WDXS31 PGTW 171500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 14S (DUDZAI) WARNING NR 
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.0S 67.4E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 586 NM EAST OF PORT LOUIS, MAURITIUS
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 14S (DUDZAI) AS A STRUGGLING CYCLONE WITH FLARING BUT
SHORT-LIVED CONVECTION LOCATED JUST SOUTH OF THE ASSESSED LOW-LEVEL
CIRCULATION CENTER (LLCC). AN EVIDENT REGION OF VERY DRY AIR HAS
BEEN OBSERVED OVER THE LAST FEW HOURS, WRAPPING CYCLONICALLY AROUND
THE SYSTEMS NORTHERN SEMICIRCLE FROM THE WEST. THE LLCC HAS
REMAINED PARTIALLY OBSCURED SINCE THE PREVIOUS WARNING, HOWEVER,
LOW-LEVEL CUMULIFORM LINES CAN BE SEEN WRAPPING INTO THE CENTER
JUST BENEATH THE CONVECTIVE STRUCTURES CIRRUS CANOPY. ALOFT,
POLEWARD OUTFLOW HAS PERSISTED, ALTHOUGH THE ASSOCIATED SOUTHWARD
CHANNEL HAS BECOME LESS PRONOUCED ON ANIMATED WATER VAPOR IMAGERY,
ALLOWING FOR THE OBSERVED RAPID WEAKENING PHASE. THE ENVIRONMENT
HAS CONTINUED AS MARGINALLY UNFAVORABLE, WITH LARGE SWATHS OF
PRESENT AND PERSISTING DRY AIR, MODERATE VERTICAL WIND SHEAR (VWS)
NEARING 20 KTS, AND SEA SURFACE TEMPERATURES (SST)AND SEA SURFACE 
TEMPERATURES (SST) DIPPING TO 25 C. THE INITIAL POSITION HAS BEEN 
PLACED WITH MEDIUM CONFIDENCE BASED ON ANIMATED EIR IMAGERY. THE 
INITIAL INTENSITY HAS BEEN ASSESSED WITH MEDIUM CONFIDENCE BASED ON 
SUBJECTIVE AGENCY INTENSITY ESTIMATES AND CIMSS OBJECTIVE INTENSITY 
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) POSITIONED TO
THE SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   DEMS: T3.5 - 55 KTS
   FMEE: T3.0 - 45 KTS
   FIMP: T3.0 - 45 KTS
   CIMSS SATCON: 56 KTS AT 170853Z
   CIMSS ADT: 59 KTS AT 171200Z
   CIMSS AIDT: 52 KTS AT 171100Z
   CIMSS D-MINT: 46 KTS AT 170853Z
   CIMSS D-PRINT: 43 KTS AT 171200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 14S IS FORECASTED TO TRACK SOUTHWESTWARD
OVER THE NEXT 72 HOURS, ALONG THE NORTHWESTERN AND WESTERN
PERIPHERY OF THE STR CENTERED TO THE SOUTH. FOLLOWING TAU 72 AND
NEAR THE STR AXIS, TC 14S WILL BEGIN A TERMINAL EAST-SOUTHEASTWARD
TRACK UNTIL EXTRATROPICAL TRANSITION BY TAU 120. DURING THE WINDOW
BETWEEN TAU 72 AND TAU 120, AN EASTWARD PROGRESSING LONGWAVE TROUGH
TO THE SOUTH WILL ASSIST IN THE SYSTEMS EXTRATROPICAL TRANSITION
WHILE USHERING THE CYCLONE QUICKLY POLEWARD. REGARDING INTENSITY,
TC 14S WILL SLOWLY WEAKEN OVER THE NEXT 12 HOURS TOWARD 50 KTS, AS
THE SYSTEMS CORE REMAINS RELATIVELY MOIST. FOLLOWING TAU 12, STEADY
INTENSITIES ARE FORECASTED UNTIL TAU 72 WHILE TC DUDZAI FOLLOWS THE
WESTERN PERIPHERY OF THE STR TO THE SOUTH WITH SUPPORTIVE OUTFLOW
ALOFT AND WARM SST (26-27 C). FOLLOWING TAU 72, GRADUAL WEAKENING IS
FORECASTED AS SST RAPIDLY FALL BELOW 26 C, VWS INCREASES ABOVE 15
KTS, AND DRY AIR ERODES THE SYSTEMS VERTICAL STRUCTURE. BETWEEN TAU
72 AND TAU 120, TC 14S IS FORECASTED TO UNDERGO EXTRATROPICAL
TRANSITION DURING THE FORECASTED SOUTHWARD TRACK TOWARD THE
MID-LATITUDE WESTERLIES. BY TAU 96, SURFACE INTENSITIES WILL
CONTINUE TO WEAKEN AS TC DUDZAI TRACKS COMPLETELY BELOW THE
EQUATORWARD EXTENDING LONGWAVE TROUGH. THE SYSTEM IS EXPECTED TO
COMPLETE EXTRATROPICAL TRANSITION BY TAU 120 WHILE INTENSITIES
CONTINUE TO WEAKEN TO 35 KTS AND TC 14S BECOMES COMPLETELY EMBEDDED
WITHIN THE MID-LATITUDE WESTERLIES.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGHOUT THE FORECAST PERIOD, WITH THE EXCEPTION OF
NAVGEM, WHICH TRACKS THE SYSTEM FURTHER WEST DURING THE FORECASTED
RECURVE THROUGH THE STR AXIS AT TAU 72. THE CROSS-TRACK SPREAD AT TAU 
72 IS JUST 81 NM, INCREASING TO 318 NM BY TAU 120 THROUGH 
EXTRATROPICAL TRANSITION. THE ALONG-TRACK SPREAD DIVERGES QUICKLY 
AFTER TAU 72 DURING THE FORECASTED INTERACTION WITH THE MID-LATITUDE 
WESTERLIES, INCREASING TO 618 NM BY TAU 120. THE JTWC TRACK FORECAST 
IS ALIGNED CLOSELY TO THE MULTI-MODEL CONSENSUS THROUGH THE FORECAST 
PERIOD, LENDING MEDIUM CONFIDENCE TO THE FORECAST TRACK. REGARDING 
INTENSITY, ALL JTWC INTENSITY CONSENSUS MEMBERS ILLUSTRATE A 
RELATIVELY TIGHT ENVELOPE OF STEADY INTENSITIES THROUGH THE NEXT 72 
HOURS, WITH GRADUAL WEAKENING THEREAFTER, LENDING MEDIUM CONFIDENCE TO 
THE JTWC INTENSITY FORECAST.

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