WDPN31 PGTW 211500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (IN-FA) WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.9N 126.7E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 161 NM SOUTH-SOUTHWEST OF KADENA AIR BASE
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAGGED
EYE WITH AN EYEWALL THAT CONTINUES TO DISPLAY GAPS, PARTICULARLY TO
THE EAST AND NORTH. RADAR IMAGERY FROM JAPAN ALSO SHOWS A
CONCENTRIC BAND FORMING OUTSIDE OF THE EYEWALL AT A 40-45 NM
RADIUS, ENCIRCLING ABOUT 75 PERCENT OF THE CORE. WATER VAPOR
SATELLITE IMAGERY CONTINUES TO INDICATE DRY AIR WRAPPING AROUND THE
CIRCULATION AND GETTING INGESTED INTO THE EASTERN SIDE OF THE INNER
CORE, LIKELY CONTRIBUTING TO THE RAGGED CONVECTIVE STRUCTURE.
COUPLED OCEAN ANALYSES FROM HWRF AND COAMPS-TC SHOW THAT THE
TYPHOON'S SLOW FORWARD MOTION HAS LIKELY RESULTED IN COOLING SEA
SURFACE TEMPERATURES BENEATH THE INNER CORE, CREATING ANOTHER
LIMITATION ON INTENSITY. THE INITIAL INTENSITY IS HELD AT 95 KT
BASED ON A BLEND OF OBJECTIVE DVORAK INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: 211101 METOP-A SCATTEROMETER DATA

CURRENT STEERING MECHANISM: LOW TO MID-LEVEL RIDGE OVER THE SEA OF
JAPAN

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   CIMSS ADT: 104 KTS AT 211130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: DRY AIR WRAPPING INWARD FROM WESTERN SEMICIRCLE
INTO THE SOUTHERN AND EASTERN SEMICIRCLES

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: TYPHOON 09W (IN-FA) HAS TAKEN A JOG
SOUTHWESTWARD DURING THE PAST SIX HOURS, BUT IS EXPECTED TO SOON
RESUME A MORE WESTWARD MOTION FOR THE NEXT 24-36 HOURS AS THE
TYPHOON IS NUDGED ALONG BY A LOW-MID LEVEL RIDGE ANCHORED OVER THE
SEA OF JAPAN. A TURN TO THE NORTHWEST ACROSS THE EAST CHINA SEA IS
EXPECTED AFTER 36 HOURS AS THE TYPHOON ROUNDS THE SOUTHWESTERN 
PERIPHERY OF THE RIDGE AND AN UPPER-LEVEL TROUGH DIGS OVER EASTERN 
CHINA. THE NORTHWESTWARD TRACK IS EXPECTED TO CARRY TYPHOON IN-FA 
INTO EASTERN CHINA BETWEEN 72 AND 96 HOURS TO THE SOUTH OF SHANGHAI. 
NUMERICAL MODEL GUIDANCE CONTINUES TO GRADUALLY SHIFT TO THE RIGHT 
TODAY, AND THE JTWC TRACK FORECAST HAS BEEN SHIFTED UP TO 20 NM TO 
THE RIGHT OF THE PREVIOUS FORECAST AFTER 36 HOURS. STEERING CURRENTS 
ARE FORECAST TO WEAKEN AFTER 72 HOURS AS THE RIDGE OVER THE SEA OF 
JAPAN WEAKENS AND SHIFTS EASTWARD. IF THIS HAPPENS MORE QUICKLY THAN 
FORECAST, THERE EXISTS POTENTIAL FOR TYPHOON IN-FA TO SLOW DOWN AND 
REMAIN OFFSHORE OF CHINA WHILE TURNING NORTHWARD AFTER 72 HOURS, AS 
DEPICTED BY THE GFS ENSEMBLE AND HWRF. THE CURRENT JTWC FORECAST 
STAYS CLOSER TO THE MULTI-MODEL CONSENSUS OVER EASTERN CHINA, WITH 
LOWER THAN AVERAGE CONFIDENCE. REGARDING THE INTENSITY FORECAST, THE 
TYPHOON IS CURRENTLY BEING LIMITED BY DRY AIR ENTRAINMENT AND THE 
LIKELIHOOD OF SOME DYNAMIC OCEAN COOLING BENEATH THE CIRCULATION, AS 
INDICATED BY COUPLED OCEAN ANALYSES FROM THE HWRF AND COAMPS-TC 
MODELS. OCEAN ANALYSIS INDICATES THAT TYPHOON IN-FA IS CURRENTLY 
MOVING OUT OF A COOL EDDY LOCATED SOUTH OF OKINAWA, AND WILL MOVE 
OVER A DEEPER LAYER OF WARM WATER DURING THE NEXT 24-36 HOURS. THE 
JTWC INTENSITY FORECAST THUS CALLS FOR SLIGHT INTENSIFICATION DURING 
THE NEXT 24-36 HOURS TO A PEAK INTENSITY OF 100 KT. THEREAFTER, 
PROXIMITY TO TAIWAN IS EXPECTED TO DISRUPT THE MONSOONAL INFLOW 
CHANNEL, WHICH COMBINED WITH SHALLOWER WARM WATER IN THE EAST CHINA 
SEA, IS EXPECTED TO INDUCE GRADUAL WEAKENING AS TYPHOON 09W 
APPROACHES CHINA.

MODEL DISCUSSION: THE JTWC TRACK FORECAST LIES CLOSE TO THE
MULTI-MODEL CONSENSUS, BUT A LITTLE SLOWER AFTER 72 HOURS. THE
INTENSITY FORECAST IS SLIGHTLY ABOVE THE MULTI-MODEL CONSENSUS
DURING THE FIRST 48 HOURS.

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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