WDXS33 PGTW 122100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (TALIAH) WARNING NR 
024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.2S 89.6E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 638 NM SOUTHWEST OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 33 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 14S (TALIAH) WITH A LARGE AND RAGGED EYE FEATURE, AS
WELL AS A LOOSELY ORGANIZED SPIRAL BANDS OF DEEP CONVECTION
WRAPPING INTO THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE SYSTEM
SHOWS SIGNS OF WEAKENING, AS ENVIRONMENTAL ANALYSIS REVEALS MORE
DRY AIR SURROUNDING THE VORTEX, OFFSET BY MODERATE POLEWARD
OUTFLOW, LOW (5-10KTS) VERTICAL WIND SHEAR, AND WARM (26-27C)
SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON RAGGED EYE PRESENT IN THE ANIMATED SHORTWAVE
INFRARED IMAGERY. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE
INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: 121231Z RCM-2 SAR DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) POSITIONED TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.5 - 77 KTS
   CIMSS ADT: 51 KTS AT 121800Z
   CIMSS AIDT: 53 KTS AT 121915Z
   CIMSS D-PRINT: 61 KTS AT 121915Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   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 14S IS FORECAST TO TRACK SOUTHWESTWARD
ALONG THE WESTERN PERIPHERY OF A STRONG, DEEP-LAYER STR TO THE EAST
THROUGHOUT THE FORECAST PERIOD. THE ENVIRONMENTAL CONDITIONS WILL
VERY SLOWLY BECOME LESS FAVORABLE, AS THERE IS GOING TO BE MORE DRY
AIR SURROUNDING THE VORTEX, EVENTUALLY WRAPPING INTO THE CORE OF
THE SYSTEM. OTHER FACTORS REMAIN MARGINALLY FAVORABLE, WITH
BORDERLINE (25-26C) SEA SURFACE TEMPERATURES (SST), LOW TO
MODERATE (15-20KTS) VERTICAL WIND SHEAR (VWS) AND GOOD POLEWARD
OUTFLOW. AROUND TAU 120 THE CONDITIONS WILL HOWEVER BEGIN TO
DEGRADE, WITH SSTS DROPPING BELOW 24C.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT IN
REGARDS TO THE FIRST 72 HOURS OF THE TRACK ASSESSMENT, WITH
CROSS-TRACK SPREAD OF 75NM. AFTER THAT, THE MODEL TRACKERS SPREAD
OUT SIGNIFICANTLY TO OVER 400NM BY THE END OF THE FORECAST PERIOD,
INDICATING HIGH UNCERTAINTY IN REGARD TO NOT ONLY THE STEERING
PATTERN, BUT ALSO INTENSITY OF THE SYSTEM. JTWC FORECAST TRACK IS
THEREFORE ASSESSED WITH HIGH CONFIDENCE THROUGH TAU 72 AND MEDIUM
AFTERWARDS. INTENSITY GUIDANCE REMAINS IN FAIR AGREEMENT OVER THE
INITIAL 72 HOURS AND THE JTWC INTENSITY IS ASSESSED WITH MEDIUM
CONFIDENCE, JUST ABOVE THE MULTI-MODEL CONSENSUS. AFTER TAU 72
HOWEVER, INTENSITY GUIDANCE CONFIDENCE IS LOW, DUE TO COAMPS-TC AND
GFS SHOWING A SLIGHT UPTICK IN MAXIMUM WIND SPEEDS, WHILE THE OTHER 
AIDS SHOW CONTINUOUS AND STEADY WEAKENING. JTWC INTENSITY GUIDANCE IS 
ASSESSED CLOSE, BUT SLIGHTLY ABOVE THE MULTI-MODEL CONSENSUS, HEDGED 
TOWARDS THE GFS AND COAMPS-TC FORECAST.

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