WDPS32 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06P (TIFFANY) WARNING 
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.9S 146.7E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 187 NM NORTH-NORTHEAST OF CAIRNS,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE 06P (TIFFANY) IS A COMPACT SYSTEM, WHICH HAS
RAPIDLY CONSOLIDATED AND INTENSIFIED OVER THE PREVIOUS 12 HOURS.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPACT
AREA OF INTENSE DEEP CONVECTION THAT HAS DEVELOPED OVER OR NEAR THE
ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). A 090406Z AMSR2
COLORIZED 37GHZ MICROWAVE IMAGE INDICATED WELL DEFINED SPIRAL BANDS
OF CONVECTION WRAPPING INTO A NASCENT MICROWAVE EYE FEATURE. WHILE
ON THE VERY EDGE OF THE CAIRNS RADAR, THE LATEST DATA SHOWS WHAT
COULD BE THE FIRST HINTS OF THE INNER CORE OF THE SYSTEM. WHILE THE
CIMSS VERTICAL WIND SHEAR ANALYSIS SUGGESTS 25-30 KNOTS OF SHEAR,
PGTW HAND ANALYSIS OF THE UPPER-LEVEL WINDS SUGGESTS THAT A VERY
SMALL POINT SOURCE OR ANTICYCLONE HAS DEVELOPED OVER TOP OF THE
LLCC. THE RAPID DEVELOPMENT OF SYMMETRICAL CORE CONVECTION WOULD
SUGGEST THAT THE ACTUAL SHEAR VALUES ARE A BIT LOWER THAN THE
AUTOMATED ANALYSIS WOULD SUGGEST. THE INITIAL POSITION IS ASSESSED
WITH HIGH CONFIDENCE BASED ON AN EXTRAPOLATION OF THE MICROWAVE
CENTER IN THE AMSR2 IMAGERY, AGENCY FIX POSITIONS AND THE ANIMATED
RADAR DATA. THE INITIAL INTENSITY OF 35 KNOTS IS ASSESSED WITH
MEDIUM CONFIDENCE, IN LINE WITH THE PGTW AND KNES T2.5, BUT
SLIGHTLY LOWER THAN THE ABRF T3.0 ESTIMATE.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF A DEEP
SUBTROPICAL RIDGE (STR) CENTERED OVER CENTRAL AUSTRALIA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   ABRF: T3.0 - 45 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TROPICAL CYCLONE TIFFANY HAS RAPIDLY
CONSOLIDATED AND REACHED TROPICAL STORM STRENGTH IN THE CORAL SEA.
THE SYSTEM IS FORECAST TO TRACK GENERALLY WESTWARD THROUGH THE
MAJORITY OF THE FORECAST PERIOD, ALONG THE NORTHERN SIDE OF A DEEP
STR COMPLEX TO THE SOUTH. TC 06P IS EXPECTED TO MAKE LANDFALL ALONG
THE EAST COAST OF THE SOUTHERN CAPE YORK PENINSULA WITHIN THE NEXT
24 TO 30 HOURS, THEN TRACK ACROSS THE PENINSULA AND EMERGING INTO
THE GULF OF CARPENTARIA BY AROUND TAU 48. AT THE TAIL END OF THE
FORECAST PERIOD, THE RIDGE TO THE SOUTH IS EXPECTED TO WEAKEN
ENOUGH TO ALLOW FOR THE SYSTEM TO SLOW AS IT MAKES ITS SECOND
LANDFALL IN THE SOUTHWESTERN CORNER OF THE GULF OF CARPENTARIA,
THEN TURN SOUTHWEST INTO THE INTERIOR OF NORTHERN AUSTRALIA. UNDER
FAVORABLE CONDITIONS INCLUDING VERY WARM SSTS, LOW TO MODERATE VWS
VALUES AND GOOD RADIAL OUTFLOW ALOFT, THE SYSTEM IS FORECAST TO
INTENSIFY TO 55 KNOTS JUST PRIOR TO LANDFALL, FOLLOWED BY 20 KNOTS
OF WEAKENING AS IT CROSSES THE PENINSULA DUE TO LAND INTERACTIONS.
ONCE IT EMERGES OVER THE VERY WARM, SHALLOW WATERS OF THE GULF, THE
SYSTEM WILL ONCE AGAIN INTENSIFY, THIS TIME TO A PEAK OF 60 KNOTS
PRIOR TO THE SECOND LANDFALL, FOLLOWED ONCE MORE BY STEADY
WEAKENING OVER LAND. 

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN
GOOD AGREEMENT, TRACKING THE SYSTEM STEADILY WESTWARD INTO THE
SOUTHWESTERN PORTION OF THE GULF OF CARPENTARIA BY TAU 120. THE
MAJOR OUTLIERS ARE THE GFS AND GFS ENSEMBLE, WHICH KEEP THE SYSTEM
TRACKING QUICKLY TO THE WEST , WITH THE TRACK TO THE SOUTHWEST OF
DARWIN BY TAU 120, AND THE NAVGEM, WHICH TURNS THE TRACK TO THE
SOUTHEAST IMMEDIATELY AFTER MOVING OVER THE GULF. THE JTWC FORECAST
TRACK IS CONSISTENT WITH THE REMAINDER OF THE GUIDANCE, WHICH IS
TIGHTLY PACKED ABOUT THE CONSENSUS MEAN. CONFIDENCE IS HIGH THROUGH
TAU 72, DECREASING TO MEDIUM THEREAFTER IN LIGHT OF THE INCREASED
SPREAD. INTENSITY GUIDANCE IS IN GENERAL AGREEMENT ON THE INTENSITY
TRENDS WITH A 15-20 KNOT SPREAD BETWEEN OUTLIERS. THE HWRF IS THE
MOST AGGRESSIVE, WHILE THE COAMPS-TC IS THE LEAST AGGRESSIVE
THROUGH TAU 24. THE JTWC FORECAST TRACKS THE HWRF THOUGH THE FIRST
LANDFALL. THEREAFTER THE MODELS SHOW A LARGE SPREAD, WITH THE GFS
SEEING LITTLE IN THE WAY OF INTENSIFICATION AS IT RAPIDLY
TRANSLATES THE SYSTEM WESTWARD. MEANWHILE THE COAMPS-TC INTENSIFIES
THE SYSTEM TO A PEAK OF 135 KNOTS BY TAU 96, WHICH IS EQUALLY
UNLIKELY. THE JTWC FORECAST CLOSELY TRACKS THE CONSENSUS MEAN, WITH
LOW CONFIDENCE IN THE EXTENDED FORECAST DUE TO THE EXTREMELY LARGE
SPREAD IN POTENTIAL SOLUTIONS.  

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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