WDXS33 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (TALIAH)       
WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.9S 109.4E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 760 NM EAST-SOUTHEAST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 31 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS DEPICTED IN ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY,
TROPICAL CYCLONE (TC) 14S HAS WEAKENED OVER THE PAST 12 HOURS, WITH
INCREASINGLY ASYMMETRIC DEEP CONVECTION SHEARED OVER THE WESTERN
SEMICIRCLE. THE 041803Z AMSR2 89GHZ COLOR COMPOSITE AND 37GHZ COLOR
MICROWAVE IMAGERY SHOWS AN EXPOSED, WELL-DEFINED LOW-LEVEL
CIRCULATION CENTER, WITH EXPOSED SHALLOW BANDING, AND LIMITED DEEP
CONVECTIVE BANDING OVER THE WESTERN QUADRANT. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE AMSR2 IMAGERY. THE
INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE AGENCY DVORAK ESTIMATES. CIMSS OBJECTIVE INTENSITY
ESTIMATES ARE ASSESSED AS TOO LOW, IN GENERAL.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 62 KTS AT 041735Z
   CIMSS ADT: 59 KTS AT 041730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 25-30 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TROPICAL CYCLONE (TC) 14S IS FORECAST TO TRACK
GENERALLY WESTWARD THROUGH THE FORECAST PERIOD ALONG THE NORTHERN
PERIPHERY OF THE SUBTROPICAL RIDGE (STR). STEADY WEAKENING IS
EXPECTED THROUGH TAU 24 DUE TO THE PERSISTENT VERTICAL WIND SHEAR.
AFTER TAU 24, THE INTENSITY IS FORECAST TO REMAIN FLAT, WITH POSSIBLE
WEAKENING AFTER TAU 72 ASSOCIATED WITH COOLER SST VALUES UPWELLED
IN THE WAKE OF TC 13S. THE CURRENT EXTENDED FORECAST FOR TC 14S IS
EXPECTED TO TRACK DIRECTLY OVER THE AREA THAT TC 13S IS CURRENTLY
TRACKING.  

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT, 
WITH A 130-140NM CROSS-TRACK SPREAD IN SOLUTIONS FROM TAU 72 TO TAU 120. 
PROBABILISTIC GUIDANCE REVEALS A SIMILAR SPREAD OF SOLUTIONS LENDING 
HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. RELIABLE INTENSITY GUIDANCE 
INDICATES A LARGE SPREAD, WITH TWO DISTINCT CLUSTERS. HAFS-A AND COAMPS-
TC (GFS) INDICATE RAPID WEAKENING TO 40-45 KNOTS THEN A FLAT TREND 
THROUGH TAU 120. THE BULK OF THE GUIDANCE SHOWS WEAKENING THROUGH TAU 24 
TO ABOUT 65-70 KNOTS THEN SLIGHT RE-INTENSIFICATION AFTER TAU 96.  

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