WDXS31 PGTW 290300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 08S (CHENESO) WARNING 
NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.7S 43.9E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 386 NM SOUTH-SOUTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 17 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
OVERALL ERODING SYSTEM WITH INDICATIONS OF DRY AIR BEING INTRODUCED
INTO THE LOW LEVEL CIRCULATION CENTER (LLCC). TC CHENESO HAS LOST
ALL OF ITS INNER CONVECTIVE ACTIVITY OVER THE PAST 12 HOURS AND IS
HEADING ITS WAY OUT THE DOOR AS IT PICKS UP TRACK SPEED (17 KTS)
BEARING SOUTHEAST. UNFORTUNATELY, THE 281847Z ASCAT-B AND THE
281939Z ASCAT-C PASSES WERE MISSES AND ONLY CAPTURED THE OUTER
PORTION OF THE WESTERN SEMI-CIRCLE. THE SYSTEM IS CURRENTLY IN A
MARGINALLY FAVORABLE ENVIRONMENT WITH ROBUST POLEWARD OUTFLOW
ALOFT, LOW (10-15 KTS) VERTICAL WIND SHEAR, AND BORDERLINE WARM
(26 C) SEA SURFACE TEMPERATURES. HOWEVER, IN JUST A MATTER OF
HOURS, TC CHENESO WILL BE IN UNFAVORABLE ENVIRONMENTAL CONDITIONS
FOR ANY FUTURE TROPICAL DEVELOPMENT. THE INITIAL POSITION IS PLACED
WITH MEDIUM CONFIDENCE BASED OF THE AFOREMENTIONED SATELLITE
IMAGERY, AS WELL AS MULTIPLE AGENCY FIXES. THE INITIAL INTENSITY OF
60 KNOTS IS SET WITH MEDIUM CONFIDENCE SET HIGHER THAN MULTIPLE
AGENCY DVORAK ESTIMATES, AND SLIGHTLY LOWER THAN ADT OF 63 KTS, AND
THE SATCON VALUE OF 61 KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   FMEE: T4.5 - 77 KTS
   CIMSS SATCON: 61 KTS AT 281632Z
   CIMSS ADT: 63 KTS AT 282100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC CHENESO HAS COMPLETED ITS ROUNDING OF THE
SUBTROPICAL RIDGE AXIS AND IS NOW SPEEDING ITS WAY TO THE SOUTHEAST
WHILE FALLING UNDER THE INFLUENCE OF THE APPROACHING MAJOR
SHORTWAVE TROUGH TO THE SOUTHWEST. IN APPROXIMATELY 12 HOURS, TC
CHENESO WILL BE IN A MORE HOSTILE ENVIRONMENT CHARACTERIZED BY
STRONG (35-40 KTS) VWS AND COOLER (24-25 C) SSTS. IN ADDITION, BY
TAU 12, TC 08S WILL BEGIN ITS EXTRATROPICAL TRANSITION. BY TAU 24,
DRY AIR WILL OVERCOME THE NORTHWEST SEMICIRCLE AND FRONTS WILL
BEGIN TO BECOME APPARENT AS INDICATED BY THE 281800Z GFS RUN OF THE
1000-500MB THICKNESS FORECAST. BY TAU 36, TC CHENESO WILL BECOME
FULLY EXTRATROPICAL.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN VERY TIGHT
AGREEMENT WITH A 32 NM SPREAD AT TAU 12, GRADUALLY INCREASING TO A
95 NM SPREAD AT TAU 36. THE JTWC TRACK IS SET WITH HIGH CONFIDENCE
BASED OFF ALL AGREEABLE DATA. THE JTWC INTENSITY IS SET WITH MEDIUM
CONFIDENCE FAVORING THE MODEL CONSENSUS WHICH INDICATES A DECREASE
IN INTENSITY TO TAU 24, THEN MAINTAINING THE INTENSITY OF 50 KTS
WHILE IT TRANSITIONS TO A EXTRATROPICAL SYSTEM.

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