WDXS33 PGTW 142100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (TALIAH) WARNING NR 
028//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.5S 83.8E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 1170 NM EAST-SOUTHEAST OF MATHURIN,
RODRIGUES ISLAND, MAURITIUS OF KEY WEST
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED
SYSTEM IN THE SOUTH INDIAN OCEAN THAT CONTINUES TO STRUGGLE AGAINST
STRONG VERTICAL WIND SHEAR (VWS), COOL DRY AIR INTRUSION IN THE LOW
TO MID LEVELS, AND COOLING SEA SURFACE TEMPERATURES (SST). THE LOW
LEVEL CIRCULATION (LLC) REMAINS PARTIALLY EXPOSED DUE TO THE HIGH
NORTHERLY VWS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE PARTLY EXPOSED LLC THAT LINED UP PERFECTLY WITH A
BULLSEYE IN THE 141642Z ASCAT DIRECT PASS. THE INITIAL INTENSITY OF
40KTS, HELD HIGHER THAN AGENCY AND AUTOMATED ESTIMATES, IS ALSO PLACED 
WITH HIGH CONFIDENCE BASED ON THE ASCAT PASS THAT SHOWED A LARGE PATCH 
OF 40-KT WIND BARBS WRAPPING IN FROM THE SOUTHWEST QUADRANT. ANALYSIS 
INDICATES A MARGINAL ENVIRONMENT WITH HIGH VWS, COOL SST, AND DRY AIR 
INTRUSION OFFSET BY STRONG POLEWARD OUTFLOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 33 KTS AT 141800Z
   CIMSS ADT: 36 KTS AT 141800Z
   CIMSS ADT: 31 KTS AT 141500Z
   CIMSS DPNT: 29 KTS AT 141500Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 25-30 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG POLEWARD

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: TC TALIAH WILL CONTINUE TO TRACK SOUTHWESTWARD
UNDER THE STEERING STR TO THE EAST. AFTER TAU 72, A SECONDARY STR
BUILDING IN FROM THE WEST WILL COMPETE FOR STEERING, RESULTING IN A
SLOWED-DOWN POLEWARD STORM MOTION. THE MARGINAL ENVIRONMENT WILL
GRADUALLY BECOME UNFAVORABLE AS VWS AND DRY AIR INTRUSION CONTINUE
TO INCREASE AND SST BECOME COLDER RESULTING IN A GRADUAL WEAKENING
LEADING TO DISSIPATION BY TAU 96, POSSIBLY SOONER.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY GOOD AGREEMENT WITH
A GRADUAL AND EVEN SPREAD TO A MERE 103NM BY TAU 72, BUT SPREADS OUT
MORE TO OVER 300NM BY TAU 120. DESPITE THE TIGHT GROUPING OF THE
MODELS UP TO TAU 72, THERE IS ONLY MEDIUM CONFIDENCE IN THE JTWC
TRACK FORECAST UP TO TAU 72 DUE TO THE POSSIBILITY OF EARLY
DISSIPATION. SAME GOES TO THE INTENSITY FORECAST. 

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