Advisories

WDPN31 PGTW 172100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (DUJUAN) WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.2N 146.0E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 257 NM EAST OF IWO TO
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 27 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
(TY) 24W (DUJUAN) BECOMING BETTER DEFINED WITHIN A LARGER SURFACE
TROUGH FEATURE, WITH AN IMPROVING CENTRAL DENSE OVERCAST (CDO)
OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC) WITH SOME
CONVECTIVE BANDING BEGINNING TO WRAP ON THE EASTERN FLANK. A
171618Z NOAA-21 89 GHZ MICROWAVE IMAGE DEPICTS THAT THE AREA OF
DEEPEST CONVECTION REMAINS CONFINED TO THE NORTHEASTERN QUADRANT OF
24W. ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE CONDITIONS WITH WARM
(28-29 C) SEA SURFACE TEMPERATURES, LOW (5-10 KTS) VERTICAL WIND
SHEAR (VWS), AND STRONG RADIAL OUTFLOW ALOFT, AS EVIDENCED BY THE
CIRRUS FILAMENTS IN EIR. THE INITIAL POSITION IS PLACED WITH MEDIUM
CONFIDENCE BASED ON THE MICROWAVE AND EIR IMAGERY. THE INITIAL
INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE AS AGENCY DVORAK
FIXES, AST, AIDT, AND DPRINT ARE ON THE LOWER END AS 24W SLOWLY
IMPROVES ITS CONVECTIVE ORGANIZATION BUT LACKS A VISIBLE EYE,
WHEREAS DMINT, MICROWAVE SOUNDERS, AND SATCON ASSESS 24W AS CLOSER
TO TYPHOON STRENGTH.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN EXTENSION OF THE SUBTROPICAL
RIDGE CENTERED FAR TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.0 - 45 KTS
   CIMSS SATCON: 58 KTS AT 171730Z
   CIMSS ADT: 55 KTS AT 171730Z
   CIMSS AIDT: 50 KTS AT 171730Z
   CIMSS D-MINT: 59 KTS AT 171621Z
   CIMSS D-PRINT: 49 KTS AT 171800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TY 24W HAS BEGUN ITS NORTHWESTWARD TURN UNDER
THE STEERING INFLUENCE OF THE WESTWARD EXTENSION OF THE SUBTROPICAL
RIDGE (STR) CENTERED FAR TO THE NORTHEAST. AROUND TAU 24, THIS
EXTENSION IS EXPECTED TO FORM INTO A SEPARATE STR CENTERED CLOSER
TO TY 24W, CAUSING FOR THE SLOW IN TRACK SPEED AND SUBSEQUENT
NORTHWARD TURN AS 24W RECURVES AROUND THE AXIS OF THIS STR. CPA TO
YOKOSUKA IS EXPECTED TO OCCUR AT TAU 72, JUST OFF THE COAST OF
HONSHU. ONCE POLEWARD OF THE STR AXIS, 24W IS FORECAST TO INCREASE
IN TRACK SPEED AND MOVE NORTHEASTWARD FOR THE REMAINDER OF THE
FORECAST PERIOD. REGARDING INTENSITY, TY 24W IS EXPECTED TO
INCREASE GRADUALLY OUT TO A PEAK OF 70 KTS BETWEEN TAUS 36 AND 60
AS OUTFLOW ALOFT IS EXPECTED TO INCREASE NEAR THE AXIS OF THE STR
AND THE REMAINDER OF ENVIRONMENTAL CONDITIONS REMAIN RELATIVELY
FAVORABLE. VWS COULD HAVE SHORT TERM FLUCTUATIONS, ADDING
UNCERTAINTY TO THE INTENSITY FORECAST. TY 24W IS EXPECTED TO BEGIN
WEAKENING BEFORE TAU 72 AS IT ENCOUNTERS INCREASED VWS, COOLER
SSTS, AND BEGINS TO ENTRAIN DRY AIR. EXTRATROPICAL TRANSITION (ETT)
IS EXPECTED TO BEGIN AT TAU 96 AS TY 24W  BEGINS TO INTERACT WITH
STRONG UPPER-LEVEL WESTERLIES. ETT IS EXPECTED TO CONTINUE THROUGH
TAU 120, WHILE REMAINING ABOVE TROPICAL STORM STRENGTH.

MODEL DISCUSSION: MODEL TRACK GUIDANCE REMAINS IN GOOD AGREEMENT
FOR THE REMAINDER OF THE FORECAST PERIOD, ALTHOUGH SEVERAL AIDS
HAVE SHIFTED SLIGHTLY WESTWARD, WITH JGSM, NAVGEM, AND GOOGLE
DEEPMIND NOW DEPICTING BRIEF LANDFALL OVER HONSHU AROUND TAU 72.
HOWEVER, ANALYSIS OF THE ENSEMBLE MODEL GUIDANCE SHOWS THAT THE
LARGE MAJORITY OF MEMBERS FOR ALL PHYSICS-BASED ENSEMBLES AND THE
GOOGLE DEEPMIND FNV-3 DO NOT DEPICT LANDFALL. THUS, THE OFFICIAL JTWC 
FORECAST TRACK IS PLACED WITH HIGH CONFIDENCE, IN GOOD AGREEMENT WITH 
THE MULTI-MODEL CONSENSUS AND AI CONSENSUS. MODEL INTENSITY GUIDANCE 
REMAINS IN MORE DISAGREEMENT, WITH HAFS-A, COAMPS-TC, AND GFS 
CONTINUING TO UNDERESTIMATE THE INTENSITY OF 24W. SEVERAL RAPID 
INTENSIFICATION AIDS HAVE TRIGGERED, AND WHILE NOT REFLECTED IN THE 
OFFICIAL JTWC INTENSITY FORECAST, COULD REMAIN A POSSIBILITY OF 
OCCURRING IN THE NEXT 24 TO 36 HOURS. DUE TO THE LARGER SPREAD OF 
INTENSITY GUIDANCE, THE OFFICIAL JTWC INTENSITY FORECAST IS ASSESSED 
WITH LOW CONFIDENCE, CLOSELY IN LINE WITH THE GOOGLE DEEPMIND AND 
MULTI-MODEL CONSENSUS.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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