WDXS31 PGTW 290300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (DARIAN) WARNING 
NR 
024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.4S 73.7E
   INITIAL INTENSITY: 55 KNOTS
   GEOGRAPHIC REFERENCE: 600 NM EAST-SOUTHEAST OF PORT MATHURIN,
RODRIGUES
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 17 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) INDICATES THAT
WHILE THE PERIPHERAL BANDING REMAINS RAGGED, AN AREA OF CENTRAL
CONVECTION HAS STEADILY REBUILT OVER THE LOW LEVEL CIRCULATION
(LLC) AND EXPANDED OVER THE LAST 12 HOURS. A 282254Z SSMIS PASS
REVEALS THE DEEPEST CONVECTIVE ACTIVITY IS ISOLATED TO THE
SOUTHWEST QUADRANT, WITH TIGHTLY CURVED LOW LEVEL BANDING WRAPPING
INTO THE LLC. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE
BASED ON MULTI-AGENCY DVORAK FIXES AND SUPPORTED BY THE
AFOREMENTIONED SSMIS DATA. WIND ESTIMATES FROM SMAP, SMOS, AND RCM
SAR PASSES EARLIER IN THE DAY ALL CONVERGED ON A 55 KNOT INTENSITY
VALUE. DESPITE NOW TRACKING OVER 24-25 DEGREE WATERS, WANING
OUTFLOW, AND BEING NEARLY ENCOMPASSED BY MID-LEVEL DRY AIR,
TC DARIAN CONTINUES ITS LONG-TIME TREND OF DEFYING EXPECTATIONS,
LOGIC, AND CONVENTIONAL WISDOM. THE INITIAL INTENSITY FOR THIS
CYCLE WAS HELD AT 55 KNOTS, WITH DVORAK FINAL INTENSITY ESTIMATES
FROM PGTW AND KNES COMING UP TO T3.5 (55 KNOTS) AS THE CORE
CONVECTION REINVIGORATED. AUTOMATED TECHNIQUES REMAIN STUBBORNLY
LOW-BIASED, HOWEVER, 282003Z SATCON WAS 52 KNOTS.

INITIAL WIND RADII BASIS: 282037Z AMSR2 WINDS AND EARLIER
SCATTEROMETER DATA.


CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE SOUTHEAST 


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS SATCON: 52 KTS AT 282003Z
   CIMSS ADT: 39 KTS AT 290015Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 10-15 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: MID-LEVEL DRY AIR WRAPPING ALMOST COMPLETELY AROUND 
THE LLC


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: THE CURRENT ORIENTATION OF THE STR SHOULD
ALLOW TC DARIAN TO CONTINUE ON ITS CURRENT SOUTHWESTERLY TRACK FOR
THE NEXT 36 HOURS BY WHICH POINT IT IS EXPECTED TO BE FULLY
SUBTROPICAL. AFTER TAU 36, TC DARIAN SHOULD FINALLY BEGIN TO ROUND
THE STR AND BEGIN EXTRA-TROPICAL TRANSITION (ETT). WHILE IN MANY
WAYS DARIAN IS ONE FOR THE RECORD BOOKS, ETT WILL BE COMPLETE BY
TAU 72, FINALLY BRINGING AN END TO ITS TENACIOUS SPIRIT AS THE
CALENDAR YEAR CLOSES OUT. THE ALIGNMENT AND PROXIMITY OF A TROUGH
TO THE WEST SHOULD PROVIDE BAROCLINIC ASSISTANCE IN MAINTAINING GALE
FORCE WINDS THROUGHOUT THE TRANSITION. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT,
LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. THERE IS, 
HOWEVER, ONLY MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST DUE
TO THE TIMING OF ETT AND THE DEGREE OF BAROCLININC FORCING AT PLAY. 


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