WDXS32 PGTW 180300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 10S (TEN) WARNING NR 
001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.3S 119.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 66 NM NORTH-NORTHEAST OF PORT HEDLAND,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDS
OF DEEP CONVECTION RAPIDLY CONSOLIDATING AND WRAPPING INTO AN
OBSCURED LOW-LEVEL CIRCULATION (LLCC). THE INITIAL POSITION IS PLACED 
WITH HIGH CONFIDENCE BASED ON THE ANIMATED MSI AND RADAR IMAGERY. TC 
10S IS DEVELOPING AS A RESULT OF TWO CIRCULATIONS MERGING TOGETHER, 
RESULTING IN A BROAD SURFACE PRESSURE FIELD. THE INITIAL INTENSITY OF 
35 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON NEARBY AUTOMATED 
OBSERVATIONS FROM THE BEDOUT ISLAND REPORTING 30-33 KNOT WIND SPEEDS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA AND SURFACE OBSERVATIONS. 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE BUILDING TO THE
SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE 10S IS FORECAST TO PROCEED ON
A WESTWARD TRACK OVER THE NEXT 12 HOURS, AFTER WHICH IT WILL BEGIN
TO ROUND THE AXIS OF THE STR TO THE SOUTHEAST, LEADING TO A TRACK
ALONG THE NORTHWESTERN AUSTRALIAN COAST. PAST TAU 48 THE SYSTEM
WILL SLOWLY START TURNING LEFT, WHILE STILL HEADING IN A
SOUTHWESTWARD DIRECTION THROUGHOUT THE END OF THE FORECAST PERIOD.
ENVIRONMENTAL CONDITIONS WILL REMAIN HIGHLY FAVORABLE FOR
DEVELOPMENT OVER THE NEXT 60 HOURS, WITH HIGH SEA SURFACE
TEMPERATURES (27-30 DEGREES CELSIUS), LOW AND VARIABLE VERTICAL
WIND SHEAR, HIGH ATMOSPHERIC COLUMN MOISTURE CONTENT, AS WELL AS
SUPPORTIVE DIVERGENCE ALOFT. SUCH SETTING IS REFLECTED BY A
SIGNIFICANT POTENTIAL FOR RAPID INTENSIFICATION (RI) WITHIN THE
NEXT 48 HOURS, AS ALSO INDICATED BY NUMEROUS RI INTENSITY AIDS. 10S
IS ASSESSED TO REACH PEAK INTENSITY 90 KTS, WITH A POTENTIAL OF
FURTHER INTENSIFICATION BETWEEN TAUS 48 AND 60. AFTER TAU 60, TC
10S WILL START DEPARTING FROM THE AREA OF FAVORABLE CONDITIONS DUE TO 
RAPIDLY DECREASING SEA SURFACE TEMPERATURE (DOWN TO
23-24 DEGREES CELSIUS), INCREASING VERTICAL WIND SHEAR, AS WELL AS
PROGRESSING DRY AIR ENTRAINMENT. AS THE SYSTEM GETS CLOSER TO TAU
96, IT WILL QUICKLY BEGIN DETERIORATING.  

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT IN
TERMS OF TRACK, WITH JUST 90 NM CROSS-TRACK SPREAD BY TAU 72 AND
ALL GUIDANCE CONSISTENT WITH A SOUTHWESTWARD TRACK, ALONG THE
NORTHWESTERN PERIPHERY OF A BUILDING STR TO THE SOUTHEAST. JTWC
TRACK IS LAID IN A CLOSE PROXIMITY AND SLIGHTLY TO THE NORTH OF THE
MULTI-MODEL CONSENSUS. INTENSITY GUIDANCE ALSO REMAINS FAIRLY
CONSISTENT WITH NEARLY ALL GUIDANCE INDICATING RAPID
INTENSIFICATION OVER THE NEXT 48 HOURS, WITH JUST DETERMINISTIC GFS
BEING THE OUTLIER PROJECTING A SHALLOWER GRADE OF INTENSIFICATION. 
AFTER TAU 60, ALL GUIDANCE INDICATES A STEADY WEAKENING
TREND LEADING A EVENTUAL DISSIPATION AT THE END OR JUST BEYOND THE
END OF THE CURRENT FORECAST PERIOD.

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