WDXS31 PGTW 201500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FINA) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 10.1S 133.3E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 202 NM NORTHEAST OF DARWIN, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 01 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 05S (FINA) CONTINUING TO BE IMPACTED BY NORTHEASTERLY
SHEAR, CAUSING THE DEEP CONVECTION TO BE DISPLACED TO THE
SOUTHWEST. STRONG BURSTS OF CONVECTION THAT ARE CLOSER TO THE
PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) HAVE
RE-EMERGED AROUND 201100Z. A 200941Z WSFM 37 GHZ MICROWAVE IMAGE
REVEALED A COMPACT MICROWAVE EYE FEATURE THAT IS RAGGED ALONG THE
EASTERN SEMICIRCLE. A 200929Z RCM-3 SAR WIND SPEED IMAGE REVEALED A
RING OF 50-55 KTS WITH A VMAX OF 57 KTS IN THE NORTHERN SEMICIRCLE.
THE INITIAL POSITION AND INTENSITY ARE BOTH PLACED WITH MEDIUM
CONFIDENCE BASED ON THE RCM-3 SAR IMAGE. ENVIRONMENTAL ANALYSIS
INDICATES THAT 05S IS IN A MARGINALLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY MODERATE POLEWARD OUTFLOW, MODERATE (15-20 KTS)
NORTHEASTERLY VERTICAL WIND SHEAR, DRY AIR ENTRAINMENT, AND WARM
(29-30 C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: 200929Z RCM-3 SAR DATA

CURRENT STEERING MECHANISM: WEAK STEERING PATTERN WITH A NEAR
EQUATORIAL RIDGE NORTH OF PAPUA NEW GUINEA AND A BUILDING
SUBTROPICAL RIDGE SOUTH OF THE GULF OF CARPENTARIA.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   ADRM: T3.0 - 45 KTS
   CIMSS ADT: 74 KTS AT 201200Z
   CIMSS AIDT: 65 KTS AT 201200Z
   CIMSS D-MINT: 39 KTS AT 200944Z
   CIMSS D-PRINT: 39 KTS AT 201200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR OVER THE EASTERN SEMICIRCLE

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 BEGIN TRACKING
SOUTHWESTWARD, ALONG THE NORTHWESTERN PERIPHERY OF A BUILDING
SUBTROPICAL RIDGE CENTERED SOUTH OF THE GULF OF CARPENTARIA. THIS
SOUTHWESTWARD TRACK IS EXPECTED TO PERSIST THROUGHOUT THE ENTIRE
FORECAST PERIOD. AN INITIAL LANDFALL IS FORECAST TO OCCUR AROUND
TAU 24, NEAR THE GARIG GUNAK BARLU NATIONAL PARK. THE SYSTEM WILL
THEN CROSS THE VAN DIEMEN GULF WITH A SECOND LANDFALL NEAR DARWIN
AS 05S SKIRTS THE COAST. 05S IS THEN EXPECTED TO ENTER THE NORTHERN
PORTION OF THE BONAPARTE GULF NEAR TAU 72 BEFORE MAKING A THIRD
LANDFALL EAST OF KALUMBURU NEAR TAU 96. REGARDING INTENSITY, 05S IS 
FORECAST TO MAINTAIN INTENSITY OVER THE NEXT 12 HOURS AS THE 
NORTHEASTERLY PRESSURE AND DRY AIR CONTINUE TO IMPACT THE VORTEX. 
AFTER TAU 12, 05S IS FORECAST TO MARGINALLY INTENSIFY THROUGH TAU 48 
AS THE SHEAR RELAXES A BIT AND THE SYSTEM BECOMES MORE VERTICALLY 
ALIGNED. MID-LEVEL DRY AIR IS EXPECTED TO CONTINUE TO INHIBIT A 
QUICKER INTENSIFICATION TREND THROUGH THE TIMING OF LANDFALL IN 
DARWIN. SOME SLIGHT WEAKENING AS THE SYSTEM SKIRTS THE COAST IS 
ANTICIPATED FROM TAU 48-60. ONCE THE SYSTEM ENTERS THE BONAPARTE 
GULF, 05S WILL ONCE AGAIN ENCOUNTER INCREASED SHEAR (20-25 KTS), THIS 
TIME FROM THE NORTHWEST. THIS SHEAR, ALONG WITH DRY AIR ENTRAINMENT, 
WILL INHIBIT FURTHER INTENSIFICATION THROUGH THE TIMING OF THE THIRD 
LANDFALL EVENT. AFTER THE THIRD LANDFALL, TERRAIN INTERACTION WILL 
CAUSE 05S TO QUICKLY WEAKEN THROUGH THE REMAINDER OF THE FORECAST 
PERIOD. 05S IS FORECAST TO DISSIPATE OVER LAND NEAR TAU 120 AS THE 
REMNANT VORTEX CONTINUES TO TRACK SOUTHWESTWARD. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 WITH THE EXCEPTION OF GALWEM, WHICH TRACK
THE VORTEX MUCH FURTHER WEST THAN THE REMAINDER OF GUIDANCE.
DISCOUNTING GALWEM, THERE IS A 40 NM CROSS-TRACK SPREAD AT TAU 48,
NEAR THE TIMING OF CPA TO DARWIN, AND A 70 NM CROSS-TRACK SPREAD AT
TAU 72. AFTER TAU 72, MODELS BEGIN TO DIVERGE, PARTICULARLY
INDIVIDUAL GLOBAL ENSEMBLE MEMBERS. THE BULK OF GUIDANCE AGREES ON
A TRACK INLAND AFTER TAU 96, HOWEVER, THE ECMWF DETERMINISTIC
TRACKER TAKES THE SYSTEM WESTWARD, AWAY FROM THE COAST. THE JTWC
TRACK FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS THROUGH
TAU 72 AND THEN CLOSER TO THE GDM AND ECMWF ENSEMBLE MEANS THROUGH
TAU 120. INTENSITY GUIDANCE HAS COME INTO SLIGHTLY BETTER AGREEMENT
BESIDES ONE SIGNIFICANT OUTLIER, HAFS-A. HAFS-A RAPIDLY INTENSIFIES
THE SYSTEM FROM TAU 36 TO TAU 72, REACHING AN UNLIKELY PEAK OF
AROUND 130 KTS AT TAU 72. NORTHWESTERLY SHEAR AND DRY AIR ARE
EXPECTED TO DISALLOW THIS TYPE OF INTENSIFICATION BEFORE THE THIRD
LANDFALL EVENT. DISCOUNTING HAFS-A, MODELS GENERALLY AGREE ON A
STEADY INTENSITY OR MARGINAL INTENSIFICATION THROUGH TAU 72 AND
THEN WEAKENING THEREAFTER. THE JTWC INTENSITY FORECAST IS PLACED
SLIGHTLY HIGHER THAN THE CONSENSUS WITH OVERALL LOW CONFIDENCE. 

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