WDXS31 PGTW 292100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 10S (HAYLEY) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.1S 120.3E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 153 NM NORTHWEST OF BROOME, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 10S (HAYLEY) AS AN INTENSIFYING SYSTEM WITH AN
OBSERVABLE EYE-FEATURE, SURROUNDED BY A RELATIVELY UNIFORM COMPACT
CONVECTIVE STRUCTURE. A SUPPORTIVE CONVECTIVE BAND HAS CONTINUED
TO EXTEND THROUGHOUT THE SOUTHERN SEMICIRCLE, WITH AN ADDITIONAL
BAND EXTENDING EASTWARD OVER THE DAMPIER PENINSULA. MODERATE
POLEWARD OUTFLOW HAS BEEN EVIDENT ON ANIMATED WATER VAPOR IMAGERY,
WITH A SOUTHEASTWARD CHANNEL ALOFT. THE ENVIRONMENT HAS REMAINED
CONDUCIVE FOR INTENSIFICATION, WITH WARM SEA SURFACE TEMPERATURES
(29-30 C), LOW VERTICAL WIND SHEAR (5-10 KTS), AND THE
AFOREMENTIONED MODERATE UPPER-LEVEL OUTFLOW CHANNEL. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 291713Z AMSR-2
MICROWAVE IMAGE. THE INITIAL INTENSITY OF 90 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON A COMBINATION OF SUBJECTIVE DVORAK FIX
ESTIMATES AND CIMSS AUTOMATED INTENSITY ESTIMATES.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE LOCATED DIRECTLY
TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   DEMS: T4.5 - 77 KTS
   APRF: T5.5 - 102 KTS
   CIMSS SATCON: 78 KTS AT 291735Z
   CIMSS ADT: 79 KTS AT 291730Z
   CIMSS AIDT: 79 KTS AT 291730Z
   CIMSS D-MINT: 64 KTS AT 291735Z
   CIMSS D-PRINT: 86 KTS AT 291830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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 10S IS EXPECTED TO TRACK EAST-SOUTHEASTWARD
THROUGHOUT THE FORECAST PERIOD, ALONG THE SOUTHERN EXTENT OF THE
NEAR-EQUATORIAL RIDGE LOCATED DIRECTLY TO THE NORTH AND NORTHEAST.
TC HAYLEY IS FORECASTED TO CONTINUE SLOWLY INTENSIFYING OVER THE
NEXT 12 HOURS WHILE SEA SURFACE TEMPERATURES REMAIN WARM, VERTICAL
WIND SHEAR REMAINS LOW (LESS THAN 10 KTS), AND UPPER-LEVEL OUTFLOW
IS PREVALENT. AFTER TAU 12, VERTICAL WIND SHEAR IS FORECASTED TO
STEADILY INCREASE, HALTING CONTINUED INTENSIFICATION. AS THE SYSTEM
APPROACHES THE DAMPIER PENINSULA (BETWEEN TAU 20-24), MID-LEVEL
VERTICAL WIND SHEAR ABOVE 15 KTS WILL INJECT DRY AIR INTO THE
SYSTEM, INITIATING A WEAKENING TREND INTO TAU 24. AS THE SYSTEM
MAKES LANDFALL NEAR TAU 24 (OVER THE DAMPIER PENINSULA) AND AGAIN
NEAR TAU 30 (NEAR LACHLAN ISLAND), INCREASED VERTICAL WIND SHEAR
(ABOVE 20 KTS) AND LAND INTERACTION WILL CAUSE DISSIPATION BY THE
END OF THE FORECAST PERIOD. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT WITH REGARDS TO THE FORECAST TRACK SCENARIO. THE JTWC
FORECAST TRACK IS POSITIONED JUST SOUTH OF THE JTWC CONSENSUS,
NEARER TO THE ECMWF ENSEMBLE, ECMWF DETERMINISTIC, AND FGN
SOLUTIONS, ILLUSTRATING A CROSS-TRACK SPREAD OF 151 NM BY THE END
OF THE FORECAST PERIOD. A FEW OF THE SOLUTIONS CHARACTERIZE A
NORTHWARD TRACK NEAR TAU 48 AND AFTER, TO INCLUDE NAVGEM AND THE
ECMWF DETERMINISTIC NUMERICAL MODEL GUIDANCE. THEREFORE, THE JTWC
FORECAST TRACK IS LAID JUST SOUTH OF THE JTWC CONSENSUS TRACK,
LENDING MEDIUM CONFIDENCE TO THE FORECAST. INTENSITY GUIDANCE
CONTINUES TO AGREE ON CONTINUED INTENSIFICATION OVER THE NEXT 12
HOURS, WITH A SHARP DECLINE IN INTENSITY THEREAFTER AS THE SYSTEM
APPROACHES AUSTRALIAS NORTHWEST COASTLINE. RAPID INTENSIFICATION
(RI) AIDS HAVE CONTINUED TO INITIATE INTO TAU 12, HOWEVER,
INCREASING VERTICAL WIND SHEAR NEAR THE DAMPIER PENINSULA WILL LIMIT
INTENSIFICATION INTO TAU 24. THE JTWC INTENSITY FORECAST HAS BEEN
PLACED WITH MEDIUM CONFIDENCE, PEAKING AT 95 KTS, BASED ON
TRIGGERED RI AIDS AND EXPECTED MODERATE VERTICAL WIND SHEAR AS THE
SYSTEM NEARS LANDFALL.  

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