WDXS32 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 13S (THIRTEEN) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.6S 97.1E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 204 NM SOUTH OF THE COCOS ISLANDS
   MOVEMENT PAST 6 HOURS: WESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A DEVELOPING
SYSTEM WITH THE CENTRAL DENSE OVERCAST SHEARED WESTWARD BUT
OBSCURING THE LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS
EXTRAPOLATED WITH MEDIUM CONFIDENCE FROM THE MICROWAVE LLC FEATURE
IN THE 021453Z AMSU-B IMAGE. THE INITIAL INTENSITY OF 45KTS, HELD
HIGHER THAN AGENCY AND AUTOMATED DVORAK ESTIMATES, IS ALSO PLACED
WITH MEDIUM CONFIDENCE. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT
WITH WARM SST AND STRONG POLEWARD OUTFLOW SLIGHTLY OFFSET BY
MODERATE VWS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SSE.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T2.5 - 35 KTS
   CIMSS SATCON: 46 KTS AT 021730Z
   CIMSS ADT: 41 KTS AT 021730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TC 13S WILL TRACK WEST-SOUTHWESTWARD IN THE
SOUTH INDIAN OCEAN UNDER THE STEERING STR. THE FAVORABLE
ENVIRONMENT WILL FUEL STEADY INTENSIFICATION TO 80 KTS BY TAU 120.

MODEL DISCUSSION: AVAILABLE NUMERICAL MODELS ARE IN VERY GOOD
AGREEMENT WITH A GRADUAL AND EVEN SPREAD TO 178NM BY TAU 72 THEN TO
304NM BY TAU 120. HOWEVER, GIVEN THE UNCERTAINTIES ASSOCIATED WITH
A DEVELOPING SYSTEM, THERE IS ONLY MEDIUM CONFIDENCE IN THE JTWC
TRACK AND INTENSITY FORECASTS. 

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