WDXS31 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 08S (CHENESO) WARNING 
NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.6S 41.7E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 87 NM EAST-SOUTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
SIGNIFICANTLY WEAKER TC 08S, BUT MSI AS OF 1300Z INDICATES A
POSSIBLE STRENGTHENING, WITH DEEP CONVECTION WITH COLD CLOUD TOPS
DOWN TO NEAR -80C ARE FIRING IN ACROSS THE SOUTHWESTERN QUADRANT,
WHILE SLIGHTLY LESS VIGOROUS CONVECTION IS DEVELOPING IN THE
NORTHERN PORTIONS OF THE SYSTEM. A 271112Z GMI 37GHZ MICROWAVE
IMAGE SHOWS THAT A WELL-DEFINED LOW-LEVEL EYE HAS REDEVELOPED,
THOUGH THE UPPER-LEVEL EYE IS MUCH MORE RAGGED AS DEPICTED IN THE
89GHZ BAND. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE
USING THE LOW-LEVEL MICROWAVE EYE IN THE GMI IMAGE. THE INITIAL
INTENSITY IS ASSESSED WITH LOW CONFIDENCE, AS THERE CONTINUES TO BE
A VERY WIDE SPREAD IN SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES,
RANGING BETWEEN A LOW OF 32 KNOTS (DMN) AND A HIGH-END CURRENT
INTENSITY ESTIMATE OF T4.0 (65 KNOTS) FROM KNES. THE 50 KNOT
INITIAL INTENSITY IS PLACED ROUGHLY AT THE AVERAGE OF THE AVAILABLE
DATA AND CLOSE THE SATCON ESTIMATE. THE SYSTEM HAS NOW VERY CLEARLY
SET A SOUTHWARD TRACK ALONG THE WEST-SOUTHWEST SIDE OF THE
NEAR-EQUATORIAL RIDGE (NER) CENTERED FAR TO THE NORTHEAST. THE
ENVIRONMENT IS GENERALLY FAVORABLE, CHARACTERIZED BY LOW (5-10
KNOTS) VWS AND STRONG POLEWARD OUTFLOW. THE SYSTEM IS NOW MOVING
INTO AN AREA OF RELATIVELY HIGHER OHC AND WARMER SSTS AS IT MOVES
SOUTH AWAY FROM THE UPWELLING-INDUCED COOL POOL.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WEST-SOUTHWEST PERIPHERY OF A
DEEP-LAYER NEAR EQUATORIAL RIDGE (NER) CENTERED TOO FAR TO THE
NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T4.0 - 65 KTS
   DEMS: T3.0 - 45 KTS
   FMEE: T3.5 - 55 KTS
   CIMSS SATCON: 48 KTS AT 271111Z
   CIMSS ADT: 37 KTS AT 271200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: LOW
   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 08S (CHENESO) HAS NOW BECOME FIRMLY
ENSCONCED ON A GENERALLY SOUTHWARD TRACK, PICKING UP SPEED ALONG A
TIGHTENING GRADIENT ON THE WESTERN SIDE OF THE NER TO THE
NORTHEAST. THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH THE
FIRST 12 HOURS OR SO OF THE FORECAST. BY TAU 24 HOWEVER, THE SYSTEM
WILL TAKE ON A MORE SOUTHEASTWARD TRAJECTORY AHEAD OF A STRONG
MID-LATITUDE TROUGH APPROACHING FROM THE WEST, STEADILY
ACCELERATING THROUGH THE REMAINDER OF THE FORECAST PERIOD. NOW THAT
THE SYSTEM IS PICKING UP THE PACE TOWARDS THE SOUTH, IT IS MOVING
INTO AN AREA OF WARMER, HIGHER OHC WATERS, CURRENTLY MOVING OVER A
POCKET OF OHC VALUES UP TO AROUND 40 KILOJOULES PER SQUARE
CENTIMETER. THIS IS PROVIDING A GOOD SOURCE OF ENERGY FOR THE
RECENT BURST OF CONVECTIVE ACTIVITY. THE SYSTEM SHOULD REMAIN OVER
THIS WARM POOL FOR ABOUT 12 HOURS, WHICH SHOULD ALLOW FOR THE
CONVECTION TO CONTINUE TO INTENSIFY AND ORGANIZE ABOUT THE CORE AND
THE SYSTEM WILL QUICKLY INTENSIFY UP TO 65 KNOTS BY TAU 12. AFTER
TAU 24, THE SYSTEM WILL START TO FEEL THE EFFECTS OF THE
APPROACHING TROUGH, AS NORTHWESTERLY MID-LEVEL WINDS INCREASE
SHARPLY AND BEGIN TO INTRODUCE DRY AIR ABOVE 600MB, WHICH BEGINS TO
ERODE THE NORTHERN SIDE OF THE CIRCULATION. MID-LEVEL SHEAR AND DRY
AIR ENTRAINMENT STEADILY INCREASE AFTER TAU 36 AS THE TROUGH BEGINS
TO MAKE ITS PRESENCE KNOWN IN EARNEST. AS IT RACES OFF TO THE
SOUTHEAST, TC 08S WILL LIKELY BE DECAPITATED AROUND TAU 48 AS IT
MOVES UNDER A 200MB JET STREAK AND SHEAR VALUES EXCEED 40 KNOTS.
THE SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION (ETT) AT THIS POINT
AND IS EXPECTED TO COMPLETE ETT BY TAU 72 OR SHORTLY THEREAFTER. 

MODEL DISCUSSION: ALL AVAILABLE DETERMINISTIC TRACK GUIDANCE AGREES
ON THE TRACK SCENARIO, WITH MODEST CROSS AND ALONG-TRACK SPREAD
DEVELOPING AFTER TAU 48. THE JTWC FORECAST LIES CLOSE TO THE
MULTI-MODEL CONSENSUS BUT CONTINUES TO BE SLIGHTLY FASTER THAN THE
MEAN AFTER TAU 36. INTENSITY GUIDANCE IS BY AND LARGE IN GOOD
AGREEMENT. THE HWRF IS THE MOST BULLISH OF THE GUIDANCE, PEAKING
THE SYSTEM AT 65 KNOTS, WHILE THE COAMPS-TC (GFS) TRAILS FIVE KNOTS
LOWER WHILE THE REMAINDER OF THE GUIDANCE IS PEAKING AT 55 KNOTS.
THE BULK OF THE GUIDANCE CONVERGES ABOUT THE MEAN BY TAU 36, THOUGH
THE HWRF WEAKENS THE SYSTEM AT A MUCH FASTER RATE AND LIES ABOUT 10
KNOTS LOWER THAN THE CONSENSUS AFTER TAU 36. THE JTWC FORECAST
TRACKS THE HWRF THROUGH TAU 24, THEN LIES SLIGHTLY ABOVE THE
CONSENSUS THEREAFTER. 

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