THOUGH THE DURATION OF THE CYCLE
AND THE AMOUNT OF WEAKENING IS UNPREDICTABLE. THE CURRENT FORECAST
CALLS FOR ABOUT 15 KNOTS OF WEAKENING DUE TO THE EWRC, WITH A SLOW
PACE OF WEAKENING TO TAU 48 AS THE SYSTEM ATTEMPTS TO RECOVER. THE
COMBINATION OF DECREASING SSTS AND UPPER-LEVEL OUTFLOW AND
DISRUPTION OF THE LOW-LEVEL FLOW DUE TO TERRAIN INFLUENCES PASSING
TAIWAN, WILL RESULT IN A MORE RAPID PACE OF WEAKENING AS THE SYSTEM
APPROACHES LANDFALL. THE SYSTEM WILL LIKELY DISSIPATE BY TAU 120 TO
THE WEST OF SHANGHAI.

MODEL DISCUSSION: THE GUIDANCE ENVELOPE FOR THE 1200Z RUN IS
TIGHTLY CONSTRAINED AND IN MUCH BETTER AGREEMENT THAN PREVIOUS
MODEL RUNS. EVEN THE NAVGEM HAS NOW JOINED THE PACK, MEANING THERE
ARE NO LONGER ANY DETERMINISTIC OR ENSEMBLE MEAN TRACKERS
INDICATING A TRACK OVER LUZON. THE GUIDANCE ENVELOPE GRADUALLY
EXPANDS TO 105NM BY TAU 48, AND 165NM BY TAU 72. GFS CONTINUES TO
BE THE EASTERN OUTLIER, TAKING THE SYSTEM OVER THE SOUTHWEST COAST
OF TAIWAN BETWEEN TAUS 48 AND 72 THEN RECURVING THE SYSTEM RAPIDLY
POLEWARD THROUGH TAU 120. THE NAVGEM, UKMET, AND ECMWF ON THE OTHER
HAND, LIE WEST OF THE CONSENSUS MEAN AND TAKE THE SYSTEM ON A
STRAIGHT NORTHWEST TRACK THROUGH TAU 120, DEEP INTO SOUTHERN CHINA.
THE JTWC FORECAST LIES JUST NORTH AND EAST OF THE CONSENSUS MEAN. AS
MENTIONED ABOVE, TRACK WOBBLES AND VARIATIONS IN THE ORIENTATION OF
THE STEERING RIDGE INTRODUCE UNCERTAINTY IN THE EXACT TRACK THROUGH
THE FIRST 72 HOURS, LEADING TO AN OVERALL MEDIUM CONFIDENCE. 
INTENSITY GUIDANCE IS IN VERY GOOD AGREEMENT ON A SMALL AMOUNT OF
ADDITIONAL INTENSIFICATION THROUGH TAU 12 FOLLOWED BY GENERAL
WEAKENING THROUGH THE REMAINDER OF THE FORECAST. THE JTWC FORECAST
LIES CLOSE TO THE CONSENSUS MEAN BUT THE UNCERTAINTY SURROUNDING THE
TIMING OF ONSET, DURATION, AND IMPACT ON THE INTENSITY OF THE EWRC,
THE FORECAST IS MADE WITH MEDIUM CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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