WDXS31 PGTW 162100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 07S (DIKELEDI) WARNING 
NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 31.8S 48.9E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 740 NM SOUTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 20 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS WARMING
CLOUD TOPS AS DEEP CONVECTION COLLAPSES AND IS DRAWN POLEWARD AND
EASTWARD OF THE OBSCURED LOW-LEVEL CIRCULATION CENTER (LLCC). WATER
VAPOR IMAGERY REVEALS WEAK POLEWARD OUTFLOW AS THE CIRCULATION
BEGINS TO INTERACT WITH MID-LATITUDE WESTERLIES ALOFT. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 161803Z GPM GMI
37GHZ MICROWAVE IMAGE REVEALING A DISTINCT EYE FEATURE ON THE
LOW-LEVELS. THE INITIAL INTENSITY OF 75 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE RAPIDLY DEGRADING STRUCTURE OF THE SYSTEM
COUPLED WITH THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE (STR) TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T5.5 - 102 KTS
   FMEE: T5.0 - 90 KTS
   CIMSS ADT: 94 KTS AT 161800Z
   CIMSS AIDT: 92 KTS AT 161800Z
   CIMSS D-MINT: 75 KTS AT 161830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 20-25 KTS
   SST: 23-24 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE FORECAST TIMELINE HAS BEEN
SHORTENED DUE TO THE QUICKLY DEGRADING NATURE OF TROPICAL CYCLONE
(TC) 07S AS THE SYSTEM PASSES OVER COOL SEA SURFACE TEMPERATURES
AND VERTICAL WIND SHEAR INCREASES.

FORECAST DISCUSSION: TC 07S WILL CURVE EAST-SOUTHEASTWARD ON THE
SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE FOR THE NEXT 24 HOURS.
THE SYSTEM WILL CONTINUE INTO THE BAROCLINIC ZONE, FORCING
EXTRATROPICAL TRANSITION. TC 07S WILL CONTINUE TO WEAKEN AS THE
STRUCTURE OF THE CIRCULATION DEGRADES FOR THE REMAINDER OF THE
FORECAST, DRIVEN PRIMARILY BY BAROCLINIC FORCING AND COOL SEA
SURFACE TEMPERATURES. THE OUTFLOW ENVIRONMENT WILL REMAIN
UNFAVORABLE WITH MIDLATITUDE WESTERLY FLOW ALOFT. VERTICAL WIND
SHEAR WILL INCREASE GRADUALLY OVER THE NEXT 24 HOURS TO 35-40KTS.
EXTRATROPICAL TRANSITION IS FORECAST TO COMPLETE WITHIN 24 HOURS
WHEN THE SYSTEM WILL BE FULLY FRONTAL, BAROCLINIC, AND EMBEDDED
WITHIN THE JET.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT THAT THE SYSTEM WILL CURVE EAST-SOUTHEASTWARD FOR THE
REMAINDER OF THE FORECAST PERIOD UNDER THE STEERING INFLUENCE OF
THE STR TO THE NORTH. THE INTENSITY GUIDANCE IS IN STRONG AGREEMENT
THAT THE INTENSITY WILL DEGRADE FOR THE REMAINDER OF THE FORECAST
AS THE SYSTEM UNDERGOES EXTRATROPICAL TRANSITION.

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