WDXS31 PGTW 200900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FINA) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 10.0S 133.3E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 206 NM NORTHEAST OF DARWIN, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 05S (FINA) WITH WARMING CLOUD TOPS AND NORTHEASTERLY
PRESSURE CAUSING THE LOW-LEVEL CIRCULATION CENTER (LLCC) TO BECOME
SLIGHTLY EXPOSED. A 200438Z AMSR2 89 GHZ MICROWAVE IMAGE REVEALED A
DEFINED CENTER WITH DEEP CONVECTION SHEARED OFF TO THE WEST. THE
INITAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON
EXTRAPOLATION FROM THE CENTER APPARENT IN THE AMSR2 IMAGE. THE
INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH LOW CONFIDENCE DUE TO
THE WIDE RANGE IN INTENSITY ESTIMATES RANGING FROM 49-79 KTS. THE
INITIAL INTENSITY ASSESSMENT IS PLACED CLOSER TO THE CIMSS SATCON AND
SUBJECTIVE AGENCY DVORAK ESTIMATES. ENVIRONMENTAL ANALYSIS
INDICATES THAT 05S IS IN A MARGINALLY FAVORABLE ENVIRONMENT
CHARACTERIZED BY MODERATE OUTFLOW, MODERATE NORTHEASTERLY VERTICAL
WIND SHEAR, DRY AIR ENTRAINMENT, AND WARM (29-30 C) SEA SURFACE
TEMPERATURES.

INITIAL WIND RADII BASIS: 200033Z METOP-B SCATTEROMETER DATA

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A NEAR
EQUATORIAL RIDGE CENTERED NORTHEAST OF PAPUA NEW GUINEA.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   ADRM: T3.5 - 55 KTS
   CIMSS SATCON: 62 KTS AT 200600Z
   CIMSS ADT: 79 KTS AT 200600Z
   CIMSS AIDT: 72 KTS AT 200600Z
   CIMSS D-MINT: 49 KTS AT 200438Z
   CIMSS D-PRINT: 49 KTS AT 200600Z

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

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

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
30, NEAR THE GARIG GUNAK BARLU NATIONAL PARK. THE SYSTEM WILL THEN
CROSS THE VAN DIEMEN GULF AND A SECOND LANDFALL IS FORECAST 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 JUST AFTER TAU 96. REGARDING
INTENSITY, 05S IS FORECAST TO MAINTAIN INTENSITY OF 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 NORTHEASTERLY 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 BRIEF 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 WILL INHIBIT INTENSIFICATION THROUGH THE TIMING OF THE THIRD
LANDFALL EVENT. AFTER THE THIRD LANDFALL, TERRAIN INTERACTION WILL
CAUSE 05S TO QUICKLY WEAKEN THROUGH THE END OF THE FORECAST PERIOD.


MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 WITH A 90 NM CROSS-TRACK SPREAD AT TAU 72.
AFTER TAU 72, MODELS BEGIN TO DIVERGE, PARTICULARLY WITHIN THE
GLOBAL ENSEMBLES. CROSS-TRACK SPREAD BETWEEN CONSENSUS MEMBERS
INCREASES TO 210 NM AT TAU 120 WITH NAVGEM MAKING UP THE
SOUTHERNMOST MODEL WHILE GALWEM MAKES UP THE NORTHERNMOST. THE JTWC
TRACK FORECAST IS PLACED CLOSE TO THE CONSENSUS THROUGH TAU 72 AND
THEN CLOSER TO THE GDM AND ECMWF ENSEMBLE MEANS THROUGH TAU 120.
INTENSITY GUIDANCE IS IN POOR AGREEMENT WITH MODELS SPLIT BETWEEN
INTENSIFICATION AND WEAKENING THROUGH TAU 48. HAFS-A IS A
SIGNIFICANT OUTLIER, SUGGESTING RAPID INTENSIFICATION AFTER TAU 48
TO A PEAK OF AROUND 120 KTS. HAFS-A DOES TRACK THE VORTEX FURTHER
FROM THE COAST, CAUSING THERE TO BE SIGNIFICANTLY LESS LAND
INTERACTION THAN THE JTWC FORECAST CALLS FOR. THE AMOUNT OF LAND
INTERACTION WILL GREATLY AFFECT THE INTENSITY OF 05S AND CAUSES
THERE TO BE LOW CONFIDENCE IN THE JTWC INTENSITY FORECAST. 

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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