WDXS31 PGTW 210900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FINA) WARNING NR 
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 10.7S 132.4E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 139 NM NORTHEAST OF DARWIN, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 05S (FINA) WITH VIGOROUS BURSTS OF DEEP CONVECTION
OBSCURING THE COMPACT LOW-LEVEL CIRCULATION CENTER (LLCC). 05S IS
ANALYZED TO HAVE INITIATED ITS SOUTHWESTWARD TRACK OVER THE PAST 6
HOURS. ANIMATED RADAR IMAGERY FROM WARRUWI SHOWS THE SYSTEM HAS
FORMED A WELL-DEFINED INNER CORE WITH SPIRAL RAINBANDS WRAPPING
INTO THE CENTER. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE ANIMATED RADAR IMAGERY. THE INITIAL
INTENSITY OF 65 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
AGENCY DVORAK AND CIMSS OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.
ENVIRONMENTAL ANALYSIS INDICATES THAT 05S IS NOW IN A FAVORABLE
ENVIRONMENT CHARACTERIZED BY MODERATE POLEWARD AND EQUATORWARD
OUTFLOW ALOFT, LOW (5-10 KTS) DEEP-LAYER VERTICAL WIND SHEAR,
SUFFICIENT MID-LEVEL MOISTURE, AND VERY WARM (30-31 C) SEA SURFACE
TEMPERATURES. THE ONLY NEGATIVE FACTOR REMAINS SOME MODERATE (15-20
KTS) NORTHERLY MID-LEVEL SHEAR ACTING ON THE VORTEX.

INITIAL WIND RADII BASIS: 210056Z METOP-C SCATTEROMETER DATA

CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE CENTERED SOUTH OF THE GULF OF CARPENTARIA

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   ADRM: T3.5 - 55 KTS
   CIMSS SATCON: 58 KTS AT 210459Z
   CIMSS ADT: 61 KTS AT 210600Z
   CIMSS AIDT: 67 KTS AT 210600Z
   CIMSS D-MINT: 54 KTS AT 210459Z
   CIMSS D-PRINT: 54 KTS AT 210630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: MODERATE NORTHERLY MID-LEVEL SHEAR 

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 05S IS FORECAST TO CONTINUE TRACKING
SOUTHWESTWARD, ALONG THE NORTHWESTERN PERIPHERY OF THE SUBTROPICAL
RIDGE CENTERED SOUTH OF THE GULF OF CARPENTARIA THROUGHOUT THE
ENTIRETY OF THE FORECAST PERIOD. 05S IS FORECAST TO MAKE AN INITIAL
LANDFALL ALONG THE WESTERN EDGE OF THE GARIG GUNAK BARLU NATIONAL
PARK AROUND TAU 12 BEFORE ENTERING THE VAN DIEMEN GULF. 05S WILL
THEN TRACK THROUGH THE CLARENCE STRAIT AND SKIRT THE COAST THROUGH
TAU 36, PASSING JUST OFF THE COAST OF DARWIN NEAR TAU 30. 05S IS
THEN EXPECTED TO ENTER THE NORTHERN PORTION OF THE BONAPARTE GULF
AROUND TAU 48. A FINAL LANDFALL IS FORECAST TO OCCUR WITHIN THE
NORTHERN KIMBERLEY COAST JUST AFTER TAU 72. REGARDING INTENSITY,
05S IS FORECAST TO STEADILY INTENSIFY OVER THE NEXT 48 HOURS AS THE
ENVIRONMENT REMAINS OVERALL FAVORABLE WITH LOW SHEAR AND A MOIST
ENVIRONMENT. THE VORTEX IS FORECAST TO REMAIN OFF THE COAST,
LIMITING FRICTIONAL EFFECTS, AND ALLOWING 05S TO TAKE ADVANTAGE OF
THE VERY WARM SEA SURFACE TEMPERATURES IN THE AREA. AFTER TAU 48,
NORTHWESTERLY SHEAR INCREASES TO AROUND 20 KTS AND DRY AIR BEGINS
TO IMPACT THE VORTEX. THIS IS EXPECTED TO CAUSE 05S TO WEAKEN AS IT
APPROACHES THE COAST NEAR TAU 72. ONCE 05S MAKES ITS FINAL
LANDFALL, TERRAIN INTERACTION WILL CAUSE THE VORTEX TO QUICKLY
DETERIORATE WITH DISSIPATION FORECAST TO OCCUR AROUND TAU 120. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 WITH THE EXCEPTION OF GALWEM, WHICH TRACKS
THE VORTEX MUCH FURTHER WEST THAN THE REMAINDER OF GUIDANCE.
DISCOUNTING THE OUTLIER, THERE IS AN 85 NM CROSS-TRACK SPREAD AT
TAU 72. AFTER TAU 72, MODELS BEGIN TO DIVERGE WITH SOME MODELS
TRACKING THE SYSTEM WESTWARD, ALONG THE COAST (GFS AND ECMEF) WHILE
OTHERS CONTINUE TO DRIVE THE VORTEX SOUTHWESTWARD (GDM AND
EC-AIFS). THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS THROUGH TAU 72 AND CLOSER TO THE GDM ENSEMBLE
MEAN THEREAFTER. INTENSITY GUIDANCE CONTINUES TO HAVE A SIGNIFICANT
OUTLIER IN HAFS-A, WHICH PEAKS THE SYSTEM AT 130 KTS AT TAU 60. THE
REMAINDER OF GUIDANCE SUGGESTS A RANGE BETWEEN MARGINAL
INTENSIFICATION AND MARGINAL WEAKENING THROUGH TAU 72. THE JTWC
INTENSITY FORECAST IS PLACED SLIGHTLY HIGHER THAN THE BULK OF
GUIDANCE WITH OVERALL LOW CONFIDENCE. SMALL ADJUSTMENTS IN THE
TRACK COULD RESULT IN LARGE CHANGES TO THE INTENSITY FORECAST
DEPENDING ON THE PROXIMITY TO LAND.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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