WDXS31 PGTW 211500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 21S (CHARLOTTE) 
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.0S 110.6E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 427 NM NORTH-NORTHWEST OF LEARMONTH,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TC 21S HAS RECONSOLIDATED AFTER A BRIEF PERIOD OF DIURNAL WEAKENING.
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN 
IMPROVED CENTRAL DENSE OVERCAST STRUCTURE WITH STRONG RADIAL AND 
POLEWARD OUTFLOW. A 211251Z GMI 89 GHZ COLOR COMPOSITE MICROWAVE 
IMAGE DEPICTS TIGHTLY CURVED BANDING AND A SMALL 5NM DIAMETER 
MICROWAVE EYE FEATURE. A 211021Z SMOS WINDSPEED IMAGE DEPICTS A 
REGION OF 55-64 KNOT WINDS (CONVERTED TO ONE MINUTE AVERAGE) CONFINED 
IN THE SOUTHEASTERN SECTOR OF THE SYSTEM. THE INITIAL POSITION IS 
PLACED WITH HIGH CONFIDENCE BASED ON THE 211251Z MICROWAVE IMAGE. THE
INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED
ON A COMBINATION OF THE 211021Z SMOS WINDSPEED DATA AND AGENCY
DVORAK INTENSITY ESTIMATES RANGING FROM 55-65 KNOTS.

INITIAL WIND RADII BASIS: 211021Z SMOS WINDSPEED IMAGE

CURRENT STEERING MECHANISM: DEEP LAYERED SUBTROPICAL RIDGE (STR) TO
THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   APRF: T4.0 - 65 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: INCREASING POLEWARD OUTFLOW INTO THE SUBTROPICAL
WESTERLIES 

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 21S (CHARLOTTE) WILL CONTINUE TRACKING
UNDER THE STEERING INFLUENCE OF THE STR TO THE SOUTHEAST IN A
HIGHLY FAVORABLE ENVIRONMENT. TC 21S HAS DEVELOPED RAPIDLY INTO A
COMPACT, WELL-DEFINED SYSTEM WITH A HIGH LIKELIHOOD OF RAPID
INTENSIFICATION OVER THE NEXT 12 HOURS. VIGOROUS RADIAL AND
POLEWARD OUTFLOW COUPLED WITH WARM SEA SURFACE TEMPERATURES AND LOW
VERTICAL WIND SHEAR WILL ALLOW TC 21S TO REACH A PEAK INTENSITY OF
85 KNOTS WITH A POSSIBILITY OF A HIGHER PEAK BEFORE TAU 12. BETWEEN
TAU 12 AND TAU 24 THE STR TO THE SOUTHEAST WILL BREAK DOWN DUE TO
AN APPROACHING UPPER-LEVEL SUBTROPICAL TROUGH. AS THIS HAPPENS,
OUTFLOW WILL BEGIN TO WEAKEN AND DRY AIR ENTRAINMENT WILL COMMENCE
RESULTING IN A SHARP WEAKENING TREND. NEAR TAU 48, TC 21S WILL
BEGIN TO INTERACT WITH THE SUBTROPICAL WESTERLIES, TURN
SOUTH-SOUTHWESTWARD THROUGH TAU 72 AND INCREASE IN SPEED AND
CONTINUE WEAKENING. BY TAU 96, THE SYSTEM WILL TRACK GENERALLY
SOUTHWARD IN AN INCREASINGLY BAROCLINIC ENVIRONMENT WITH HIGH VWS
(30-35 KTS) AND COOLER SST (25-26C). TC 21S WILL CONTINUE WEAKENING
AND EVENTUALLY BECOME FULLY EMBEDDED IN THE TROUGH AND COMPLETE 
SUBTROPICAL TRANSITION BY TAU 120.

MODEL DISCUSSION: WITH THE EXCEPTION OF AFUM, NUMERICAL MODEL
GUIDANCE IS IN FAIR AGREEMENT WITH A 100NM SPREAD AT TAU 72,
SUPPORTING THE JTWC FORECAST TRACK WITH MEDIUM CONFIDENCE. THE JTWC
FORECAST TRACK IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS
(CONW). THE JTWC INTENSITY FORECAST IS PLACED ABOVE THE BULK OF THE
INTENSITY GUIDANCE, WHICH WEAKENS THE SYSTEM QUICKER DUE TO DRY AIR
ENTRAINMENT OVER THE NEXT 12 HOURS. HWRF PRESENTS A MORE REALISTIC
SOLUTION AND COCOONS THE COMPACT CORE FROM DRY AIR ENTRAINMENT
UNTIL AFTER TAU 24 THUS THE JTWC INTENSITY FORECAST IS ALIGNED
CLOSER TO HWRF.

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