WDXS31 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (BHEKI) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.6S 59.7E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 139 NM EAST-NORTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 02S (BHEKI) WITH AN EXPOSED LOW-LEVEL CIRCULATION CENTER
(LLCC) AND SCARCE BURSTS OF CONVECTION WITHIN THE SOUTHERN
PERIPHERY. ENVIRONMENTAL ANALYSIS INDICATES THAT 02S IS IN AN
UNFAVORABLE ENVIRONMENT CHARACTERIZED BY WEAK POLEWARD OUTFLOW,
HIGH (25-30 KTS) VERTICAL WIND SHEAR, EXTENSIVE DRY AIR, AND COOL
(25-26 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION AND
INTENSITY ARE PLACED WITH HIGH CONFIDENCE BASED ON A 201707Z
ASCAT-B IMAGE SHOWING A LARGE SWATH OF 30 KNOT WINDS IN THE
SOUTHERN PERIPHERY, HEDGED 5 KTS HIGHER BASED ON THE SLIGHTLY LOW
BIAS OF ASCAT. AGENCY DVORAK ESTIMATES SUGGEST A LOWER INTENSITY
DUE TO THE LACK OF CONVECTION OVER THE SYSTEM.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   FIMP: T2.0 - 30 KTS
   CIMSS ADT: 25 KTS AT 201800Z
   CIMSS AIDT: 37 KTS AT 201800Z
   CIMSS DPRINT: 28 KTS AT 201800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 25-30 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: EXTENSIVE DRY AIR ENTRAINMENT

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: 02S IS FORECAST TO CONTINUE TRACKING
WEST-SOUTHWESTWARD, ALONG THE WESTERN PERIPHERY OF THE STR TO THE
EAST THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD. 02S IS
FORECAST TO MAINTAIN A 35 KNOT INTENSITY, OVERCOMING THE HIGH SHEAR
AND LOW SEA SURFACE TEMPERATURES, DUE TO A MOISTENING OF THE VORTEX
OVER THE NEXT 36 HOURS AS DEPICTED BY MULTIPLE MODELS. AFTER TAU
36, THE ENVIRONMENT WILL WORSEN AS THE MOISTURE DISAPPEARS AND DRY
AIR FURTHER DEGRADES THE SYSTEM. AS A RESULT, 02S IS FORECAST TO
DISSIPATE SOUTHWEST OF LA REUNION ISLAND AROUND TAU 48. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY GOOD
AGREEMENT REGARDING THE TRACK OF 02S WITH A 72 NM CROSS-TRACK
SPREAD AT TAU 48. INTENSITY GUIDANCE IS IN WORSE AGREEMENT WITH
MULTIPLE MODELS ACTUALLY INTENSIFYING THE SYSTEM OVER THE NEXT
24-36 HOURS. IN PARTICULAR, COAMPS-TC SUGGESTS A 45 KNOT SYSTEM AT
TAU 24. HAFS-A AND HWRF BOTH SUGGEST A 40 KNOT SYSTEM AT TAU 36.
THE JTWC INTENSITY FORECAST IS PLACED BELOW CONSENSUS DUE TO THE
UNFAVORABLE ENVIRONMENT EXPECTED TO HINDER THE CHANCES OF
REINTENSIFICATION. 

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