WDXS31 PGTW 172100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (BHEKI) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.8S 69.9E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 744 NM EAST-NORTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 02S (BHEKI) WITH A DEFINED EYE, HOWEVER THE SYSTEM IS
BEGINNING TO FEEL SOME NORTHWESTERLY SHEAR AS SHOWN BY THE
DEFORMATION IN THE NORTHWESTERN QUADRANT OF THE EYEWALL.
ENVIRONMENTAL ANALYSIS INDICATES THAT THE ENVIRONMENT IS CURRENTLY
MARGINALLY FAVORABLE BUT IS EXPECTED TO CONTINUE WORSENING. THE
CURRENT ENVIRONMENT IS CHARACTERIZED BY STRONG POLEWARD OUTFLOW
ALOFT, LOW TO MODERATE (15-20 KTS) VERTICAL WIND SHEAR, AND
MARGINAL (25-26 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE IN ANIMATED EIR
IMAGERY. THE INITIAL INTENSITY OF 115 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE INTENSITY
ESTIMATES LISTED BELOW. ADDITIONALLY, A 171344Z RCM-2 SAR IMAGE
SHOWED A VMAX OF 122 KTS LOCALIZED TO A SMALL AREA IN THE
SOUTHWESTERN PORTION OF THE EYEWALL WITH 105-110 KTS ELSEWHERE
WITHIN THE EYEWALL.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: 02S IS CURRENTLY PLACED WITHIN A WEAK
STEERING ENVIRONMENT WITH RIDGING TO BOTH THE EAST AND WEST OF THE
SYSTEM.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   KNES: T6.0 - 115 KTS
   DEMS: T6.0 - 115 KTS
   FMEE: T6.0 - 115 KTS
   CIMSS ADT: 107 KTS AT 171800Z
   CIMSS AIDT: 102 KTS AT 171800Z
   CIMSS DPRINT: 110 KTS AT 171800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG 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: 02S IS FORECAST TO MEANDER SOUTHWESTWARD,
WITHIN THE WEAK STEERING ENVIRONMENT, THROUGH TAU 24. AFTER TAU 24,
RIDGING WILL BUILD TO THE SOUTH OF THE SYSTEM AND TAKE OVER AS THE
PRIMARY STEERING MECHANISM THROUGH THE REMAINDER OF THE FORECAST
PERIOD. REGARDING INTENSITY, 02S IS FORECAST TO ENTER A MORE
UNFAVORABLE ENVIRONMENT DUE TO COOLING SEA SURFACE TEMPERATURES,
INCREASING VERTICAL WIND SHEAR, AND DRY AIR ENTRAINMENT. AS A
RESULT, 02S IS EXPECTED TO RAPIDLY WEAKEN THROUGH TAU 36 TO AROUND
50 KTS. AFTER TAU 36, THE SYSTEM IS FORECAST TO WEAKEN MORE
GRADUALLY WITH WEAKENING BELOW TROPICAL STORM STRENGTH ANTICIPATED
NEAR TAU 96 JUST WEST OF LA REUNION ISLAND.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE STAYS IN MODERATE
AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH A 200 NM CROSS-TRACK
SPREAD AT TAU 48 WHICH OPENS TO 330 NM AT TAU 96. GFS IS THE
NORTHERNMOST MEMBER WHILE ECMWF IS THE SOUTHERNMOST MEMBER. THE
JTWC TRACK FORECAST IS PLACED CLOSE TO CONSENSUS THROUGHOUT THE
FORECAST WITH OVERALL MEDIUM CONFIDENCE. INTENSITY GUIDANCE IS ALSO
IN MODERATE AGREEMENT WITH HAFS-A REMAINING STRONGER THAN HWRF AND
GFS. ALL MODELS DO SUGGEST A WEAKENING TREND STARTING AT TAU 0
THOUGH. THE JTWC INTENSITY FORECAST IS PLACED WITHIN THE MIDDLE
GROUND OF GUIDANCE THROUGH TAU 36 AND CLOSER TO HWRF AND GFS
AFTERWARD WITH MEDIUM CONFIDENCE. 

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