WDPN31 PGTW 210900

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//

SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (DUJUAN) WARNING NR 024//

RMKS/

1. FOR METEOROLOGISTS.

2. 6 HOUR SUMMARY AND ANALYSIS.



SUMMARY:

   INITIAL POSITION: 33.7N 139.8E

   INITIAL INTENSITY: 70 KTS

   GEOGRAPHIC REFERENCE: 96 NM SOUTH OF YOKOSUKA, JAPAN

   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 16 KTS

   SIGNIFICANT WAVE HEIGHT: 32 FEET



SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:

ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY)

24W

(DUJUAN) UNDERGOING A PRONOUNCED RECONSOLIDATION PHASE, CHARACTERIZED

BY SPIRAL BANDS OF DEEP CONVECTION WRAPPING TIGHTLY INTO A LOW-LEVEL

CIRCULATION CENTER (LLCC) FULLY OBSCURED BY A ROBUST CENTRAL DENSE

OVERCAST (CDO). THIS BRIEF STRENGTHENING TIMEFRAME IS DRIVEN PRIMARILY

BY A VERY STRONG POLEWARD OUTFLOW CHANNEL, SUPPORTED BY CONDUCIVE SEA

SURFACE TEMPERATURES (SST) OF 27-28 C, AND INCREASING BUT STILL LOW TO

MODERATE (15-20 KTS) VERTICAL WIND SHEAR (VWS). THE SYSTEM HAS BEEN

ABLE TO TRANSIENTLY COCOON ITSELF FROM THE SURROUNDING DRY-AIR

ADVECTION ENTRAINING INTO THE INNER VORTEX CORE. THE INITIAL POSITION

IS PLACED WITH HIGH CONFIDENCE BASED ON A FUSION OF RADAR IMAGERY AND

A

210556Z F18 SSMIS 91 GHZ MICROWAVE PASS. THE INITIAL INTENSITY OF 70

KTS IS ALSO ASSESSED WITH HIGH CONFIDENCE, SUPPORTED BY OBSERVED

CONVECTIVE CONSOLIDATION, INCREASED DVORAK AGENCY ESTIMATES, AND THE

AUTOMATED OBJECTIVE AIDS LISTED BELOW.



INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK AND A 210051Z

METOP-C ASCAT



CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) CENTERED TO THE

EAST



AGENCY DVORAK AND AUTOMATED FIXES:

   PGTW: T4.5 - 77 KTS

   RJTD: T5.0 - 90 KTS

   RCTP: T4.5 - 77 KTS

   CIMSS SATCON: 63 KTS AT 210422Z

   CIMSS ADT: 55 KTS AT 210530Z

   CIMSS AIDT: 54 KTS AT 210530Z

   CIMSS D-MINT: 71 KTS AT 210422Z

   CIMSS D-PRINT: 82 KTS AT 210630Z



FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE

   VWS: 15-20 KTS

   SST: 27-28 CELSIUS

   OUTFLOW: STRONG POLEWARD

   OTHER FACTORS: DRY AIR ENTRAINMENT



ANALYSIS CONFIDENCE:

   INITIAL POSITION: HIGH

   INITIAL INTENSITY: HIGH

   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 DUJUAN IS FORECAST TO ACCELERATE ALONG A

NORTHEASTWARD TRANSLATION VECTOR OVER THE NEXT 12 HOURS AND MAINTAIN

THIS TRACK THROUGHOUT THE PREDICTION TIMEFRAME, COMMITTED TO THE

NORTHWESTERN FLANK OF THE SUBTROPICAL RIDGE ANCHORED TO THE EAST. THE

CLOSEST POINT OF APPROACH (CPA) TO YOKOSUKA, JAPAN IS ESTIMATED AT 81

NM AND EXPECTED TO OCCUR WITHIN THE NEXT 6 HOURS. DURING THIS TIME,

MODEST DEEPENING TO A PEAK INTENSITY OF 75 KTS IS PROJECTED UNDER A

MARGINALLY CONDUCIVE THERMODYNAMIC AND SYNOPTIC ENVIRONMENT. THIS

TRANSIENT STRENGTHENING PHASE IS SUPPORTED BY TY 24W BRIEFLY SHIELDING

ITSELF FROM HOSTILE DRY-AIR ENTRAINMENT WHILST TAPPING INTO VERY

STRONG POLEWARD OUTFLOW. SUBSEQUENT TO CPA PASSAGE AT YOKOSUKA, THE

VORTEX IS FORECAST TO TRACK DIRECTLY ACROSS THE THERMALLY CONDUCIVE

TAIL END OF THE KUROSHIO CURRENT (28-29 C) SHORTLY AFTER TAU 12.

HOWEVER, THE ONSET OF EXTRATROPICAL TRANSITION (ETT) WILL INITIATE AS

THERMODYNAMIC CONDITIONS DEGRADE OVER RAPIDLY COOLING SEA SURFACE

TEMPERATURES, COUPLED WITH RELENTLESS DRY AIR ADVECTION AND

DESTRUCTIVE VERTICAL WIND SHEAR REACHING 40+ KTS BY TAU 36. UPON

INTERACTING WITH THE STRONG BAROCLINIC REGIME AND THE UPPER-LEVEL MID-

LATITUDE WESTERLIES, TY DUJUAN WILL COMPLETE ETT BY THE END OF THE

FORECAST TIMEFRAME.



MODEL DISCUSSION: HIGH CONFIDENCE ANCHORS THE OFFICIAL JTWC TRACK

FORECAST, POSITIONED CLOSE TO THE MULTI-MODEL DYNAMICAL CONSENSUS IN

LIGHT OF EXCELLENT NUMERICAL MODEL AGREEMENT. ALL MAJOR PREDICTION

TRACKERS RESOLVE AN EXTREMELY TIGHT (5 NM) CROSS-TRACK DISPERSION

ENVELOPE AT THE CPA TO YOKOSUKA. ALONG-TRACK SPREAD INCREASES TO 150

NM BY TAU 36 AS THE SYSTEM COMPLETES ITS ETT. REGARDING INTENSITY

OUTLOOKS, HAFS AND COAMPS-TC CONTRAST STATISTICAL-DYNAMICAL SCENARIOS

PROGNOSTICATING MONOTONIC CYCLOLYSIS BY DEPICTING A MINOR RE-DEEPENING

TREND OVER THE NEXT 12 HOURS TOWARD A PEAK WIND SPEED PREDICTION OF

75-80 KTS. AFTER THAT, ALL AVAILABLE GUIDANCE PROJECTS RAPID WEAKENING

AS THE SYSTEM ENTERS THE HOSTILE BAROCLINIC ZONE. THE OFFICIAL JTWC

INTENSITY FORECAST CONVERGES NARROWLY NEAR THE DYNAMICAL CONSENSUS

WITH HIGH CONFIDENCE.



FORECAST CONFIDENCE:

   TRACK 00-72 HR: HIGH

   INTENSITY 00-72 HR: HIGH//

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