WDXS31 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (VERNON) WARNING 
NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.3S 87.2E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 968 NM EAST-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAGGED
CIRCULATION WITH CONVECTION BEING SHEARED TO THE SOUTHEAST. A
282211Z SSMIS 91GHZ IMAGE DEPICTS A SYSTEM WITH FRAGMENTED
CONVECTION ON THE SOUTHERN SIDE OF THE CIRCULATION. THE INITIAL
POSITION IS BASED ON AN EXTRAPOLATION FROM THE CENTER OF THE LOW
LEVEL BANDING IN THE PREVIOUSLY MENTIONED SSMIS IMAGE. THE INITIAL
INTENSITY OF 45 KTS IS HEDGED SLIGHTLY LOWER THAN AGENCY DVORAK
CURRENT INTENSITY ESTIMATES BASED ON AN OBSERVED WEAKENING TREND IN
THE DT AND ALSO SEEN IN THE RAW ADT. TC 14S IS CURRENTLY IN A
MARGINAL ENVIRONMENT CHARACTERIZED BY MODERATE VERTICAL WIND SHEAR
AND LOW OCEAN HEAT CONTENT DUE TO THE SYSTEM PASSING OVER ITS
PREVIOUS TRACK.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   FMEE: T3.5 - 55 KTS
   CIMSS SATCON: 51 KTS AT 281941Z
   CIMSS ADT: 49 KTS AT 010015Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: LOW OCEAN HEAT CONTENT DUE TO THE SYSTEM PASSING
OVER ITS PREVIOUS TRACK

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 14S WILL CONTINUE GENERALLY
SOUTH-SOUTHWESTWARD UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE TO
THE SOUTHEAST. THE SYSTEM IS EXPECTED TO CONTINUE THIS DIRECTION
FOR THE REMAINDER OF THE FORECAST PERIOD. OVER THE NEXT 24 HOURS,
AS TC 14S MOVES AWAY FROM THE POOL OF LOW OCEAN HEAT CONTENT, IT
MOVES INTO WARMER WATERS AND INCREASES SLIGHTLY IN INTENSITY. AROUND
TAU 36, THE SYSTEM WILL REACH 55 KTS AND REMAIN AROUND THAT
INTENSITY UNTIL TAU 72. BY THIS TIME, TC 14S WILL BEGIN SUBTROPICAL
TRANSITION AS IT BEGINS TO EXPERIENCE HIGHER WIND SHEAR AND COOLER
SEA SURFACE TEMPERATURES AS IT MOVES FARTHER SOUTH. IT IS EXPECTED
TO COMPLETE SUBTROPICAL TRANSITION BY TAU 96.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT IN REGARDS
TO TRACK FORECAST WITH ALL MODELS INDICATING A GENERALLY
SOUTH-SOUTHWESTWARD TRACK FOR THE REMAINDER OF THE FORECAST PERIOD,
BUT THERE IS A 230 NM CROSS-TRACK SPREAD AT TAU 96. THE JTWC
FORECAST TRACK IS PLACED SLIGHTLY WEST OF CONSENSUS, FAVORING THE
GFS AND ECMWF MODEL TRACKS. INTENSITY GUIDANCE IS IN GOOD AGREEMENT
WITH ALL MODELS INDICATING MODERATE INTENSIFICATION TO ABOUT 55-60
KTS PEAKING AROUND TAU 60, AND THEN FOLLOWED BY A GRADUAL WEAKENING
TREND AS THE SYSTEM MOVES SOUTH.

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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