WDXS31 PGTW 182100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 08S (CHENESO)    
WARNING NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.5S 51.7E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 404 NM NORTHEAST OF ANTANANARIVO,
MADAGASCAR
   MOVEMENT PAST 6 HOURS: WESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
RAPIDLY CONSOLIDATING SYSTEM WITH A CENTRAL DENSE OVERCAST FEATURE 
OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC). THIS IMPROVEMENT
IS EVIDENT IN AN 181418Z SSMIS 91GHZ MICROWAVE IMAGE, WHICH REVEALS
A COMPACT CORE SURROUNDING A SMALL MICROWAVE EYE FEATURE AND DEEP
CONVECTIVE BANDING OVER THE WESTERN SEMICIRCLE. OVERALL
ENVIRONMENTAL CONDITIONS ARE FAVORABLE WITH ROBUST POLEWARD
OUTFLOW, LOW TO MODERATE VERTICAL WIND SHEAR AND WARM SST VALUES.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
SSMIS IMAGE. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE KNES AND FMEE DVORAK ESTIMATES AS WELL AS A
TIMELY 181432Z SMAP IMAGE SHOWING 58 KNOT (1-MINUTE AVERAGE) WINDS
OVER THE NORTHERN QUADRANT.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) POSITIONED TO
THE SOUTH AND SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   NFFN: T4.0 - 65 KTS
   CIMSS ADT: 47 KTS AT 181815Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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) 08S IS TRACKING ALONG
THE NORTHERN PERIPHERY OF THE STR AND IS FORECAST TO MAKE LANDFALL
OVER NORTHEASTERN MADAGASCAR WITHIN THE NEXT 12 HOURS. DUE TO
FAVORABLE CONDITIONS, TC 08S WILL CONTINUE TO INTENSIFY PRIOR TO
LANDFALL TO A PEAK OF 60-65 KNOTS. THE STR IS EXPECTED TO REALIGN
TO THE EAST WHICH WILL TURN THE SYSTEM SOUTH-SOUTHWESTWARD AS IT
TRACKS OVER THE MOUNTAINOUS TERRAIN OF MADAGASCAR. CONSEQUENTLY, THE
SYSTEM WILL WEAKEN RAPIDLY AND DISSIPATE BY TAU 36. AFTER TAU 36,
THE SYSTEM WILL STALL OVER MADAGASCAR DUE TO COMPETING STEERING
INFLUENCES AND WILL CONTINUE TO WEAKEN RAPIDLY.
   
MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 24 THEN DIVERGES WITH INCREASING UNCERTAINTY IN THE
TRACK. THE MAJORITY OF THE TRACK GUIDANCE KEEPS THE REMNANTS
OVERLAND, HOWEVER, THE 181200Z ECMWF (EPS) ENSEMBLE INDICATES SOME
POTENTIAL FOR THE REMNANTS TO MOVE BACK OVER WATER AFTER THREE
DAYS.   

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