WDXS31 PGTW 250300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 08S (CHENESO) WARNING 
NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.1S 43.0E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 201 NM NORTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: EASTWARD AT 01 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SCATTEROMETRY
AND MICROWAVE IMAGERY OVER THE PAST 12 HOURS CONFIRMS THAT TROPICAL
STORM 08S (CHENESO) IS INTENSIFYING SLOWLY BUT STEADILY AS IT
MEANDERS OFF THE EAST COAST OF MADAGASCAR. THE SYSTEM HAS DEVELOPED
AN EYE ON TWO OCCASIONS DURING THE PAST 24 HOURS WITH THE LATEST
OCCURENCE PERSISTING AT BULLETIN ISSUE TIME. UPWELLING INDUCED BY
THE NON-MOVEMENT OF CHENESO AND LAND INTERACTION OVER THE EASTERN 
PERIPHERY IS DEFINITELY ACTING AS A BREAKING MECHANISM ON 
INTENSIFICATION DESPITE THE NEAR PERFECT ENVIRONMENT. 
THE SYSTEM IS ENTERING THE DIURNAL MAX PHASE YET NOT JUMPING IN 
INTENSITY PROVIDING FURTHER EVIDENCE OF THE UPWELLING. ANIMATED WATER 
VAPOR IMAGERY SHOWS THE SYSTEM IS WELL ENSCONSED FROM THE SUBSIDENCE 
AND DRIER AIR TO THE DISTANT SOUTHWEST. THE WATER VAPOR ALSO SHOWS 
SPECTACULAR EQUATORIAL OUTFLOW AND A VIGOROUS POLEWARD OUTFLOW 
CHANNEL. A MID-HIGH LEVEL RIDGE EXTENDING FROM THE EASTERN ATLANTIC 
ACROSS THE KALAHARI DESERT AND INTO THE SOUTHWEST INDIAN OCEAN IS 
COMBINING WITH THE NEAR EQUATORIAL RIDGE TO TRAP THE SYSTEM IN AN 
ENVIRONMENT CHARACTERIZED BY 29-30C DEGREE SEA WATERS, LESS THAN 10 
KNOTS OF VERTICAL WIND SHEAR, AND OUTSTANDING OUTFLOW. UPWELLING IS 
THE ONLY FACTOR KEEPING CHENESO FROM TURNING INTO A MONSTER. THE 
CURRENT INTENSITY ESTIMATE COMBINES THE JTWC AND FMEE DVORAKS WITH 
THE NEW CIMSS DEEP MICRONET INTENSITY ESTIMATOR AND THE OPEN-AIIR 
SYSTEM, WHICH HAVE BEEN DOING AN OUTSTANDING JOB WITH THE STORM OVER 
THE PAST 24 HOURS.

INITIAL WIND RADII BASIS: A DIRECT OVERHEAD 25KM ASCAT PASS AT
241831Z. 

CURRENT STEERING MECHANISM: THERE IS NO STEERING MECHANISM. THE
SYSTEM IS TRAPPED BETWEEN THE NEAR EQUATORIAL RIDGE AND THE
SUBTROPICAL RIDGE. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.0 - 65 KTS
   FMEE: T4.0 - 65 KTS
   CIMSS SATCON: 70 KTS AT 242227Z
   CIMSS ADT: 72 KTS AT 250000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: -1-0 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: TC 08S WILL WOBBLE LIKE A SAILOR TRYING TO GET
BACK TO THE SHIP BEFORE LIBERTY EXPIRES UNTIL THE SUBTROPICAL RIDGE
RETRACTS BEGINNING NEAR TAU 36. AS THE RIDGE RELEASES PRESSURE ON
THE SYSTEM IT WILL BEGIN A SLOW SOUTHWESTWARD TRACK AND GRADUALLY
INCREASE SPEED. THE TRACK WILL TAKE THE SYSTEM TO THE EAST OF
EUROPA ISLAND BUT CLOSE ENOUGH TO INFLICT PENTY OF DAMAGE.  THE
CORE STRENGTH DURING PASSAGE WILL BE ABOVE 90 KNOTS AT THAT POINT.
CHENESO WILL PEAK AT ABOUT 100 KTS AS IT ROUNDS THE RIDGE AXIS
NEAR THE 24TH LATITUDE AND TAU 72.  ONCE ROUNDING THE RIDGE IT WILL
TRACK TOWARDS THE MID-LATITUDE WESTERLIES BUT THE SYSTEM WILL NOT
ACCELERATE INTO THE WESTERLIES UNTIL THE LATEST PART OF THE
FORECAST PERIOD AND BEYOND. THE TRANSITION PROCESS WILL BE EXTREMELY
SLOW DUE TO THE POLAR JET BEING WELL SOUTH OF THE CONTINENT. 
MID TO HIGH LEVEL MOISTURE FIELDS INDICATE THE CORE WILL NOT BEGIN 
ERODING UNTIL 291800Z, WHEN THE SYSTEM APPROACHES THE 30TH LATITUDE. 
AT THAT POINT, THE SYSTEM WILL BE TRACKING THROUGH 26 DEGREE 
AND BELOW WATERS AND BE UNDERGOING SUBTROPICAL TRANSITION.

MODEL DISCUSSION: TRACK GUIDANCE HAS DONE NOTHING BUT TIGHTEN UP
WITH EACH SUCCESSIVE RUN GIVING MUCH MORE CONFIDENCE TO A TRACK
JUST EAST OF EUROPA ISLAND. INTENSITY GUIDANCE HAS BEEN WIDELY
SPREAD. SOME RAPID INTENSITY GUIDANCE IS TRIGGERING, BUT NONE ARE
OVER 50 PERCENT. THE JTWC FORECAST IS ABOVE THE INTENSITY
CONSENSUS BUT DUE TO THE SLOW MOVEMENT OF THE SYSTEM AND ITS
ASSOCIATED UPWELLING THE PEAK INTENSITY FORECAST IS BASED ON THE
MAXIMUM OUTFLOW EFFECT AS THE SYSTEM ROUNDS THE RIDGE NEAR THE 24TH
LATITUDE. WINDFIELDS ARE EXPANDED ONLY SLOWLY AS THICKNESS PROGS DO
NOT INDICATE ANY PRONOUNCED STRETCHING UNTIL BEYOND THE END OF THE
FORECAST PERIOD. 

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