WDXS31 PGTW 300300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (DARIAN) WARNING 
NR 026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.1S 70.2E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 797 NM EAST-SOUTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS LIMITED
CONVECTION PERSISTING NEAR THE CENTER AND TO THE SOUTH OF A
BROADENING AND MOSTLY EXPOSED LOW-LEVEL CIRCULATION. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED PRIMARILY ON A 292240Z 
SSMIS PASS AND A PARTIALLY-EXPOSED CENTER EVIDENT IN MULTISPECTRAL 
SATELLITE IMAGERY. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH 
MEDIUM CONFIDENCE BASED ON A 47 KNOT 292035Z SATCON ESTIMATE, 
SLIGHTLY ABOVE SUBJECTIVE DVORAK ESTIMATES GIVEN A TRENDING LOW BIAS 
IN THOSE ESTIMATES OVER THE PAST SEVERAL ANALYSIS CYCLES. TC 05S IS 
WEAKENING VERY SLOWLY AS IT MOVES OVER COOLER WATER AND INTO AN AREA 
OF INCREASING VERTICAL WIND SHEAR.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   FMEE: T2.5 - 35 KTS
   CIMSS SATCON: 47 KTS AT 292035Z
   CIMSS ADT: 33 KTS AT 292115Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 20-25 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: MODERATE EASTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE PREDICTED TIMING OF SUBTROPICAL
AND EXTRATROPICAL TRANSITION HAS BEEN DELAYED BY 12 HOURS.
HOWEVER, THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE
PREVIOUS WARNING.

FORECAST DISCUSSION: TC 05S WILL ROUND THE STEERING RIDGE THROUGH
THE FORECAST PERIOD. THE SYSTEM WILL COMPLETE SUBTROPICAL
TRANSITION AS IT TURNS POLEWARD AND INTERACTS WITH A SHORTWAVE
TROUGH APPROACHING FROM THE WEST OVER THE NEXT 24 HOURS. AFTER TAU
24, THE SYSTEM WILL TURN GRADUALLY TOWARD THE SOUTHEAST AS IT 
APPROACHES THE MID-LATITUDE WESTERLIES AND UNDERGOES EXTRATROPICAL 
TRANSITION. BY TAU 72, TC 05S WILL BE AN EXTRATROPICAL LOW, FULLY 
EMBEDDED IN THE WESTERLY FLOW PATTERN. STORM INTENSITY IS EXPECTED TO 
REMAIN IN THE WEAK TROPICAL STORM RANGE THROUGHOUT THE UPCOMING PHASE 
TRANSITIONS AS FAVORABLY BAROCLINIC SUPPORT OFFSETS THE NEGATIVE 
IMPACTS OF PASSAGE OVER COOLER WATER AND INCREASING VERTICAL WIND 
SHEAR.

MODEL DISCUSSION: NUMERICAL MODEL TRACK FORECAST GUIDANCE REMAINS
IN EXCELLENT AGREEMENT THROUGH TAU 72, AND THE CURRENT FORECAST
LIES CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.
DYNAMIC MODELS PREDICT A SLOW BUT STEADY WEAKENING TREND CONSISTENT
WITH THE CURRENT INTENSITY FORECAST, WHICH IS ALSO SET WITH HIGH
CONFIDENCE.

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