WDPN31 PGTW 182100

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

SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (DUJUAN) WARNING NR 014//

RMKS/

1. FOR METEOROLOGISTS.

2. 6 HOUR SUMMARY AND ANALYSIS.



SUMMARY:

   INITIAL POSITION: 26.2N 140.7E

   INITIAL INTENSITY: 65 KTS

   GEOGRAPHIC REFERENCE: 548 NM SOUTH OF YOKOSUKA, JAPAN

   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 11 KTS

   SIGNIFICANT WAVE HEIGHT: 28 FEET



SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:

ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON

(TY) 24W (DUJUAN) WITH A PERSISTENT, SMALL CENTRAL DENSE OVERCAST

OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC). A SMALL DIMPLE OF

WARMER CLOUD TEMPERATURES EMBEDDED IN THE CDO HAS APPEARED

INTERMITTENTLY OVER THE PAST SIX HOURS, INDICATING 24W ATTEMPT TO FORM

AN EYE AS IT SLIGHTLY INTENSIFIES. AN 181625Z AMSR3 89 GHZ MICROWAVE

IMAGE DEPICTS A COMPACT RING OF CONVECTION AROUND THE LLCC WITH

SEVERAL BANDS OF CONVECTION WRAPPING IN FROM THE NORTHERN SEMICIRCLE.

THE 37 GHZ IMAGE OF THE SAME PASS SHOWS THE LOWER LEVEL  CENTER IS

VERTICALLY ALIGNED, INDICATING THE SYSTEMS IMPROVED  ORGANIZATION.

ENVIRONMENTAL CONDITIONS ARE ASSESSED TO BE FAVORABLE, WITH LOW (5-10

KTS) OF VERTICAL WIND SHEAR (VWS), WARM (28-29 C) SEA SURFACE

TEMPERATURES, AND GOOD RADIAL OUTFLOW ALOFT. THE INITIAL POSITION IS

PLACED WITH HIGH CONFIDENCE BASED ON EIR AND MICROWAVE IMAGERY. THE

INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE

SPREAD OF AGENCY DVORAK FIXES AND CIMSS OBJECTIVE AIDS LISTED BELOW.



INITIAL WIND RADII BASIS: PERSISTENCE



CURRENT STEERING MECHANISM: WESTERN EXTENSION OF A SUBTROPICAL

RIDGE CENTERED TO THE NORTHEAST



AGENCY DVORAK AND AUTOMATED FIXES:

   PGTW: T4.0 - 65 KTS

   RJTD: T4.0 - 65 KTS

   CIMSS SATCON: 64 KTS AT 181700Z

   CIMSS ADT: 49 KTS AT 181730Z

   CIMSS AIDT: 45 KTS AT 181730Z

   CIMSS D-MINT: 64 KTS AT 181602Z

   CIMSS D-PRINT: 59 KTS AT 181730Z



FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE

   VWS: 5-10 KTS

   SST: 28-29 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: TY 24W IS FORECAST TO CONTINUE ITS NORTHWARD

TRAJECTORY UNDER THE INFLUENCE OF THE WESTERN PERIPHERY OF THE

SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST. AT TAU 24, TY 24W

IS FORECAST TO TURN NORTHWARD AS IT ROUNDS THE AXIS OF THE STR. ONCE

POLEWARD OF THE STR AXIS, 24W WILL ACCELERATE AS IT TRACKS

NORTHEASTWARD FOR THE REMAINDER OF THE FORECAST PERIOD. EXTRATROPICAL

TRANSITION IS EXPECTED TO BEGIN BY TAU 72 AS TY 24W NEARS THE UPPER

LEVEL JET, WITH ETT FORECAST TO COMPLETE BY TAU 96. REGARDING

INTENSITY, TY 24W IS EXPECTED TO REMAIN FAIRLY STEADY OUT TO TAU 60

BEFORE BEGINNING A WEAKENING TREND. THERE IS SOME POSSIBILITY FOR

SMALL, SHORT TERM FLUCTUATIONS IN INTENSITY PRIOR TO THE ONSET OF ETT

AS BRIEF IMPROVED OUTFLOW ALOFT WHILE 24W ROUNDS THE STR AXIS COULD

CAUSE INTENSIFICATION. BY TAU 72, TY 24W WILL CROSS THE 26 C ISOTHERM

AND VWS IS EXPECTED TO INCREASE TO OVER 30 KTS, ENTRAINING LARGE

AMOUNTS OF DRY AIR INTO THE SYSTEM AND CAUSING WEAKENING THEREAFTER,

ALTHOUGH TY 24W IS FORECAST TO REMAIN ABOVE TROPICAL-STORM STRENGTH AS

IT COMPLETES ETT.



MODEL DISCUSSION: TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT FOR THE

REMAINDER OF THE FORECAST PERIOD WITH A CROSS TRACK SPREAD OF 120 NM

AT TAU 96. PAST TAU 72, THERE IS SOME DISAGREEMENT IN THE TRACK SPEED,

WITH AI MODELS DEPICTING A FASTER ACCELERATION ONCE ETT BEGINS. THE

OFFICIAL JTWC FORECAST TRACK IS PLACED WITH HIGH CONFIDENCE, CLOSELY

IN LINE WITH THE MULTI-MODEL CONSENSUS AND GOOGLE DEEPMIND. MODEL

INTENSITY GUIDANCE IS IN GENERAL AGREEMENT OF A STEADY INTENSITY OUT

TO TAU 24 BEFORE THEY DIVERGE, WITH HAFS-A, COAMPS-TC, AND GFS

DEPICTING A BRIEF INTENSIFYING PERIOD BETWEEN TAUS 60 AND 72, LIKELY

DUE TO THE EXPECTED INCREASE IN OUTFLOW ALOFT AT THAT TIME BEFORE ETT

BEGINS. THE OFFICIAL JTWC FORECAST IS ASSESSED WITH MEDIUM CONFIDENCE,

CLOSELY IN LINE WITH GOOGLE DEEPMIND AND SLIGHTLY BELOW THE MULTI-

MODEL CONSENSUS.



FORECAST CONFIDENCE:

   TRACK 00-72 HR: HIGH

   TRACK 72-120 HR: HIGH

   INTENSITY 00-72 HR: MEDIUM

   INTENSITY 72-120 HR: MEDIUM//

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