WDXS33 PGTW 052100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (TALIAH)     
WARNING NR 010//   
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.8S 106.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 553 NM EAST-SOUTHEAST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 31 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 14S HAS CONTINUED TO STRUGGLE UNDER MARGINAL
ENVIRONMENTAL CONDITIONS CHARACTERIZED BY HIGH VERTICAL WIND SHEAR
(VWS) AND DRY AIR ENTRAINMENT. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A LARGE REGION OF DEEP CONVECTION 
PERSISTING OVER THE WESTERN SEMICIRCLE DUE TO THE ROBUST EASTERLY
DIFFLUENT FLOW. A 051840Z GMI 37GHZ MICROWAVE IMAGE REVEALS AN
ELONGATED LOW-LEVEL CIRCULATION CENTER, WITH CONVECTIVE BANDING
OVER THE SOUTHERN QUADRANT WRAPPING INTO THE NORTHERN QUADRANT. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE GMI
IMAGE. THE 051446Z ASCAT UHR WINDSPEED AND NRCS IMAGERY ALSO SHOWED
A DEFINED CENTER SUPPORTING THE INITIAL POSITION DETERMINATION. THE
INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON AN AVERAGE OF THE SUBJECTIVE DVORAK ESTIMATES. CIMSS
OBJECTIVE INTENSITY ESTIMATES ARE GENERALLY LOWER AND RANGE FROM
40-49 KNOTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
ENTRENCHED TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   CIMSS SATCON: 54 KTS AT 051614Z
   CIMSS ADT: 53 KTS AT 051730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 25-30 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE WESTWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT OVER THE EASTERN SEMICIRCLE.

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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) 14S IS FORECAST TO TRACK
GENERALLY WESTWARD THROUGH THE FORECAST PERIOD ALONG THE NORTHERN
PERIPHERY OF THE SUBTROPICAL RIDGE. THE SYSTEM WILL CONTINUE TO
WEAKEN UNDER HIGH VERTICAL WIND SHEAR (VWS) AND DRY AIR ENTRAINMENT
THROUGH TAU 24, MAINTAINING 50 KNOTS OR SO FROM TAU 24 TO TAU 48.
AFTER TAU 48, TC 14S IS EXPECTED TO GRADUALLY RE-MOISTEN AND
CONSOLIDATE WITH A MARKED RE-INTENSIFICATION TREND TO 70 KNOTS BY
TAU 120. VWS IS FORECAST TO DECREASE STEADILY AFTER TAU 36, WITH
SST VALUES REMAINING STABLE AT 27-28C.   

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 72, WITH INCREASING UNCERTAINTY AFTER TAU 72. BOTH THE
EPS AND GEFS ENSEMBLES ALSO INDICATE HIGH UNCERTAINTY AFTER TAU 96,
WITH A LARGE SPREAD IN SOLUTIONS. RELIABLE INTENSITY GUIDANCE IS IN
FAIR AGREEMENT AND GENERALLY SUPPORTS THE JTWC INTENSITY FORECAST
WITH MEDIUM CONFIDENCE.      

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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