WDXS31 PGTW 232100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 22S (HORACIO) WARNING 
NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.7S 65.1E
   INITIAL INTENSITY: 140 KTS
   GEOGRAPHIC REFERENCE: 440 NM EAST OF PORT LOUIS, MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 22S (HORACIO) CONTINUES TO TRACK SOUTH
SOUTHWESTWARD UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE OVER THE
CENTRAL INDIAN OCEAN. THE SYSTEM RETAINS A HIGHLY SYMMETRICAL
STRUCTURE WITH STRONG RADIAL OUTFLOW. CLOUD TOP TEMPERATURES HAVE
STARTED WARMING AND THE EYE DIAMETER MEASURES 10 NM AS DEPICTED BY
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY. A 231407Z RCM-3
SAR PASS REVEALED A MEAN INTENSITY OF 114 KNOTS AND A PEAK INTENSITY 
OF 121 KNOTS. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE WITH WARM SEA 
SURFACE TEMPERATURES (27 C TO 28 C), LOW VERTICAL WIND SHEAR (10-15 
KTS), AND STRONG RADIAL OUTFLOW. THE INITIAL POSITION IS ASSESSED WITH
HIGH CONFIDENCE BASED ON ANIMATED EIR IMAGERY OF THE EYE FEATURE.
THE INITIAL INTENSITY OF 140 KTS IS ASSESSED WITH HIGH CONFIDENCE
BASED ON THE EARLIER 231407Z SAR PASS ALONG WITH OBJECTIVE AND
SUBJECTIVE ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: 231407Z SAR DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) CENTERED TO THE
EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T7.0 - 140 KTS 
   DEMS: T7.0 - 140 KTS 
   FIMP: T7.0 - 140 KTS 
   CIMSS SATCON: 125 KTS AT 231444Z
   CIMSS ADT: 137 KTS AT 231830Z
   CIMSS AIDT: 138 KTS AT 231830Z
   CIMSS D-MINT: 115 KTS AT 231443Z
   CIMSS D-PRINT: 118 KTS AT 231830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 22S WILL CONTINUE A GENERALLY SOUTHWARD
TRACK AS IT FINISHES ROUNDING THE AXIS OF THE SUBTROPICAL RIDGE
(STR) OVER THE CENTRAL INDIAN OCEAN OVER THE NEXT 24 HOURS.
AFTERWARDS THE SYSTEM WILL BE STEERED SOUTHEASTWARD BY THE STR INTO
AN A PROGRESSIVELY UNFAVORABLE VERTICAL WIND SHEAR (VWS)
ENVIRONMENT (15 TO 30+ KTS). THE NEW VWS ENVIRONMENT ALONG WITH
COOLING SEA SURFACE TEMPERATURES BENEATH THE CIRCULATION AND
PROXIMITY TO THE JET WILL RESULT IN A DECOUPLING OF THE VORTEX AND
A STEEP WEAKENING THROUGH THE REMAINDER OF THE FORECAST PERIOD. THE
SYSTEM WILL BEGIN SUBTROPICAL TRANSITION (STT) AROUND TAU 96, WITH
COMPLETION EXPECTED BY THE END OF THE FORECAST. 


MODEL DISCUSSION: MODEL GUIDANCE IS IN STRONG AGREEMENT WITH
MINIMAL CROSS- OR ALONG-TRACK UNCERTAINTY. THE JTWC FORECAST IS
PLACED NEAR THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE THROUGH
TAU 72 AND MEDIUM CONFIDENCE THEREAFTER. INTENSITY GUIDANCE IS
SIGNIFICANTLY SPREAD WITH HAFS-A SHOWING A MORE GRADUAL DECREASE IN
INTENSITY AS OPPOSED TO THE SHARPER DROP AMONG THE MAJORITY OF THE
OTHER GUIDANCE MEMBERS. THE JTWC FORECASTED INTENSITY REFLECTS
VALUES SLIGHTLY BELOW THE CONSENSUS ACCOUNTING FOR THE EXPECTED
RAPIDLY DETERIORATING ENVIRONMENTAL CONDITIONS. THE FORECASTED
INTENSITY IS PLACED WITH HIGH CONFIDENCE UNTIL TAU 72 AND MEDIUM
CONFIDENCE AFTERWARD. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: HIGH
   INTENSITY 72-120 HR: MEDIUM//
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