WDPS31 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23P (FILI) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.7S 163.7E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 158 NM WEST-NORTHWEST OF NOUMEA, NEW
CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
MEDIUM-SIZED SYSTEM THAT HAS MOSTLY MAINTAINED A NW-SE ELONGATED
SHAPE DUE TO NORTHWESTERLY SHEAR. ALTHOUGH THE CENTRAL DEEP OVERCAST 
HAS RECENTLY FLARED AND EXPANDED, THE EIR LOOP ALSO SHOWS UNRAVELING 
AND FRAGMENTATION OF THE FEEDER BANDS, ESPECIALLY ALONG THE SOUTHERN 
FLANK WHERE THE VWS IS STRONGER. THE INITIAL POSITION AND INTENSITY 
ARE PLACED WITH HIGH CONFIDENCE BASED ON A TIGHT CIRCULATION IN THE 
061107Z ASCAT BULLSEYE PASS THAT SHOWS 55-KT WIND BARBS ALONG THREE 
SECTORS WITHIN 25NM. THE INITIAL INTENSITY IS ALSO SUPPORTED BY AN 
OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES (SEE 
BELOW). ANALYSIS INDICATES A MARGINALLY UNFAVORABLE ENVIRONMENT WITH
STRONG POLEWARD OUTFLOW AND WARM SST OFFSET BY MODERATE VWS - 
TEMPERED BY THE STORM MOTION THAT IS IN PHASE WITH UPPER LEVEL WIND 
FLOW - AND DRY AIR INTRUSION IN THE LOW LEVELS. THE CYCLONE IS 
TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE STR TO THE 
NORTHEAST.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   PHFO: T4.0 - 65 KTS
   CIMSS SATCON: 60 KTS AT 061057Z
   CIMSS ADT: 41 KTS AT 061140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC FILI WILL CONTINUE ON A GENERALLY
SOUTHEASTWARD TRACK UNDER THE STEERING INFLUENCE OF THE STR. THE
MARGINALLY UNFAVORABLE ENVIRONMENT WILL BECOME MORE UNFAVORABLE AS
VWS INCREASES (30KTS+) AND, BY TAU 24, SST BECOMES COLDER (26C). AS A
RESULT, TC 23P WILL WEAKEN TO 40KTS BY TAU 36. CONCURRENTLY BY TAU 
24, TC 23P WILL BEGIN SUBTROPICAL TRANSITION AND BY TAU 36, WILL 
TRANSFORM INTO A SUBTROPICAL SYSTEM. THERE IS, HOWEVER, A DISTINCT 
POSSIBILITY THAT THE SYSTEM WILL DISSIPATE BEFORE BECOMING 
SUBTROPICAL DUE TO INCREASINGLY HARSH ENVIRONMENT AS THE CYCLONE 
MOVES FURTHER POLEWARD.


MODEL DISCUSSION: NUMERICAL MODELS ARE IN GENERALLY TIGHT AGREEMENT
WITH THE SOUTHEASTWARD TRACK UP TO TAU 24. AFTERWARD, THE MEMBERS
FAN OUT SIGNIFICANTLY TO OVER 400NM BY TAU 36 - AN INDICATION OF A
WEAK VORTEX. GFS IS THE RIGHT-OF-TRACK OUTLIER AND UKMET IS ON THE
LEFT MARGIN OF THE MODEL ENVELOPE. OVERALL, THERE IS MEDIUM
CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID CLOSE TO THE
MODEL CONSENSUS. 

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