WDXS31 PGTW 130300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FIVE) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.5S 55.8E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 347 NM NORTH-NORTHWEST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS CONTINUED
INTENSIFICATION AND RAPID CONSOLIDATION, WITH INCREASINGLY
ORGANIZED CONVECTIVE SPIRAL BAND WRAPPING INTO A WELL-DEFINED LOW
LEVEL CIRCULATION CENTER (LLCC). THROUGHOUT THE LAST SIX HOURS,
DEEP CONVECTIVE STRUCTURES HAVE CONTINUOUSLY DEVELOPED ALONG THE
SOUTHERN AND WESTERN PERIPHERIES, WHILE UPPER-LEVEL CIRRUS BLOW OFF
EJECTS BOTH EQUATORWARD AND POLEWARD, ALLOWING FOR SUPPORTIVE
DUAL-CHANNEL DIVERGENCE ALOFT. THE INITIAL POSITION IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON SLIGHT NOTCHING OBSERVED IN THE
122206Z ADVANCED TECHNOLOGY MICROWAVE SOUNDER (ATMS) IMAGERY AND IN
THE ANIMATED MSI. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE RAPID AND CONTINUED ORGANIZATION OF
THE CONVECTIVE BANDING AND THE T3.0 DVORAK CURRENT INTENSITY
ESTIMATES FROM PGTW. ANALYSIS SHOWS A VERY FAVORABLE ENVIRONMENT,
CHARACTERIZED BY LOW (5-10 KNOTS) OF EASTERLY SHEAR, THE
AFOREMENTIONED DUAL-CHANNEL FLOW, AND WARM SSTS. THE SYSTEM IS
CURRENTLY MOVING TO THE SOUTHWEST ALONG THE SUBTROPICAL RIDGE (STR)
CENTERED DIRECTLY TO THE EAST.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A STR CENTERED TO
THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T2.5 - 35 KTS
   DEMS: T2.5 - 35 KTS
   CIMSS SATCON: 40 KTS AT 121913Z
   CIMSS ADT: 37 KTS AT 122100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG DUAL-CHANNEL

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: TROPICAL CYCLONE (TC) 05S (FIVE) IS FORECAST
TO TRACK TOWARD THE SOUTHWEST ALONG THE WESTERN PERIPHERY OF THE
STEERING SUBTROPICAL RIDGE FOR THE NEXT 24 HOURS. TRACK SPEED IS
EXPECTED TO REMAIN FAIRLY STEADY AS THE RIDGE DRIVES THE STORM
TRACK TOWARD MAURITIUS AND LA REUNION. BY TAU 24, THE OVERALL
MOVEMENT BEGINS TO PROGRESS SOUTHWARD AND SLOWS DOWN AS THE
STEERING RIDGE REORIENTS TO THE NORTHEAST. BY TAU 36, TC 05S WILL
BEGIN ITS SOUTHEASTWARD TRACK AND IS EXPECTED TO PASS DIRECTLY IN
BETWEEN MAURITIUS AND LA REUNION NEAR THE TAU 72, AND CONTINUE INTO
THE OPEN WATERS OF THE INDIAN OCEAN. THE ENVIRONMENT REMAINS
FAVORABLE FOR ONGOING RAPID INTENSIFICATION AS DESTRUCTIVE VERTICAL
WIND SHEAR (VWS) REMAINS LOW AND ALLOWS FOR INTENSITY TO INCREASE
TO 60 KNOTS WITHIN THE NEXT 12 HOURS. 105 KNOTS IS FORECAST INTO
TAU 72 AS WELL WHILE THE ENVIRONMENT SUPPORTS CONTINUED
STRENGTHENING DIRECTLY THROUGH THE MASCARENE ARCHIPELAGO. AN
EXPECTED RAPID DECREASE IN OCEAN HEAT CONTENT AND SSTS, WHILE VWS
INCREASES WILL INDUCE A WEAKENING OF 05S INTO TAU 120 AS THE STORM
PROGRESSES POLEWARD TOWARD COOLER WATERS. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE REMAINS IN GOOD
OVERALL AGREEMENT THROUGH THE FIRST 60 HOURS OF THE FORECAST
PERIOD. ALL MODEL GUIDANCE EXCEPT NAVGEM, WHICH IS FURTHER TO THE
NORTHEAST, IS CONFINED TO A 70-75NM ENVELOPE THROUGH TAU 72. THE
JTWC FORECAST REMAINS WEST OF THE CONSENSUS MEAN AND CONSISTENT
WITH THE ECMWF AND GFS TRACKER THROUGH TAU 72 WITH MEDIUM
CONFIDENCE. INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT THE SYSTEM
WILL CONTINUE TO RAPIDLY INTENSIFY (RI), WITH MULTIPLE RI AIDS
VERIFYING. ALL MEMBERS OF THE OF THE CONSENSUS AGREE ON A LEVELING
OFF OF STORM INTENSITY AFTER TAU 60, FOLLOWED BY SLOW, BUT STEADY
WEAKENING BY THE END OF THE FORECAST PERIOD AS 05S MOVES INTO OPEN
WATERS. THE JTWC FORECAST TRACKS ABOVE MOST OF THE GUIDANCE THROUGH
THE NEXT 72 HOURS, THEN TRACKS INTO THE CONSENSUS NEAR THE MEAN
AFTER TAU 108. 

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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