WDXS32 PGTW 230300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16S (ELEANOR) WARNING 
NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.3S 57.5E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 132 NM SOUTH OF PORT LOUIS, MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 16S (ELEANOR) EXPERIENCING SIGNIFICANT VERTICAL WIND
SHEAR (VWS) FROM THE NORTHWEST, RESULTING IN FLARING CONVECTION
BEING PUSHED OFF TO THE SOUTHEAST OF THE LOWER LEVEL CIRCULATION
CENTER (LLCC). ANALYSIS OF EARLIER SSMIS MICROWAVE IMAGERY SUGGESTS
A MODERATE AMOUNT OF VORTEX TILT IN THE SAME DIRECTION. DRY AIR
ENTRAINMENT FROM THE NORTHWEST CONTRIBUTES TO A UNFAVORABLE 
ENVIRONMENT AS IT CONTINUES TO ENGULF THE SYSTEM. FAVORABLE OUTFLOW 
ENCOURAGED BY A JET MAXIMUM TO THE SOUTHWEST AND FAVORABLE SEA SURFACE 
TEMPERATURES OF 27-28C, ARE OFFSETTING THE STRONG (30 KNOTS OR 
GREATER) NORTHWESTERLY SHEAR, PREVENTING RAPID DEGRADATION OF THE 
SYSTEM AT THE MOMENT. THE INITIAL POSITION WAS ASSESSED WITH LOW 
CONFIDENCE USING SHORTWAVE INFRARED (SWIR) IMAGERY, PARTIALLY 
REVEALING AN LLCC ON THE NORTHWEST EDGED OF THE CIRRUS SHIELD. THE 
INITIAL INTENSITY WAS ALSO ASSESSED WITH LOW CONFIDENCE, BASED ON
SUBJECTIVE AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: THE NORTHERN PERIPHERY OF A TRANSITORY,
MID-LATITUDE RIDGE TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   FMEE: T3.5 - 55 KTS
   FIMP: T3.5 - 55 KTS
   CIMSS SATCON: 53 KTS AT 222123Z
   CIMSS ADT: 53 KTS AT 230000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 30+ KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: TC 16S IS ANTICIPATED TO FULLY
DISSIPATE TO 30KTS BY TAU 48. 

FORECAST DISCUSSION: TC 16S IS FORECAST TO TRACK TO THE
SOUTH-SOUTHWEST AS IT SLOWS TO 5KTS OVER THE NEXT 12 HOUR AS THE
VORTEX SHALLOWS OUT DUE TO STRONG NORTHWESTERLY SHEAR AND IT IS
ENGULFED BY DRY AIR ABOVE 700MB. ONCE THE DECOUPLING PROCESS IS
COMPLETE AROUND TAU 12, AND THE VORTEX BECOMES SHALLOWER, IT IS
EXPECTED TO COMMENCE A WEST-NORTHWESTERLY TRACK AS IT COMES UNDER
THE INFLUENCE OF A LOWER-LEVEL RIDGE TO THE SOUTHWEST. A GENERAL
WEST-NORTHWEST TRACK MOTION IS ANTICIPATED THROUGH THE END OF THE
FORECAST PERIOD. THE SYSTEM INTENSITY IS EXPECTED TO STEADILY
DECLINE FROM 50KTS, TO 30 KNOTS OR LESS BY TAU 48 AS A RESULT OF THE
SIGNIFICANT VWS AND LARGE AMOUNTS OF DRY AIR COMPLETELY WRAPPING
INTO THE SYSTEM.  

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT TROPICAL CYCLONE 16S WILL TURN FROM A SOUTH-SOUTHWESTERLY
TRACK TO A WEST-NORTHWESTERLY TRACK AROUND TAU 12. JTWC CONSENSUS
MODEL GUIDANCE HAS MINIMAL CROSS-TRACK ERROR, ONLY OPENING TO 120NM
BY TAU 48. JTWC INTENSITY CONSENSUS GUIDANCE ALSO IS IN GOOD
AGREEMENT THAT THE SYSTEM WILL WEAKEN THROUGHOUT THE REMAINDER OF
THE FORECAST PERIOD, THE EXCEPTION OF COAMPS-TC WHICH EXPECTS A
LOWER RATE OF WEAKENING INITIALLY BUT STILL ARRIVES AT 30 KNOTS BY
TAU 48. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   INTENSITY 0 - 72 HR: LOW//
NNNN