WDXS31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (BHEKI) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.0S 76.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 313 NM SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND IMAGERY FROM
A 150036Z SSMIS PASS DEPICT TIGHTLY CURVED DEEP CONVECTIVE BANDING
PERSISTING OVER A COMPACT LOW-LEVEL CIRCULATION (LLC). THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON RECENT SATELLITE
POSITION FIXES FROM PGTW, KNES, AND FMEE. THE INITIAL INTENSITY OF
60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A CONSENSUS OF
AVAILABLE SUBJECTIVE DVORAK AND AUTOMATED INTENSITY ESTIMATES
DISTRIBUTED WITHIN A RANGE FROM 45 KNOTS (DEMS DVORAK) TO 68 KNOTS
(CIMSS D-PRINT). TROPICAL CYCLONE (TC) 02S HAS INTENSIFIED OVER THE
PAST 12 HOURS, SUPPORTED BY PASSAGE OVER VERY WARM WATER AND A
FAVORABLE UPPER-LEVEL OUTFLOW PATTERN.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T3.0 - 45 KTS
   FMEE: T3.5 - 55 KTS
   CIMSS ADT: 59 KTS AT 142100Z
   CIMSS AIDT: 51 KTS AT 142300Z
   CIMSS D-PRINT: 68 KTS AT 142330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 02S IS CURRENTLY TRACKING SOUTH-SOUTHWESTWARD
ALONG THE NORTHWESTERN PERIPHERY OF THE STEERING STR, TOWARD A
SHORTWAVE TROUGH ANALYZED TO THE SOUTHWEST. AS THIS SHORTWAVE
TROUGH TRANSLATES EASTWARD, CONTINUOUS RIDGING IS EXPECTED TO BUILD
TO THE SOUTH OF TC 02S AND GRADUALLY STEER THE SYSTEM TOWARD A
WESTWARD TRAJECTORY. PASSAGE OVER WARM WATER AND FAVORABLE OUTFLOW
WILL SUPPORT INTENSIFICATION IN THE NEAR-TERM, BUT PERSISTENT
MODERATE EASTERLY VERTICAL WIND SHEAR (VWS) IS EXPECTED TO LIMIT
THE INTENSIFICATION RATE. VWS IS EXPECTED TO DROP TOWARD MORE
FAVORABLE VALUES AFTER TAU 24, ALLOWING FOR MORE PRONOUNCED
INTENSIFICATION THROUGH TAU 72. THEREAFTER, INCREASING WESTERLY VWS
AND PASSAGE OVER COOLER WATER ARE EXPECTED TO ARREST THE
INTENSIFICATION TREND AND BEGIN WEAKENING THE SYSTEM. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE, WITH THE EXCEPTION OF
THE NAVGEM POLEWARD OUTLIER, IS IN GOOD AGREEMENT REGARDING THE
OVERALL FORECAST SCENARIO AND ASSOCIATED TRACK THROUGH TAU 72.
THEREAFTER, SPREAD IN DIRECTION AND SPEED INCREASES DUE TO VARYING
DEPICTIONS OF THE STEERING RIDGE EVOLUTION AND STORM STRUCTURE. THE
CURRENT FORECAST LIES CLOSE TO THE MULTI-MODEL CONSENSUS AND
PREVIOUS JTWC FORECAST WITH HIGH CONFIDENCE THROUGH TAU 72 AND
MEDIUM CONFIDENCE THEREAFTER. NUMERICAL INTENSITY FORECAST GUIDANCE
SUPPORTS SLOW INTENSIFICATION IN THE NEAR-TERM UNDER MODERATE
VERTICAL WIND SHEAR FOLLOWED BY STEADY INTENSIFICATION
AFTER TAU 24 AND WEAKENING LATE IN THE FORECAST PERIOD. HAFS AND
HWRF INDICATE POTENTIAL FOR INTENSIFICATION ABOVE THE CURRENT
FORECAST BETWEEN TAU 12 AND TAU 72, WHICH IS POSSIBLE IF SHEAR DROPS 
SIGNIFICANTLY GIVEN THAT OTHER ENVIRONMENTAL FACTORS ARE FAVORABLE. 
CONFIDENCE IN THE INTENSITY FORECAST IS MEDIUM THROUGH TAU 120.

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