WDPN31 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (IN-FA) WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.1N 128.2E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 146 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) CONFIRMS THAT TY 09W
IS SUCCESSFULLY COCOONING ITSELF FROM A BROAD STREAM OF DRY AIR AND
MAINTAINING CORE INTEGRITY. THE DRY NORTHERLIES ARE ASSOCIATED WITH A
RIDGE BUILDING OVER EASTERN CHINA AND ALTHOUGH THEY HAVE BEEN
DIVING OVER THE EAST CHINA SEA AND WRAPPING AROUND THE SYSTEM FOR
OVER 24 HOURS, THE SYSTEM HAS BEEN ABLE TO KEEP A MOIST LAYER
AROUND THE CORE AND MAINTAIN A STEADY INTENSITY. THE STORM
HAS PASSED ITS CLOSEST POINT OF APPROACH TO OKINAWA AND IS OPENING
ALONG A STEADY TRACK TO THE WEST-SOUTHWEST AS A STRONG UPPER LEVEL 
HIGH HEIGHT CENTER ANCHORS ITSELF OVER THE SEA OF JAPAN AND BUILDS 
INTO THE PHILIPPINE SEA. AN EYE FIX ALLOWS FOR GOOD CONFIDENCE ON THE
POSITION AND IDENTICAL DVORAK ASSESSMENTS FROM BOTH PGTW AND RJTD
ALLOW FOR GOOD CONFIDENCE IN THE INTENSITY.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: THE SUBTROPICAL RIDGE ANCHORED OVER THE
SEA OF JAPAN. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   KNES: T5.0 - 90 KTS
   CIMSS ADT: 102 KTS AT 201740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: THE SUBSTANTIAL AMOUNT OF DRY AIR ENTRAINMENT ON
THE EQUATORWARD SIDE IS COMPLETELY SUPPRESSING OUTFLOW ON THE
SOUTHERN SIDE OF THE SYSTEM AND THE SLOW MOVEMENT OF THE STORM IS
CHURNING UP COOLER WATERS, KEEPING INTENSIFICATION LIMITED TO A
LOWER THAN CLIMATOLOGICAL RATE. 

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: THE BUILDING SUBTROPICAL RIDGE WILL STEER
TYPHOON 09W STEADILY TO TO THE WEST-SOUTHWEST OVER THE NEXT 48
HOURS, UNTIL IT WEAKENS AND RETROGRADES TO ALONG THE CONTINENTAL
COAST. AS IT DOES SO, IT WILL ALLOW THE STORM TO LIFT TO A MORE
POLEWARD TRACK JUST AS IT IS APPROACHING THE SOUTHERNMOST SENKAKUS.
THE RIDGE OVER EASTERN CHINA THAT IS SHOOTING THE DRY AIR INTO THE
SYSTEM WILL WEAKEN AT ABOUT THE SAME TIME AND TY 09W WILL PEAK IN
INTENSITY JUST AS IT BEGINS TO TRACK NORTH OF WEST. AS IT MOVES
INTO THE NORTHWESTERLY TRACK, IT WILL WEAKEN SLOWLY OVER THE EAST 
CHINA SEA UNTIL IT MAKES LANDFALL AT OR JUST BELOW TYPHOON 
INTENSITY. 

MODEL DISCUSSION: MODEL GUIDANCE HAS BEEN CONSISTENT THROUGHOUT THE
STORMS LIFE CYCLE UP TO THE 72 HOUR PERIOD, THEN SCATTERING TO AS
FAR SOUTH AS A STRIKE ON TAIPEI (AFUM AND EGRR) AND AS FAR NORTH AS
THE 28TH LATITUDE. THE ECMWF ENSEMBLE HAS BEEN STEADY AND IS
CONSISTENT WITH CONSENSUS, WHILE THE GFS ENSEMBLE HAS SHOWN A
TREMENDOUS VARIABILITY IN THE LATER TAUS. BASED ON THE EXCELLENT
PERFORMANCE OF THE MULT-MODEL CONSENSUS THUS FAR, THE JTWC FORECAST
STAYS CLOSE TO CONSENSUS THROUGHOUT THE FORECAST. 

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