WDPS31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23P (FILI) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.5S 162.3E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 264 NM NORTHWEST OF NOUMEA, NEW CALEDONIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
JUST WHEN THE PARTY WAS GETTING GOING AND TROPICAL CYCLONE FILI
CROSSED 55KTS AND DEVELOPED A BROAD AND SYMMETRIC FIELD OF DEEP
CONVECTION, A TREMENDOUS AMOUNT OF DRY AIR ADVECTION SHOWED UP
PREMATURELY AND CRASHED THE PARTY. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) SHOWS THAT A TONGUE OF DRY AIR FROM THE WESTERN SIDE
OF THE SOUTH PACIFIC CONVERGENCE ZONE WRAPPED AROUND THE
EQUATORWARD SEMICIRCLE AND MADE IT ALL THE WAY INTO THE CORE. THE
LOW LEVEL CIRCULATION IS BECOMING ISOLATED AND CHOKED OFF AND ADT
RAW VALUES ARE FALLING PRECIPITOUSLY. FILI HAD ANOTHER 24 HOURS OF
FAVORABLE ENVIRONMENTAL CONDITIONS AHEAD BUT NOW IT LOOKS LIKE THE
SYSTEM HAS TOPPED OUT. A 052151Z PASS DOES CONFIRM GALE FORCE WINDS
HAD REACHED THE NORTHERN TIP OF NEW CALEDONIA AND ON THE SYNOPTIC
HOUR THE SUBJECTIVE DVORAKS WERE ALL IN THE 3.5 TO 4.0 RANGE, WITH
SATCON AND ADT BOTH ASSESSING NEARLY 60KTS. IT WAS ALMOST
IMMEDIATELY AFTER THAT WHEN THE DRY AIR KICKED DOWN THE DOOR, SO
THE CURRENT INTENSITY REFLECTS THE LOWEST OF THE ASSESSMENTS, T3.5
FROM BOTH KNES AND PGTW. TC 28P IS TRACKING THROUGH THE LAST OF THE
28C SEA WATERS AND BEGINNING TO NEAR 26C BY TAU 24. VERTICAL WIND
SHEAR HAS EASED TO BELOW 20KTS AND ANIMATED WATER VAPOR IMAGERY
SHOWS ROBUST OUTFLOW OVER THE NORTHEAST AND SOUTHEAST QUADRANTS.

INITIAL WIND RADII BASIS: PERSISTENCE FROM A 051128Z METOP-B ASCAT
PASS. 

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: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   PHFO: T4.0 - 65 KTS
   CIMSS SATCON: 58 KTS AT 052012Z
   CIMSS ADT: 59 KTS AT 052340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 12-18 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG EASTWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT IS ERODING THE CORE OF THE
SYSTEM. 

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST HAS BEEN UPDATED TO AN
EARLIER TIME OF PEAK INTENSITY AND LOWER VALUE OF THAT PEAK. 

FORECAST DISCUSSION: TROPICAL CYCLONE FILI WILL CONTINUE FIGHTING
THE EFFECTS OF DRY AIR ENTRAINMENT WHILE REMAINING ON ITS
SOUTHEASTWARD AND TERMINAL LEG. IT WILL BENEFIT FROM ANOTHER OF 12
TO 18 HOURS OF LOW VERTICAL WIND SHEAR BUT AT THE SAME TIME WILL BE
TRACKING INTO A REGION OF SLOWLY COOLING SEA WATERS. THE SEA
SURFACE TEMPERATURE WILL BE NEAR 26C BY AU 36.  STEADY STEERING
FLOW WILL KEEP THE SYSTEM TO THE WEST OF NEW CALEDONIA BUT THE
PROXIMITY OF THE SYSTEM TO THE ISLAND WILL DRAW NEAR GALE TO GALE
FORCE EASTERLIES OVER THE ISLAND AND PILE UP SEAS ALONG THE EAST
COAST.  BY TAU 36 THE SUBTROPICAL TRANSITION PROCESS WILL BE WELL
UNDERWAY AND BY TAU 72 AT THE LATEST, THE VORTEX WILL BE COMPLETELY
DEVOID OF CONVECTION AND MEANDERING IN THE SOUTH PACIFIC. DURING
THAT TIME A MIGRATORY HIGH PRESSURE SYSTEM MOVING THROUGH THE
TASMAN SEA WILL DRIVE EASTERLIES ALONG THE POLEWARD SIDE OF THE
SYSTEM AND THE INDUCED VORTICITY WILL SUSTAIN THE REMNANT VORTEX.  


MODEL DISCUSSION: MODEL GUIDANCE SPREAD RATHER THAN FOCUSED DURING
THE LAST RUN BUT THEY ALL TELL THE SAME STORY.  SPEED OF ADVANCE IS
CONSISTENT BUT THERE IS MORE EAST TO WEST SPREAD BETWEEN THE
MODELS. THE EUROPEAN PACKAGE IS THE MOST WESTWARD WHILE THE NAVGEM
AND AFUM ARE THE FURTHEST EASTWARD. THE JTWC TRACK FORECAST STAYS
TO THE EAST OF THE MEAN AND CLOSER TO THE GFS BASED ON THE GFS
PERFORMANCE OVER THE PAST SEVERAL DAYS, WHICH PUTS THE TRACK A
LITTLE CLOSER TO NEW CALEDONIA. INTENSITY GUIDANCE IS FLAT THROUGH
24 HOURS THEN BEGINS A STEADY DECLINE AND THAT IS REFLECTED IN THE
JTWC FORECAST, ALTHOUGH THE JTWC FORECAST IS ANOTHER 5 KNOTS BELOW
THE MEAN.  

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