WDXS31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (DUDZAI) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.2S 77.6E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 676 NM SOUTH-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FAIRLY
SYMMETRICAL CENTRAL DENSE OVERCAST (CDO) FEATURE FULLY OBSCURING
THE LOW-LEVEL CIRCULATION CENTER OF TROPICAL CYCLONE (TC) 14S
(DUDZAI). THE SYSTEM BECAME QUASI-STATIONARY SHORTLY AFTER IT MADE
A WESTWARD TURN. INCREASED DRY AIR ENTRAINMENT ORIGINATING FROM THE
NORTH, AS WELL AS MODERATE (15-20 KTS) VERTICAL WIND SHEAR (VWS)
CONTRIBUTED TO SIGNIFICANT WEAKENING OVER THE LAST 12 HOURS,
RESULTING IN CURRENTLY ASSESSED INTENSITY OF 80 KTS. OFFSETTING THE
MAINLY UNFAVORABLE ENVIRONMENTAL CONDITIONS IS PERSISTING MODERATE
POLEWARD OUTFLOW. ADDITIONAL ANALYSIS OF THE ENVIRONMENT REVEALS
UPWELLING OF THE COOLER SUB-SURFACE WATER OCCURRING DUE TO SLOW
TRANSLATIONAL SPEED OF THE SYSTEM. THE INITIAL POSITION IS ASSESSED
WITH HIGH CONFIDENCE BASED ON A 131732Z GPM GMI PASS SHOWING A
CLEAR MICROWAVE EYE FEATURE. THE INITIAL INTENSITY IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE COMBINATION OF OBJECTIVE AND DVORAK
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: BUILDING SUBTROPICAL RIDGE TO THE
SOUTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   DEMS: T5.0 - 90 KTS
   FIMP: T5.0 - 90 KTS
   CIMSS ADT: 74 KTS AT 131500Z
   CIMSS AIDT: 73 KTS AT 131700Z
   CIMSS D-MINT: 80 KTS AT 131732Z
   CIMSS D-PRINT: 76 KTS AT 131745Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE NORTH

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   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 DUDZAI IS FORECAST TO VERY SLOWLY BEGIN TO
ACCELERATE WESTWARD, OWING TO A WEAK STEERING REGIME CHARACTERIZED
BY COMPETING INFLUENCES WITHIN THE AREA OF INTEREST. OVER THE NEXT
24 TO 36 HOURS, THE SYSTEM IS EXPECTED TO CONTINUE WEAKENING DUE TO
UNFAVORABLE ENVIRONMENT CHARACTERIZED ABOVE. AS THE SUBTROPICAL
RIDGE CURRENTLY CENTERED TO THE SOUTHWEST BUILDS AND REPOSITIONS
SOUTH OF THE VORTEX, TC 14S WILL BEGIN TO GAIN SPEED OVER WATER.
CONSEQUENTLY, AFTER TAU 48 TC DUDZAI WILL CIRCUMNAVIGATE THE
NORTHWESTERN PERIPHERY OF THE STR AND TRANSLATE SOUTHWESTWARD
THROUGH THE REMAINDER OF THE FORECAST PERIOD. REGARDING INTENSITY
DURING THAT STAGE, AN ENHANCED POLEWARD OUTFLOW CHANNEL IS EXPECTED
TO ESTABLISH SOUTH OF THE SYSTEM BEFORE TAU 48, POTENTIALLY
FACILITATING SLIGHT RE-INTENSIFICATION. HOWEVER, THE POSITIVE
IMPACTS OF THIS UPPER-LEVEL DIVERGENCE WILL BE MITIGATED BY
SIGNIFICANT DRY AIR INTRUSION EXPECTED AFTER TAU 72, FURTHER
ENHANCED BY COOLER SEA SURFACE TEMPERATURES AND INCREASING VERTICAL
WIND SHEAR.

MODEL DISCUSSION: DETERMINISTIC NUMERICAL WEATHER PREDICTION TRACK
GUIDANCE EXHIBITS MODERATE CONSENSUS REGARDING THE PROJECTED
SYNOPTIC STEERING PATTERN. TRACK FORECAST CONFIDENCE IS MEDIUM,
STEMMING FROM UNCERTAINTY IN THE TEMPORAL EXECUTION OF THE
ACCELERATION EXPECTED OVER THE NEXT 12 HOURS. CROSS-TRACK SPREAD IS
ESTIMATED TO BE BETWEEN 40 AND 50 NM WITHIN THE INITIAL 12 HOURS,
MAINLY DUE TO A MORE SOUTHERN GUIDANCE OFFERED BY GALWEM AND UKMET
MODELS. THE TRACK GUIDANCE ENVELOPE EXPANDS UPWARDS OF 200 NM
TOWARDS THE END OF THE FORECAST PERIOD INDICATING UNCERTAINTY
ASSOCIATED WITH THE IMPACT OF THE STR ON THE TRACK OF THE SYSTEM.
THE OFFICIAL JTWC TRACK FORECAST IS POSITIONED ALONG THE NORTHERN
EXTENT OF THE MULTI-MODEL CONSENSUS, MAINTAINING AN APPROXIMATE 25
NM DISTANCE FROM THE ENVELOPE MEAN. REGARDING INTENSITY GUIDANCE,
MODELS ARE IN HIGH AGREEMENT DEPICTING A PRECIPITOUS WEAKENING
TREND THROUGH TAU 24. BEYOND TAU 24, GUIDANCE DIVERGENCE INCREASES
SIGNIFICANTLY. HAFS AND HWRF PREDICT ROBUST RE-INTENSIFICATION TO
100-125 KTS, WHEREAS GFS AND COAMPS-TC REPRESENT THE MIDDLE OF THE
INTENSITY ENVELOPE, DEPICTING INTENSITY STABILIZATION OR MINOR
FLUCTUATIONS IN MAXIMUM SUSTAINED WINDS AT LEAST THROUGH TAU 72.
ACCORDINGLY, JTWC OFFICIAL INTENSITY FORECAST CONFIDENCE IS MEDIUM,
LAID CLOSE TO THE CONSENSUS MEAN, BUT LEANING TOWARD HAFS AND HWRF
SOLUTIONS BASED ON THE ANALYSIS OF THE UPPER-LEVEL ENVIRONMENT.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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