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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