WDPS31 PGTW 052100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23P (FILI) 
WARNING NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.7S 162.0E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 308 NM NORTHWEST OF NOUMEA, NEW CALEDONI
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE 23P (FILI) MADE THE TURN LAST NIGHT AND IS NOW ON
ITS TERMINAL LEG. VERTICAL WIND SHEAR (VWS) ASSOCIATED WITH
SUBTROPICAL WESTERLIES HAS EASED AS THE STORM'S TRACK SWUNG TO A
LESS PERPENDICULAR DIRECTION. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY REVEALS INCREASING SYMMETRY AND COVERAGE OF THE
DEEP CONVECTION AROUND THE CORE, BUT RECENT FRAMES INDICATE THAT
SOME DRY AIR IS WRAPPING ALL THE WAY AROUND THE EQUATORWARD SIDE
AND PENETRATING TOWARDS THE CORE. WATER VAPOR ANIMATION SHOWS STRONG
RADIAL OUTFLOW AND THE JTWC 1200Z UPPER LEVEL STREAMLINE ANALYSIS
REVEALED AN IDYLLIC POINT SOURCE DIRECTLY ABOVE THE LOW LEVEL
CIRCULATION CENTER. SYSTEM INTENSITY HAS RISEN AS THE VWS EASED AND
NOW FILI IS ENTERING ITS LAST HURRAH BEFORE IT BEGINS THE DECLINE
ASSOCIATED WITH SUBTROPICAL TRANSITION. THE SYSTEM IS CURRENTLY IN
A ZONE OF 27-28C SEA WATERS THAT EXTEND ALONG TRACK ALL THE WAY TO
THE 22ND LATITUDE. BEYOND THAT, SEA SURFACE TEMPERATURES DROP BELOW
SUBSTANTIVE VALUES. THE CURRENT INTENSITY ASSESSMENT AVERAGES THREE
AGENCY SUBJECTIVE DVORAKS AND BALANCES THAT WITH ADT AND SATCON.

INITIAL WIND RADII BASIS: 051128Z METOP-B ASCAT

CURRENT STEERING MECHANISM: AN EXTENSION OF THE SUBTROPICAL RIDGE
EXTENDING OVER THE FIJIAN AND SANTA CRUZ ISLANDS IS BLOCKING
EASTWARD MOVEMENT AND GUIDING THE STORM THROUGH THE SOLOMON SEA.

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   PHFO: T3.5 - 55 KTS
   NFFN: T3.5 – 55 KTS
   CIMSS SATCON: 47 KTS AT 051412Z
   CIMSS ADT: 51 KTS AT 051740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 25-30 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: FILI WILL CONTINUE ITS TRACK THROUGH THE
SOLOMON SEA AND REMAIN WEST OF NEW CALEDONIA, ALTHOUGH WINDFIELDS
WILL IMPACT THE ISLAND AND PILE UP SEAS ALONG THE WEST COAST.
SUSTAINED WARM WATERS AND LOW VWS WILL ONLY LAST THROUGH THE 22ND
LATITUDE, APPROXIMATELY TAU 48. THAT IS WHEN THE SUBTROPICAL
TRANSITION PROCESS WILL BEGIN.  DRY AIR ENTRAINMENT WILL BEGIN
WEAKENING THE CORE AT TAU 48 SIMULTANEOUSLY WITH THE VORTEX
TRACKING OVER UNFAVORABLY COOLER SEA WATERS, AND INCREASING
VERTICAL WIND SHEAR WILL PILE ON ABOUT 12 HOURS AFTER THAT, ALL OF
WHICH WILL COMBINE TO COLLAPSE ANY REMAINING CORE CONVECTION AND
LEAVE THE LLCC COMPLETELY EXPOSED, ALONE AND ADRIFT IN THE SOUTH
PACIFIC BY TAU 72.

MODEL DISCUSSION: AFTER TAU 72, MODEL TRACKERS SCATTER WILLY NILLY
AND SOME LOSE THE VORTEX COMPLETELY, LENDING CONFIDENCE TO THE
SUBTROPICAL TRANSITION SCENARIO. UNTIL THEN, TRACKERS ARE IN DECENT
AGREEMENT WITH THE EXCEPTION OF THE GEFS ENSEMBLE, WHICH MOVES THE
VORTEX MARKEDLY FASTER THAN THE REST OF THE PACK.  THE JTWC TRACK
FORECAST STAYS JUST LEFT OF THE MULTI-MODEL CONSENSUS IN ORDER TO
HEDGE CLOSER TO THE GFS, WHICH HAS BEEN VERY STRONG THIS STORM, AND
AWAY FROM THE NAVGEM AND ECMWF, BOTH OF WHICH LIE RIGHT OF THE
MEAN. IT ALSO PUSHES THE STORM ALONG A LITTLE FASTER THAN CONSENSUS
IN A NOD TO THE AMERICAN ENSEMBLE OUTPUT. THE INTENSITY FORECAST STAYS 
JUST ABOVE THE MEAN DUE TO RECENT AGENCY FIXES COMING IN AT T3.5 AND 
THE PRESENCE OF EXCELLENT CONDITIONS ALONG TRACK OVER THE NEXT 24 HOURS. 
THE TIMING OF SUBTROPICAL TRANSITION IS BASED MOSTLY ON THE HWRF-P 
DEPICTION OF 700-300 HPA RELATIVE HUMIDITIES AND COUPLED SEA SURFACE 
TEMPERATURE OUTPUTS.

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