WDXS31 PGTW 262100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (TWO) WARNING NR 
001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.1S 82.6E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 697 NM EAST-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 13 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
CONSOLIDATING SYSTEM WITH THE ASSOCIATED CONVECTION BEING DISPLACED
TO THE SOUTHWEST OF AN ASSESSED LOW LEVEL CIRCULATION CENTER
(LLCC). THIS DISPLACEMENT IS CAUSED BY STRONG (30-35 KTS) UPPER
LEVEL WIND FLOW FROM THE NORTHEAST. A BULLSEYE 261633Z ASCAT-B PASS
SHOWS THE WELL DEFINED LLCC SURROUNDED PREDOMINATELY BY 30 KNOT
WIND BARBS WITH POCKETS OF 35 KNOT WINDS IN THE WESTERN AND EASTERN
SEMI-CIRCLES. TROPICAL CYCLONE 02S IS IN A MARGINALLY FAVORABLE
ENVIRONMENT FOR FURTHER DEVELOPMENT CHARACTERIZED BY STRONG (30-35
KTS) POLEWARD OUTFLOW ALOFT AND WARM (27-28 C) SEAS SURFACE
TEMPERATURES (SSTS), OFFSET BY STRONG (35-40 KTS) VERTICAL WIND
SHEAR (VWS). THE INITIAL POSITION AND THE INITIAL INTENSITY ARE
PLACED WITH HIGH CONFIDENCE BASED OFF THE AFOREMENTIONED ASCAT-B
PASS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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

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

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 35-40 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR DOWNSTREAM OF FORECAST TRACK

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: TC 02S WILL TRANSIT WESTWARD OVER THE NEXT 24
HOURS AS IT RIDES ALONG THE NORTHWEST SECTOR OF THE STR. THE SYSTEM
WILL SLOWLY BEGIN TO WEAKEN IN INTENSITY FROM 40 KNOTS TO 35 KNOTS
BY TAU 24 AS THE ENVIRONMENT WILL BECOME LESS FAVORABLE DUE TO
INCREASED VWS. AFTER TAU 24, TC 02S WILL MAKE A SLIGHT TURN AND
HEAD ON A MORE WEST-SOUTHWESTWARD TRACK AS IT WILL ATTEMPT TO ROUND
THE STR AXIS. HOWEVER, THE SYSTEM WILL BEGIN TO DISSIPATE AT THIS
TIME DUE TO THE WORSENING ENVIRONMENT CHARACTERIZED BY UNFAVORABLE
VWS AND THE INTRODUCTION OF DRY AIR WRAPPING INTO THE LLCC FROM THE
WEST.

MODEL DISCUSSION: THE TRACK MODEL CONSENSUS MEMBERS ARE IN TIGHT
AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH A 23 NM SPREAD AT TAU
12, GRADUALLY INCREASING TO ITS LARGEST SPREAD OF 54 NM BY TAU 36.
THIS TIGHT AGREEMENT IN CONSENSUS LENDS HIGH CONFIDENCE IN THE
FORECAST TRACK. INTENSITY MODEL GUIDANCE HAS A SPREAD OF ROUGHLY 10
KNOTS BETWEEN GFS AND COAMPS AT TAU 12. HOWEVER, THE OVERALL
CONSENSUS SHOWS A WEAKENING TREND AFTER TAU 24. THE JTWC FORECAST
INTENSITY IS SET WITH MEDIUM CONFIDENCE DUE TO THE CONSISTENT
SPREAD OF 10 KNOTS AMONG THE CONSENSUS MEMBERS.

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