WDXS31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 09S (NINE)       
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.2S 67.7E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 704 NM EAST OF ST DENIS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FLARING
DEEP CONVECTION, DISPLACED OVER THE EASTERN SEMICIRCLE DUE TO MODERATE 
TO HIGH VERTICAL WIND SHEAR, WITH A PARTIALLY-EXPOSED LOW-LEVEL 
CIRCULATION. A 012247Z SSMIS 37 GHZ MICROWAVE IMAGE DEPICTS WEAK 
BANDING OVER THE EASTERN SEMICIRCLE WITH A DEFINED NOTCH. 
ENVIRONMENTAL CONDITIONS HAVE DEGRADED WITH A DEEP UPPER-LEVEL TROUGH 
IMPINGING ON THE WESTERN PERIPHERY OF THE SYSTEM. THE INITIAL POSITION 
IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE SSMIS IMAGE. THE INITIAL 
INTENSITY OF 35 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE 
AGENCY DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WEAK SUBTROPICAL RIDGE (STR) POSITIONED
TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 31 KTS AT 012100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 09S IS FORECAST TO
ACCELERATE SOUTHEASTWARD AS THE STR STRENGTHENS TO THE EAST AND A
HIGH AMPLITUDE STEERING PATTERN SETS UP. THIS STEERING PATTERN WILL
DRIVE THE SYSTEM SOUTHEASTWARD THROUGH THE FORECAST PERIOD WITHIN
THE ENHANCED FLOW BETWEEN THE STR AND A DEEP UPPER-LEVEL TROUGH.
THE SYSTEM WILL CONTINUE TO INTERACT WITH THE DEEP UPPER-LEVEL
TROUGH AND COMMENCE SUBTROPICAL TRANSITION BY TAU 24 AS IT TRACKS
UNDER A SUBTROPICAL JET. VWS WILL INCREASE TO 35 TO 45 KNOTS WITH
DRY AIR ENVELOPING THE SYSTEM AFTER TAU 24. SOME INTENSIFICATION IS
LIKELY BUT IS ASSOCIATED WITH THE AFOREMENTIONED DEEP UPPER-LEVEL
TROUGH AS THE SYSTEM COMPLETES SUBTROPICAL TRANSITION. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT
LENDING HIGH OVERALL CONFIDENCE IN THE JTWC TRACK FORECAST. THERE
IS HIGH CONFIDENCE IN THE JTWC INTENSITY FORECAST, WITH GUIDANCE
INDICATING A PEAK INTENSITY IN THE 40 TO 60 KNOT RANGE IN THE TAU
36 TO TAU 48 TIMEFRAME. 

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