WDXS31 PGTW 211500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FINA) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.1S 132.2E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 114 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 ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 05S (FINA) WITH A HIGHLY COMPACT CENTRAL DENSE OVERCAST
(CDO) AND CORRESPONDING CLOUD TOPS MEASURING COLDER THAN -80 C
DIRECTLY OVER THE CENTER. THE SYSTEM MADE LANDFALL JUST AFTER
211200Z AND IS CURRENTLY TRACKING OVER THE COBOURG PENINSULA.
210921Z WSFM 37 GHZ MICROWAVE IMAGE REVEALED A SMALL, WELL-DEFINED
MICROWAVE EYE FEATURE WITH TIGHTLY CURVED BANDING WITHIN THE
SOUTHERN SEMICIRCLE. ADDITIONALLY, ANIMATED RADAR IMAGERY FROM
WARRUWI REVEALS A VERY SMALL INNER-CORE, MEASURING ABOUT 30 NM IN
DIAMETER. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON THE ANIMATED RADAR IMAGERY. THE INITIAL INTENSITY OF 70 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK FIXES
AND CIMSS OBJECTIVE ESTIMATES LISTED BELOW. THE COMPACT NATURE OF
THE SYSTEM MAY BE CAUSING DVORAK ANALYSIS TO SLIGHTLY UNDERESTIMATE
INTENSITY. ENVIRONMENTAL ANALYSIS INDICATES THAT 05S IS IN A
FAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG POLEWARD OUTFLOW
ALOFT, LOW (5-10 KTS) DEEP LAYER SHEAR, AMPLE 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: PERSISTENCE WITH SLIGHT ADJUSTMENTS BASED
ON THE OBJECTIVE BEST TRACK

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 ADT: 61 KTS AT 211200Z
   CIMSS AIDT: 67 KTS AT 211200Z
   CIMSS D-MINT: 60 KTS AT 210922Z
   CIMSS D-PRINT: 66 KTS AT 211200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: MODERATE (15-20 KTS) 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 TRAVERSE THE
VAN DIEMEN GULF THROUGH TAU 18 WITH ANOTHER LANDFALL FORECAST TO
OCCUR AT TAU 24, ALONG THE TIP OF THE COX PENINSULA, NEAR DARWIN.
05S IS THEN EXPECTED TO ENTER THE BONAPARTE GULF AROUND TAU 36. A
FINAL LANDFALL IS FORECAST TO OCCUR WITHIN THE NORTHERN KIMBERLEY 
COAST NEAR TAU 72. THE VORTEX IS THEN EXPECTED TO DRIFT FURTHER 
INLAND THROUGH TAU 96 AS IT RAPIDLY WEAKENS. REGARDING INTENSITY, 05S 
IS FORECAST TO STEADILY INTENSIFY OVER THE NEXT 48 HOURS AS THE 
ENVIRONMENT REMAINS OVERALL FAVORABLE WITH LOW SHEAR, AMPLE MOISTURE, 
AND STRONG POLEWARD OUTFLOW. THE VORTEX IS FORECAST TO LARGELY 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. THESE FACTORS ARE EXPECTED TO CAUSE 
05S TO WEAKEN AS IT APPROACHES THE COAST NEAR TAU 72. ONCE 05S MAKES 
ITS FINAL LANDFALL, TERRAIN INTERACTION AND SIGNIFICANT DRY AIR 
ENTRAINMENT WILL CAUSE THE VORTEX TO QUICKLY DETERIORATE WITH 
DISSIPATION FORECAST TO OCCUR AROUND TAU 96. 

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 A 90 NM CROSS-TRACK SPREAD AT TAU
72. AFTER TAU 72, MODELS BEGIN TO DIVERGE WITH SOME MODELS TRACKING
THE SYSTEM MORE 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 110 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 CLOSE TO THE CONSENSUS 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: MEDIUM
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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