WDXS33 PGTW 082100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (TALIAH) WARNING NR 
016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.7S 94.7E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 246 NM SOUTH-SOUTHWEST OF THE COCOS
ISLANDS
   MOVEMENT PAST 6 HOURS: WESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 29 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS PERSISTENT
CONVECTION LOCATED ON THE NORTHERN EDGE OF TROPICAL CYCLONE (TC)
14S (TALIAH). WHILE THE CLOUD TOPS VISIBLE IN THE MSI DO NOT
ORGANIZE TIGHTLY JUST YET, THE ASSOCIATED CONVECTIVE BANDING
VISIBLE IN THE 081525Z METOPC AMSU 89 GHZ MICROWAVE IMAGERY DEPICTS
A DEVELOPING AND ORGANIZING STRUCTURE OF THE CORE OF THE SYSTEM.
THE INITIAL POSITION IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON
EXTRAPOLATION FROM THE AFOREMENTIONED MICROWAVE IMAGE IN
CONJUNCTION WITH THE 081433Z METOP-B ASCAT IMAGE. THE INITIAL
INTENSITY OF 45 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE
OLDER, 081200Z RCM-2 SAR PASS, CONSISTENT WITH THE AFOREMENTIONED
ASCAT IMAGE, BOTH SHOWING A SWATH OF 35 KT WINDS TO THE NORTH OF
THE ASSESSED LOW-LEVEL CIRCULATION CENTER (LLCC).

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: NORTHEASTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED TO THE SOUTHWEST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 45 KTS AT 081518Z
   CIMSS ADT: 51 KTS AT 081730Z
   CIMSS D-PRINT: 41 KTS AT 081800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   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 IS FORECAST TO START TURNING
WEST-NORTHWESTWARD, DUE TO A BUILDING SUBTROPICAL RIDGE (STR)
LOCATED CURRENTLY TO THE SOUTHWEST OF THE SYSTEM, BETWEEN 13S AND
14S. THIS STEERING MECHANISM WILL REMAIN IN PLACE OVER THE NEXT 48
HOURS, KEEPING THE TC TALIAH WITHIN A REGION OF MARGINALLY
FAVORABLE ENVIRONMENTAL CONDITIONS. THE SEA SURFACE TEMPERATURES
ARE FORECAST TO REMAIN ABOVE 27C, WITH MODERATE VERTICAL WIND SHEAR
OF 15-20 KTS, ALLOWING TC 14S KEEP INTENSIFYING. PAST TAU 48 THE
STR WILL RAPIDLY WEAKEN, REORIENT, AND MOVE THE EAST. THIS ALLOWS
TC 14S TO BEGIN A SOUTHWESTWARD TURN, NOW BEING DRIVEN BY THE
BUILDING RIDGE DIRECTLY TO THE EAST, COMING OFF THE COAST OF
WESTERN AUSTRALIA. TOWARDS THE END OF THE FORECAST PERIOD HOWEVER,
TC 14S IS FORECAST TO BEGIN WEAKENING, WHILE IT ENCOUNTERS LESS
FAVORABLE CONDITIONS, INCLUDING RAPIDLY DROPPING SEA SURFACE
TEMPERATURES (DOWN TO 25-26 BY TAU 120), INCREASING SHEAR, AND
INCREASINGLY DRY AIR SURROUNDING THE SYSTEM.

MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IS IN FAIR OVERALL
AGREEMENT IN REGARDS TO THE GENERAL STEERING PATTERNS DETERMINING
THE NORTHWESTWARD TURN, FOLLOWED BY A POLEWARD TRACK SHIFT. AT THE
SAME TIME CROSS-TRACK AND ALONG-TRACK SPREADS REMAIN HIGH BETWEEN
THE GUIDANCE. THIS LEADS TO ELEVATED UNCERTAINTY IN REGARD TO THE
TIMELINE AND SHARPNESS OF EACH TURN, WITH OUTLYING GALWEM AND UKMET 
PREDICTING A SHARPER, NEARLY NORTHWARD TURN AT TAU 12. MEANWHILE, 
OTHER GUIDANCE SHOWS A MORE GRADUAL CORNERING. HIGH INITIAL 
UNCERTAINTY LEADS TO A NEARLY 150 NM CROSS-TRACK SPREAD AT TAU 72, 
EXPANDING TO OVER 300 NM SPREAD BY TAU 120. SIMILARLY, THE INTENSITY 
GUIDANCE UNCERTAINTY REMAINS RELATIVELY HIGH AS WELL, MAINLY DUE TO 
THE DIFFERENCES IN TRACK ASSESSMENT. HOWEVER, THE MAJORITY OF MODELS 
SUGGEST A STEADY INTENSIFICATION THROUGHOUT THE FIRST 96 HOURS, 
FOLLOWED BY IMMEDIATE WEAKENING. COAMPS-TC RI ENSEMBLE IN THE MEANTIME 
SHOWS A 20 PERCENT RI PROBABILITY BY TAU 60, INCREASING TO 40 PERCENT 
TOWARDS THE END OF THE FORECAST PERIOD, DRIVEN MAINLY BY A SLIGHTLY 
MORE WESTWARD TRACK, KEEPING THE VORTEX WITHIN A FAVORABLE ENVIRONMENT 
FOR A LONGER PERIOD. JTWC INTENSITY TRACK GUIDANCE IS LAID IN CLOSE 
PROXIMITY TO THE MULTI-MODEL CONSENSUS, LEANING CLOSER TO THE GRADUAL 
INITIAL TURNING. JTWC INTENSITY ESTIMATE IS ALSO PLACED CLOSE TO THE 
MULTI-MODEL CONSENSUS.

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