WDXS31 PGTW 251500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 08S (CHENESO)    
WARNING NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.9S 42.9E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 205 NM NORTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 01 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 08S HAS REMAINED QUASI-STATIONARY WITH SLOW- 
ERRATIC MOTION OVER THE PAST 12 HOURS AND HAS WEAKENED SLIGHTLY DUE 
TO THE UPWELLING OF COOLER WATER AS WELL AS INTERACTION WITH LAND 
OVER THE EASTERN SEMICIRCLE. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
(MSI) DEPICTS TIGHTLY CURVED BANDING WRAPPING INTO A RAGGED, CLOUD-
FILLED EYE. A 251122Z GMI 89GHZ MICROWAVE IMAGE REVEALS A WEAK 
EYEWALL SURROUNDING A LARGE 30-35NM DIAMETER MICROWAVE EYE, WHICH 
SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE AND EXTENSIVE DEEP
CONVECTIVE BANDING. A 250244Z SENTINEL 1 SAR BULLSEYE IMAGE WAS
USED TO ADJUST THE WIND RADII AND SHOWED MAXIMUM WINDS OF 67 KNOTS
OVER THE SOUTHWEST QUADRANT. THE SYSTEM APPEARS TO HAVE PEAKED AT
75 KNOTS AT 250600Z AND HAS SUBSEQUENTLY WEAKENED TO 70 KNOTS BASED
ON THE DVORAK CURRENT INTENSITY ESTIMATES AS WELL AS THE RECENT ADT
ESTIMATE.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: COMPETING STEERING PATTERN WITH A
NEAR-EQUATORIAL RIDGE POSITIONED TO THE NORTH AND A SUBTROPICAL
RIDGE ENTRENCHED TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.0 - 65 KTS
   FMEE: T4.5 - 77 KTS
   CIMSS ADT: 69 KTS AT 251200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-30 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: UPWELLING COOL WATER AND INTERACTION WITH LAND
OVER THE EASTERN SEMICIRCLE OF THE SYSTEM

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 08S SHOULD REMAIN QUASI-STATIONARY THROUGH
24 WITHIN THE COMPETING STEERING PATTERN WITH UPWELLING COOL WATER
EXPECTED TO SLOW INTENSIFICATION. ADDITIONALLY, INTERACTION WITH
LAND WILL ALSO HINDER SIGNIFICANT INTENSIFICATION. AFTER TAU 24, THE 
STR TO THE SOUTH IS EXPECTED TO GRADUALLY WEAKEN WITH THE APPROACH OF 
A DEEP UPPER-LEVEL TROUGH WHICH WILL SHIFT THE STR TO THE EAST AND 
ALLOW TC 08S TO ACCELERATE POLEWARD. TC 08S WILL PEAK AT 100 KNOTS 
NEAR TAU 48 AS IT TRACKS OVER WARMER WATER AND OUTFLOW VENTS INTO THE 
WESTERLIES TO THE SOUTH. THE STR WILL GRADUALLY STRENGTHEN TO THE 
EAST DRIVING TC 08S SOUTHWARD THEN EVENTUALLY SOUTHEASTWARD AFTER TAU 
72 WHEN THE SYSTEM ROUNDS THE STR AND BEGINS TO INTERACT WITH THE 
SUBTROPICAL WESTERLIES.    

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL GUIDANCE
IS IN GOOD AGREEMENT SUPPORTING THE INITIAL QUASI-STATIONARY PHASE 
AND EVENTUAL POLEWARD ACCELERATION. THE ECMWF ENSEMBLE (EPS) AND GFS 
ENSEMBLE (GEFS) ARE IN GOOD AGREEMENT AS WELL BUT INDICATE INCREASING 
ALONG-TRACK UNCERTAINTY DURING THE RECURVE PORTION OF THE TRACK SOUTH 
AND SOUTHEAST OF MADAGASCAR. THE COAMPS-TC ENSEMBLE (250600Z) 
INDICATES A 20-40 PERCENT PROBABILITY OF MODERATE INTENSIFICATION IN 
THE TAU 60 TO TAU 96 PERIOD.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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