WDXS31 PGTW 290300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 10S (HAYLEY) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.7S 119.4E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 251 NM NORTHWEST OF BROOME, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 10S (HAYLEY) WITH A HIGHLY COMPACT LOW-LEVEL CIRCULATION
CENTER (LLCC) OBSCURED BY A CORE OF DEEP CONVECTION. CONVECTION HAS
BECOME MORE VIGOROUS OVER THE PAST 6 HOURS AND CONVECTIVE BANDING
HAS IMPROVED WITHIN THE SOUTHWESTERN QUADRANT. A 282132Z WSFM 37
GHZ MICROWAVE IMAGE REVEALED THAT THE SYSTEM HAS ATTAINED A
WELL-DEFINED MICROWAVE EYE, INDICATIVE OF AN INTENSIFYING SYSTEM. A
290032Z METOP-B ASCAT PASS SHOWED WINDS OF 45-50 KTS NEAR THE
CENTER. ADJUSTING FOR THE LOW BIAS OF ASCAT AT THESE WIND SPEEDS,
THE INITIAL INTENSITY OF 55 KTS IS PLACED WITH HIGH CONFIDENCE. THE
AGENCY DVORAK ESTIMATES ARE ANALYZED TO BE SLIGHTLY UNDERESTIMATING
THE CURRENT INTENSITY DUE TO THE HIGHLY COMPACT NATURE OF THE
SYSTEM. THE INITIAL POSITION IS ALSO PLACED WITH HIGH CONFIDENCE
BASED ON THE ASCAT. ENVIRONMENTAL ANALYSIS INDICATES THAT 10S
REMAINS WITHIN A FAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE
POLEWARD OUTFLOW, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND VERY WARM
(29-30 C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: 290032Z METOP-B ASCAT SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A
NEAR-EQUATORIAL RIDGE (NER) CENTERED OVER THE BANDA SEA

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   DEMS: T3.0 - 45 KTS
   APRF: T3.0 - 45 KTS
   CIMSS SATCON: 43 KTS AT 290020Z
   CIMSS ADT: 53 KTS AT 290020Z
   CIMSS AIDT: 41 KTS AT 290020Z
   CIMSS D-PRINT: 43 KTS AT 290020Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 10S IS FORECAST TO TRACK SOUTHEASTWARD,
ALONG THE SOUTHWESTERN PERIPHERY OF THE NER CENTERED OVER THE BANDA
SEA THROUGH TAU 24. NEAR TAU 24, 10S IS FORECAST TO TURN EASTWARD
AS IT ROUNDS THE SOUTHERN EXTENT OF THE NER. AN INITIAL LANDFALL
ALONG THE TIP OF THE DAMPIER PENINSULA IS FORECAST TO OCCUR JUST
AFTER TAU 36 WITH A FINAL LANDFALL ABOUT 6 HOURS LATER. AFTER THE
FINAL LANDFALL, 10S IS EXPECTED TO CONTINUE TRACKING EASTWARD
THROUGH THE REMAINDER OF THE FORECAST PERIOD. REGARDING INTENSITY,
10S IS FORECAST TO CONTINUE INTENSIFYING OVER THE NEXT 24 HOURS AS
THE SYSTEM TAPS INTO AN ENHANCED POLEWARD OUTFLOW CHANNEL DUE TO AN
UPPER-LEVEL TROUGH TO THE SOUTH. A PEAK INTENSITY IS FORECAST TO BE
AROUND 75 KTS NEAR TAU 24. AFTER TAU 24, NORTHWESTERLY SHEAR IS
EXPECTED TO QUICKLY INCREASE TO AROUND 20 KTS, CAUSING 10S TO
WEAKEN AS IT APPROACHES THE KIMBERLEY COAST. AFTER THE SYSTEM MAKES
A FINAL LANDFALL, TERRAIN INTERACTION WILL ERODE THE VORTEX AND
CAUSE IT TO WEAKEN BELOW 35 KTS NO LATER THAN TAU 72.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT WITH THE EXCEPTION OF NAVGEM, WHICH CONTINUES TO TRACK
THE VORTEX MUCH FURTHER NORTH THAN THE REMAINDER OF GUIDANCE.
DISCOUNTING NAVGEM, THERE IS A 75 NM CROSS-TRACK SPREAD AT TAU 48.
AFTER TAU 48, MODELS SLIGHTLY DIVERGE, PARTICULARLY IN THE
ALONG-TRACK DIRECTION. THE GOOGLE DEEPMIND AND ECMWF MODELS ARE THE
FASTEST WHILE THE GFS ENSEMBLE MEAN IS CONSIDERABLY SLOWER. AT TAU
72, ALONG-TRACK SPREAD INCREASES TO AROUND 190 NM, CAUSING THERE TO
BE SOME UNCERTAINTY REGARDING TRACK SPEEDS NEAR THE END OF THE
FORECAST PERIOD. THE JTWC TRACK FORECAST IS PLACED SLIGHTLY TO THE
SOUTH OF THE CONSENSUS, TO OFFSET NAVGEM, WITH MEDIUM CONFIDENCE.
INTENSITY GUIDANCE GENERALLY AGREES ON INTENSIFICATION THROUGH TAU
24 WITH WEAKENING AFTERWARD. HOWEVER, MANY RAPID INTENSIFICATION
(RI) AIDS ARE TRIGGERED THIS MODEL RUN, CAUSING THERE TO BE SOME
INHERENT UNCERTAINTY CONCERNING THE PEAK INTENSITY. WITHIN THE MAIN
GROUPING, PEAK INTENSITIES RANGE FROM 65 KTS TO 95 KTS (RI MODELS)
AT TAU 24. THE JTWC INTENSITY FORECAST FALLS IN THE MIDDLE, CALLING
FOR A PEAK OF 75 KTS. AFTERWARD, ALL MODELS AGREE ON WEAKENING, AND
THE JTWC INTENSITY FORECAST FOLLOWS THE CONSENSUS THROUGH THE
REMAINDER OF THE FORECAST PERIOD.

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