WDXS31 PGTW 280900
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: 13.1S 119.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 328 NM NORTH-NORTHWEST OF BROOME,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TC 10S HAS STEADILY CONSOLIDATED INTO A TROPICAL CYCLONE OVER THE
PAST SIX HOURS UNDER THE INFLUENCE OF SUPPORTIVE ENVIRONMENTAL
CONDITIONS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS
WELL DEFINED, THOUGH RELATIVELY SHALLOW, CONVECTIVE BANDING
WRAPPING TOWARD A LOW-LEVEL CIRCULATION CENTER EVIDENT IN A 280539Z
AMSR2 PASS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE AMSR2 DATA AND EXPOSED CENTER EVIDENT IN MSI. THE
INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON A CONSENSUS OF AVAILABLE SUBJECTIVE DVORAK AND AUTOMATED
INTENSITY ESTIMATES AND AN ASSESSMENT OF STRUCTURE EVIDENT IN MSI
AND OTHER RECENT SATELLITE IMAGERY.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP LAYER RIDGING TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   APRF: T2.0 - 30 KTS
   CIMSS D-PRINT: 33 KTS AT 280600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 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: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TC 10S IS EXPECTED TO TRACK GENERALLY POLEWARD
OVER THE NEXT 24 HOURS AND THEN TURN GRADUALLY EASTWARD AS RIDGING
TO THE EAST REORIENTS AND A BUILDING NEAR-EQUATORIAL RIDGE TO THE
NORTH BECOMES THE DOMINANT STEERING MECHANISM. FAVORABLE
ENVIRONMENTAL CONDITIONS INCLUDING LOW VERTICAL WIND SHEAR, A VERY
WARM SEA SURFACE, AND OUTFLOW ENHANCED BY PASSAGE OF AN UPPER-LEVEL
TROUGH TO THE SOUTH WILL SUPPORT STEADY TO POTENTIALLY RAPID
INTENSIFICATION FOR THE NEXT 36 HOURS. THEREAFTER, STRENGTHENING
UPPER-LEVEL WESTERLY WINDS ON THE EDGE OF A JET TO THE SOUTH WILL
INTRODUCE INCREASING AND PERSISTENT VERTICAL WIND SHEAR. THE
INCREASING SHEAR AND CONSEQUENT ENTRAINMENT OF DRIER AIR SHOULD
KICK OFF A WEAKENING TREND BEFORE THE SYSTEM MAKES AN ANTICIPATED
LANDFALL ALONG THE DAMPIER PENINSULA BETWEEN TAUS 48 AND 72.
CONTINUED UNFAVORABLE UPPER-LEVEL CONDITIONS AND PASSAGE OVER
LANDFALL WILL LEAD TO DISSIPATION BY TAU 96.

MODEL DISCUSSION: NUMERICAL MODEL TRACK FORECAST GUIDANCE IS IN
GOOD AGREEMENT REGARDING THE OVERALL FORECAST SCENARIO OF AN
INITIALLY POLEWARD TRACK FOLLOWED BY AN EASTWARD TURN. THE ECMWF
DETERMINISTIC, ECMWF ENSEMBLE, GFS AND GEFS SOLUTIONS BRACKET THE
CURRENT JTWC FORECAST WHILE THE NAVGEM SOLUTION DEPICTS A SHARPER
EASTWARD TURN AND LIES WELL TO THE NORTH OF THE PRIMARY MODEL
GROUPING. DEVIATIONS AMONG THE SOLUTIONS REFLECT DIFFERING
PREDICTIONS OF THE EVOLUTION OF THE NEAR-EQUATORIAL STEERING RIDGE
TO THE NORTHEAST AND HAVE BEEN PRESENT FOR THE PAST SEVERAL MODEL
RUNS, LENDING SOME UNCERTAINTY TO THE CURRENT FORECAST AND THE
EVENTUAL LANDFALL POINT. INTENSITY FORECAST GUIDANCE IS TIGHTLY
PACKED DURING THE LATER WEAKENING STAGE BUT DEPICTS A RANGE OF PEAK
INTENSITIES BETWEEN 50 AND 75 KNOTS WITHIN 24 TO 36 HOURS. THE
CURRENT INTENSITY FORECAST LIES NEAR THE MULTI-MODEL CONSENSUS WITH
MEDIUM CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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