WDXS31 PGTW 190300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FINA) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.5S 132.4E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 201 NM NORTH-NORTHEAST OF DARWIN,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 05S (FINA) HAS STEADILY CONSOLIDATED OVER THE
PAST 6 HOURS WITH A GENERAL WARMING TREND OF CONVECTIVE CLOUD TOPS
ON THE WESTERN SIDE OF THE IMPROVING CIRCULATION AND A FRESH BURST
OF CONVECTIVE ACTIVITY WITHIN THE EASTERN SEMICIRCLE AS DEPICTED ON
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY. THE ENVIRONMENT
HAS REMAINED FAVORABLE WITH LITTLE CHANGE IN SUPPORTIVE UPPER-LEVEL
OUTFLOW ALOFT, MODERATE VERTICAL WIND SHEAR (15-20 KTS), AND
CONTINUOUS WARM SEA SURFACE TEMPERATURES (30 C TO 31 C). THE
INITIAL POSITION OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED
ON ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI), EIR SATELLITE
IMAGERY, AND SUBJECTIVE AGENCY FIXES LISTED BELOW. THE INITIAL
INTENSITY OF 50 KTS IS ALSO ASSESSED WITH MEDIUM CONFIDENCE BASED
ON SUBJECTIVE AGENCY ESTIMATES AND UW-CIMSS OBJECTIVE INTENSITY
ESTIMATES RANGING BETWEEN 43-55 KTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: LOW- TO MID-LEVEL NEAR-EQUATORIAL RIDGE
(NER) POSITIONED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   ADRM: T3.0 - 45 KTS
   CIMSS ADT: 55 KTS AT 190100Z
   CIMSS AIDT: 44 KTS AT 190100Z
   CIMSS D-MINT: 43 KTS AT 182128Z
   CIMSS D-PRINT: 41 KTS AT 190100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: WEAK RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE FINA WILL CONTINUE TO TRACK
EAST-NORTHEASTWARD FOR THE NEXT 12 HOURS ALONG THE SOUTHERN
PERIPHERY OF THE NER TO THE NORTH. FOLLOWING TAU 12, COMPETING
STEERING MECHANISMS WILL CAUSE THE SYSTEM TO SLOW IN SPEED OF
APPROACH AND BEGIN ITS INITIAL RECURVE TO THE SOUTHWEST UNTIL TAU
48. BETWEEN TAU 48 AND TAU 60, THE SUBTROPICAL RIDGE TO THE SOUTH
OVER CENTRAL AUSTRALIA WILL BECOME THE PRIMARY STEERING MECHANISM,
CAUSING TC FINA TO BEGIN TRACKING SOUTHWESTWARD THROUGH THE
REMAINDER OF THE FORECAST PERIOD, BRINGING THE CENTER OVER THE
NORTHERN COASTLINES OF THE NORTHERN TERRITORY AND WESTERN
AUSTRALIA. THE ENVIRONMENT WILL REMAIN FAVORABLE FOR STEADY
DEVELOPMENT THROUGH TAU 12. FOLLOWING TAU 12, AN INCREASE IN
VERTICAL WIND SHEAR OF OVER 15 KTS AND DRY AIR ENTRAINMENT WILL
INITIATE A SLOW WEAKENING TREND THROUGH TAU 96. A BRIEF PERIOD OF
REINTENSIFICATION IS FORECASTED BETWEEN TAU 96 AND TAU 120 AS TC FINA
REEMERGES OVER THE TIMOR SEA. DURING THIS PERIOD, WARM SEA SURFACE
TEMPERATURES OF 29-31 C, LOW VERTICAL WIND SHEAR (LESS THAN 15
KTS), AND POLEWARD OUTFLOW WILL ASSIST IN MAINTAINING SURFACE
INTENSITIES NEAR 50 KTS.

MODEL DISCUSSION: MULTI MODEL NUMERICAL PREDICTION GUIDANCE HAS
RETAINED A LARGE CROSS-TRACK SPREAD, UP TO 150 NM AFTER TAU 48,
THOUGH MOST MODELS HAVE SHIFTED TRACKS SLIGHTLY TO THE EAST. GFS
HAS PERSISTED IN ITS DEPICTION OF A SHARPER RECURVE THAT KEEPS THE
SYSTEM IN THE CENTRAL TIMOR SEA. NAVGEM REMAINS THE EASTERNMOST
OUTLIER WHILE ECMWF DEPICTS A TRACK THAT MIRRORS THE MULTI MODEL
CONSENSUS. THE JTWC FORECASTED TRACK REMAINS CLOSE TO THE MULTI
MODEL CONSENSUS THROUGH TAU 60 AND THEN SLIGHTLY TO THE SOUTH OF
THE CONSENSUS FOR THE REMAINDER OF THE FORECAST PERIOD. INTENSITY
SPREAD HAS DECREASED SLIGHTLY TO 40 KTS AND MOST MODEL SOLUTIONS
NOW PORTRAY LOWER MAXIMUM INTENSITIES. THE JTWC OFFICIAL FORECAST
REFLECTS INTENSITIES ALIGNED WITH THE MULTI MODEL CONSENSUS UNTIL
TAU 120.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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