WDXS31 PGTW 122100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (DUDZAI) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.0S 78.0E
   INITIAL INTENSITY: 115 KTS
   GEOGRAPHIC REFERENCE: 676 NM SOUTH-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 14S (DUDZAI) SLOWING ITS SOUTH-SOUTHEASTWARD MOVEMENT
AS IT APPROACHES THE NORTHWESTERN PERIPHERY OF A STR CENTERED TO
THE SOUTHEAST. THE SYSTEM HAS LIKELY REACHED ITS PEAK INTENSITY OF
120-125 KTS WITHIN THE LAST 6-12 HOURS. DRY AIR ENTRAINMENT CAN BE 
SEENSTARTING TO WRAP INTO THE CORE OF THE VORTEX PRIMARILY FROM THE
NORTH. SLOW TRANSLATION SPEED IS INCREASING THE IMPACTS OF
UPWELLING AND SLIGHTLY COOLING SEA SURFACE TEMPERATURES (SST).
ADDITIONAL ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE CONDITIONS, 
INCLUDING LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS) AND GOOD POLEWARD 
OUTFLOW. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE, BASED ON 
THE EYE FEATURE, WHICH HAS BEEN SLOWLY FILLING, WHILE THE TEMPERATURES 
COOLED RAPIDLY, FROM AROUND 7 C AT 15Z, DOWN TO -38 C AT 18Z. THE 
INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON THE 
121320Z RCM-3 SAR DATA IN CONJUNCTION WITH THE OBJECTIVE AND AGENCY 
DVORAK ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: 121320Z RCM-3 SAR DATA

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   DEMS: T6.0 - 115 KTS
   FMEE: T6.5 - 127 KTS
   FIMP: T6.5 - 127 KTS
   CIMSS SATCON: 118 KTS AT 121419Z
   CIMSS ADT: 119 KTS AT 121800Z
   CIMSS AIDT: 118 KTS AT 121700Z
   CIMSS D-MINT: 117 KTS AT 121812Z
   CIMSS D-PRINT: 112 KTS AT 121800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

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 DUDZAI IS FORECAST TO CONTINUE SLOWING DOWN
SIGNIFICANTLY OVER THE NEXT 12-24 HOURS, AS A RESULT OF A COMPETING
STEERING ENVIRONMENT DEVELOPING WITHIN THE AREA OF INTEREST. THE
SYSTEM CAN ALREADY BE SEEN STARTING TO TRACK SOUTHWARD. AROUND TAU
12, A DEVELOPING STR CENTERED TO THE SOUTHWEST WILL RESULT IN
PUSHING THE SYSTEM WEST-SOUTHWESTWARD. AFTER THAT, TC 14S IS
EXPECTED TO TRACK WESTWARD UNTIL TAU 72. AROUND THAT TIME, THE
BUILDING STR TO THE SOUTHWEST WILL REPOSITION SOUTHEAST OF THE
STORM. AS A RESULT, TC DUDZAI WILL BEGIN TO ROUND THE NORTHWESTERN
PERIPHERY OF THE STR AND TRACK SOUTHWESTWARD THROUGH THE REMAINDER
OF THE FORECAST PERIOD. IN REGARD TO INTENSITY, TC 14S IS EXPECTED
TO CONTINUE WEAKENING FOR THE NEXT 36-48 HOURS, PRIMARILY DUE TO
IMPACTS OF THE COLD WATER UPWELLING, AND DRY AIR INTRUSION. VERTICAL
WIND SHEAR IS EXPECTED TO REMAIN LOW TO MODERATE THROUGHOUT THE
DURATION OF THE FORECAST, HOWEVER AROUND TAU 72 A ROBUST POLEWARD
OUTFLOW CHANNEL WILL OPEN UP TO THE SOUTH OF THE SYSTEM, ALLOWING
ROOM FOR RE-INTENSIFICATION. POSITIVE IMPACTS OF GREAT OUTFLOW WILL
HOWEVER CONTINUE TO BE LIMITED BY THE INTRODUCTION OF DRY AIR, WHICH 
IS
EXPECTED TO BECOME MORE SIGNIFICANT BETWEEN TAUS 72 AND 96.

MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IS IN OVERALL FAIR
AGREEMENT IN REGARD TO THE TRACK, WITH NEARLY ALL MODELS AGREEING
ON THE GENERAL SYNOPTIC STEERING PATTERN. THE TRACK FORECAST IS
ASSESSED WITH MEDIUM CONFIDENCE, DUE TO UNCERTAINTY ASSOCIATED WITH
THE TIMELINE OF THE COMPLETION OF THE WESTWARD TURN EXPECTED TO
OCCUR WITHIN THE NEXT 6-12 HOURS. MAJOR OUTLIERS ARE CURRENTLY GALWEM, 
WITH THE INITIAL NORTHWESTWARD TRACK PREDICTION, AS WELL AS NAVGEM 
SUGGESTING A FASTER SOUTHWESTWARD TURN ALONG THE NORTHWESTERN 
PERIPHERY OF THE STR. JTWC OFFICIAL TRACK FORECAST IS LAID ON THE 
NORTHERN SIDE AND WITHIN APPROXIMATELY 25 NM OF THE MULTI-MODEL 
CONSENSUS TRACK. IN REGARD TO INTENSITY, MODELS ARE IN GOOD AGREEMENT 
ON A RATHER STEEP WEAKENING TREND FOR THE NEXT 36 HOURS. AFTER THAT, 
THE GUIDANCE IS IN POOR AGREEMENT, WITH HAFS AND HWRF PREDICTING STEEP 
INTENSIFICATION, POTENTIALLY UP TO 110-120 KT, WHILE STATISTICAL-
DYNAMICAL SHIPS GUIDANCE PREDICTS STEADY AND CONTINUOUS WEAKENING. IN 
THE MIDDLE OF THE GUIDANCE ENVELOPE GFS AND COAMPS-TC CAN BE FOUND, 
WITH STEADYING INTENSITY, OR SOME VERY MINOR INCREASE IN MAXIMUM 
WINDS. AS SUCH, THE OFFICIAL JTWC INTENSITY FORECAST IS ASSESSED WITH 
LOW CONFIDENCE AFTER TAU 72, BUT LEANING SLIGHTLY TOWARDS THE GUIDANCE 
FROM HAFS AND HWRF, BASED ON THE ANALYSIS OF THE SYNOPTIC ENVIRONMENT.

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