WDXS31 PGTW 150900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (DUDZAI) WARNING NR 
010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.1S 74.3E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 609 NM SOUTH OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 14S (DUDZAI) WITH A PARTIALLY FILLED EYE AND A HIGHLY
SYMMETRICAL CENTRAL DENSE OVERCAST (CDO) SURROUNDING THE EYEWALL.
THE SYSTEM HAS BEEN ANALYZED TO HAVE COMPLETED ANOTHER BOUT OF
RAPID INTENSIFICATION (RI) FROM 65 KTS 24 HOURS AGO TO 95 KTS NOW.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
EYE IN ANIMATED MSI. THE INITIAL INTENSITY OF 95 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED PRIMARILY ON THE AGENCY DVORAK FIXES
BELOW. CIMSS OBJECTIVE INTENSITY ESTIMATES ARE FAR TOO LOW DUE TO
THE EYE SCENE TYPE NOT BEING USED. ENVIRONMENTAL ANALYSIS
INDICATES THAT 14S IS IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY
STRONG POLEWARD OUTFLOW ALOFT, LOW (10-15 KTS) VERTICAL WIND SHEAR,
AND WARM (27-28 C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: THE NORTHEASTERN PERIPHERY OF A
SUBTROPICAL RIDGE (STR) CENTERED TO THE SOUTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   DEMS: T5.5 - 102 KTS
   FMEE: T5.0 - 90 KTS
   FIMP: T5.0 - 90 KTS
   CIMSS ADT: 57 KTS AT 150600Z
   CIMSS AIDT: 66 KTS AT 150600Z
   CIMSS D-PRINT: 82 KTS AT 150600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE NEAR-TERM INTENSITY IS FORECAST
TO BE HIGHER DUE TO THE RECENT RI. OTHERWISE, NO SIGNIFICANT
CHANGES TO THE FORECAST.

FORECAST DISCUSSION: TC 14S IS FORECAST TO TRACK WESTWARD, ALONG
THE NORTHERN PERIPHERY OF THE STR THROUGH TAU 36. NEAR TAU 36, THE
STR IS FORECAST TO PROPAGATE EASTWARD, AND 14S WILL BEGIN TO ROUND
THE NORTHWESTERN EXTENT OF IT. THIS WILL INITIATE A SOUTHWESTWARD
TRACK, WHICH WILL PERSIST THROUGH TAU 120. REGARDING INTENSITY, 14S
IS FORECAST TO CONTINUE INTENSIFYING THROUGH TAU 12 DUE TO THE
CONTINUED FAVORABLE ENVIRONMENT. HOWEVER, AFTER TAU 12, DRY AIR
ENTRAINMENT FROM THE NORTH IS EXPECTED TO BEGIN INCREASING. IN
ADDITION TO THE DRY AIR, THE POLEWARD OUTFLOW CHANNEL IS EXPECTED TO
WEAKEN. THESE TWO FACTORS WILL CAUSE 14S TO STEADILY WEAKEN THROUGH
TAU 48. AFTER TAU 48, NORTHWESTERLY SHEAR IS EXPECTED TO INCREASE,
FURTHER AIDING IN WEAKENING THE SYSTEM THROUGH THE REMAINDER OF THE
FORECAST PERIOD. NEAR TAU 120, 14S WILL ENTER BORDERLINE SEA
SURFACE TEMPERATURES OF 25-26 C AS THE SYSTEM CONTINUES TO GAIN
LATITUDE.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH THE EXCEPTION OF
NAVGEM, WHICH TRACKS THE VORTEX MUCH FURTHER SOUTH THAN THE
REMAINDER OF GUIDANCE. DISCOUNTING NAVGEM, THERE IS A CROSS-TRACK
SPREAD OF AROUND 100 NM AT TAU 72. ALONG-TRACK SPREAD IS A BIT
LARGER WITH ECMWF BEING THE SLOWEST MODEL WHILE GFS IS THE FASTEST.
ALONG-TRACK SPREAD AT TAU 72 IS AROUND 220 NM. AFTER TAU 72,
CROSS-TRACK SPREAD REMAINS SMALL, BUT ALONG-TRACK SPREAD INCREASES
TO AROUND 250 NM. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE
MULTI-MODEL CONSENSUS WITH MEDIUM CONFIDENCE. INTENSITY GUIDANCE
AGREES ON WEAKENING FROM TAU 12 ONWARD WITH NO SIGNIFICANT
OUTLIERS. THE JTWC INTENSITY FORECAST IS ALSO PLACED NEAR THE
CONSENSUS WITH MEDIUM CONFIDENCE. 

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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