WDXS31 PGTW 201500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 24S (IALY) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 5.8S 43.8E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 275 NM EAST-NORTHEAST OF DAR ES SALAAM,
TANZANIA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTION REDEVELOPING AROUND THE CIRCULATION CENTER, WHICH
PRESENTS AS AN EYE FEATURE IN 201055Z AMSR2 IMAGERY. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE NEAR THE MICROWAVE EYE
EVIDENT IN THE AFOREMENTIONED AMSR2 PASS. ONGOING RECONSOLIDATION
OF THE LOW-LEVEL STRUCTURE AND AN APPARENT JOG FARTHER TO THE WEST
THAN PREVIOUSLY ANTICIPATED IS CONTRIBUTING SOME UNCERTAINTY TO THE
INTIAL POSITION. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON MULTI-AGENCY DVORAK CURRENT INTENSITY
ESTIMATES, A CIMSS AIDT VALUE OF 52 KTS, AND SUPPORTIVE
PRESENTATION IN MICROWAVE SATELLITE IMAGERY. OTHER AUTOMATED
INTENSITY GUIDANCE, INCLUDING THE CIMSS SATELLITE CONSENSUS,
AUTOMATED DVORAK AND DPRINT APPEAR TO BE UNDER-ANALYZING THE
INTENSITY, PARTICULARLY IN LIGHT OF THE MICROWAVE SATELLITE
PRESENTATION, AND POSSIBLY DUE TO THE COMPACTNESS OF THE SYSTEM.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE POSITIONED TO THE
WEST AND ASSOCIATED EXTENSION TO THE SOUTHWEST OF THE SYSTEM

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   FMEE: T3.5 - 55 KTS
   CIMSS SATCON: 42 KTS AT 201018Z
   CIMSS ADT: 33 KTS AT 200900Z
   CIMSS DPRINT: 42 KTS AT 201200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: FORECAST INTENSITIES HAVE INCREASED
SLIGHTLY FROM THE PREVIOUS WARNING BASED ON RECENT TRENDS.

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 24S IS DISPLAYING
STRUCTURAL IMPROVEMENTS INCLUDING THE REAPPEARANCE OF A MICROWAVE
EYE WITH SUPPORT FROM GENERALLY FAVORABLE NEAR-TERM ENVIRONMENTAL
CONDITIONS. ADDITIONAL IMPROVEMENT AND PERHAPS SOME INTENSIFICATION
OVER THE NEXT SIX HOURS SEEMS LIKELY AT THIS POINT. HOWEVER, ANY
INTENSIFICATION TREND WILL LIKELY BE SHORT LIVED. THE SYSTEM WILL
FACE INCREASINGLY UNFAVORABLE CONDITIONS AS THE NEAR-EQUATORIAL
RIDGE TO THE WEST EXERTS AN INCREASING INFLUENCE ON STORM MOTION
AND CARRIES THE SYSTEM NORTHWARD OVER THE NEXT DAY AND A HALF. TC
24S IS EXPECTED TO CONTEND WITH INCREASING EASTERLY VERTICAL WIND
SHEAR, REDUCED POLEWARD OUTFLOW ALOFT, AND ENTRAINMENT OF DRIER
CONTINENTAL AIR BY TAU 12. THESE FACTORS ARE EXPECTED TO DRIVE
WEAKENING UNTIL THE SYSTEM DISSIPATES BELOW THE WARNING THRESHOLD
INTENSITY OF 35 KNOTS BY TAU 36.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
REGARDING OVERALL SYNOPTIC CONDITIONS AND NORTHWARD ORIENTATION OF
THE FORECAST TRACK. HOWEVER, THERE IS NOTABLE SPREAD IN TRACK
SPEEDS, WHICH REFLECTS MODEL UNCERTAINTY REGARDING THE SPEED WITH 
WHICH THE STEERING RIDGE TO THE WEST WILL BUILD IN TO PUSH THE
SYSTEM NORTHWARD. THE CURRENT FORECAST LIES CLOSE TO THE MULTI-MODEL
CONSENSUS, A BIT SLOWER THAN THE GFS-BASED GUIDANCE, NEAR UK MODEL
GUIDANCE, AND A BIT FASTER THAN THE NAVGEM AND ECMWF ENSEMBLE MEAN
SOLUTIONS. A SLOWER NORTHWARD TRACK INTO LESS FAVORABLE
ENVIRONMENTAL CONDITIONS COULD MEAN MORE TIME THE CURRENT FAVORABLE
ENVIRONMENT, DELAYING THE EXPECTED WEAKENING TREND. MESOSCALE MODEL
GUIDANCE CONTINUES TO SHOW NEAR-TERM STEADY INTENSITY FOLLOWED BY
SHARP MEDIUM-TERM WEAKENING TRENDS WHILE SHIPS HOLDS THE SYSTEM
STEADY FAR PAST THE EXPECTED DISSIPATION POINT. HOWEVER, THE
MAJORITY OF MODEL TRACK AND INTENSITY SOLUTIONS ARE CONSISTENT WITH
THE PROJECTED NORTHWARD MOTION AND WEAKENING SCENARIO, WITH SPEED
AND TIMING AS THE REMAINING SOURCES OF MEDIUM-TERM UNCERTAINTY.

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