WDPN32 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (KHANUN) WARNING NR 
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.6N 133.0E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 592 NM SOUTH-SOUTHEAST OF KADENA AB,
OKINAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A
MEDIUM-SIZED SYSTEM THAT CONTINUED TO CONSOLIDATE AS THE CENTRAL
DENSE OVERCAST (CDO) BECAME MORE ORGANIZED AND SYMMETRICAL. A DRY
SLOT WRAPPING IN FROM THE NORTHWEST REMAINS; HOWEVER, RAIN BANDS,
ALBEIT FRAGMENTED AND TRAILING SOUTHWESTWARD ARE FEEDING PERSISTENTLY 
INTO THE CDO. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE 
USING CLOUD MINIMUM WEDGE - CLOUD COMMA INTERPOLATIONS FROM THE 
291800 EIR IMAGE AND FROM RECENT ATMS MICROWAVE IMAGES. THE
INITIAL INTENSITY OF 55KTS IS ALSO PLACED WITH MEDIUM CONFIDENCE
BASED ON THE PGTW, KNES, SATCON, AND D-PRINT DVORAK ESTIMATES.
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW VWS, STRONG
COMBINED OUTFLOW, AND WARM SST TEMPERED BY THE DRY AIR INTRUSION.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

CURRENT STEERING MECHANISM: NEAR EQUATORIAL RIDGE (NER) TO THE EAST
WITH N-S AXIS LINED OVER GUAM. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 56 KTS AT 291635Z
   CIMSS D-PRINT: 53 KTS AT 291900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: WEAK POLEWARD OUTFLOW CHANNEL INTO A TUTT CELL TO
THE NORTH.

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: TS KHANUN WILL CONTINUE ON A
NORTH-NORTHWESTWARD TRACK UNDER THE STEERING INFLUENCE OF THE NER.
AFTER TAU 36, A SUBTROPICAL RIDGE (STR) TO THE NORTH WILL ASSUME
STEERING AND DRIVE THE SYSTEM ON A MORE NORTHWESTWARD TRAJECTORY 
TOWARD OKINAWA, PASSING APPROXIMATELY 60 NM SOUTHWEST OF THE ISLAND 
JUST AFTER TAU 48 PRIOR TO DRIFTING INTO THE EAST CHINA SEA AND 
MAKING LANDFALL SOUTH OF SHANGHAI AROUND TAU 96. THE MARGINALLY 
FAVORABLE ENVIRONMENT WILL FUEL A GRADUAL INTENSIFICATION AIDED BY 
INCREASING POLEWARD OUTFLOW AS THE STEERING MECHANISM SWITCHES TO THE 
STR TO A PEAK OF 95KTS BY TAU 72. AFTER TAU 72, SUBSIDENCE CAUSED BY 
A PASSING MID-LATITUDE TROUGH TO THE NORTH WILL WEAKEN 06W TO 65 KTS 
AT LANDFALL. AFTER LANDFALL, INTERACTION WITH THE RUGGED CHINESE 
INTERIOR WILL MOSTLY BE RESPONSIBLE FOR THE RAPID EROSION, AND BY TAU 
120, TC 06W WILL BE REDUCED TO 40 KTS, POSSIBLY WEAKER, AS IT TRACKS 
FURTHER INLAND.


MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY GOOD AGREEMENT WITH
A GRADUAL SPREAD TO A MERE 113 NM BY TAU 72 THEN TO 485 NM BY TAU
120. IN VIEW OF THIS, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK THAT IS LAID JUST TO THE RIGHT OF THE MODEL CONSENSUS TO
OFFSET UKMET UP TO TAU 72 THEN MEDIUM CONFIDENCE AFTERWARD. 


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