WDXS31 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 07S (DIKELEDI) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.7S 51.6E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 441 NM NORTH-NORTHEAST OF ANTANANARIVO,
MADAGASCAR
   MOVEMENT PAST 6 HOURS: WESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 31 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A DIMPLE-LIKE 
FEATURE EMBEDDED WITHIN A DEEP CONVECTIVE MASS OBSCURING THE CENTER 
OF THE TROPICAL CYCLONE (TC) 07S. THE DIMPLING FEATURE INDICATING A 
FORMATIVE EYE HIGHLIGHTS THE INTENSIFICATION THAT HAS OCCURRED OVER 
THE LAST 12 HOURS. AN 110213Z RCM-3 SYNTHETIC APERTURE RADAR (SAR) 
PRODUCT REVEALS WIND SPEEDS IN THE SOUTHERN AND SOUTHWESTERN 
PERIPHERY BETWEEN 75-77KTS. THE INITIAL POSITION IS PLACED WITH HIGH 
CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED MSI. THE INITIAL 
INTENSITY OF 75 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE 
AFOREMENTIONED SCATTEROMETRY.

INITIAL WIND RADII BASIS: SAR DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T4.0 - 65 KTS
   FMEE: T4.5 - 77 KTS
   CIMSS SATCON: 65 KTS AT 110530Z
   CIMSS ADT: 55 KTS AT 110300Z
   CIMSS AIDT: 67 KTS AT 0630Z
   CIMSS D-PRINT: 53 KTS AT 0630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 07S WILL CONTINUE TO TRACK WESTWARD PASSING
OVER THE NORTHERN TIP OF MADAGASCAR OVER THE NEXT 12 HOURS. AFTER 
PASSING BACK OVER WATER, THE SYSTEM WILL BEGIN TO ROUND THE CURVE OF 
A STR CENTERED OVER SOUTHEASTERN MADAGASCAR, CAUSING THE SYSTEM TO 
TRACK THROUGH THE MOZAMBIQUE CHANNEL. AT TAU 96 THE SYSTEM WILL TRACK 
SOUTHEASTWARD WHILE REMAINING UNDER THE STEERING INFLUENCE OF THE 
STR. THE SYSTEM WILL CONTINUE TO INTENSIFY UNTIL MAKING LANDFALL, 
WHICH WILL DISRUPT INTENSIFICATION DUE TO HIGH SHEAR AND TOPOGRAPHIC 
INTERACTION. HIGH SHEAR WILL CONTINUE TO HINDER INTENSIFICATION UNTIL 
TAU 48, AND TC 07S WILL PEAK AT AN INTENSITY OF 80KTS BY TAU 80. 
VERTICAL WIND SHEAR WILL INCREASE TO 20KTS ONCE AGAIN BY TAU 60, DUE 
TO AN APPROACHING UPPER-LEVEL TROUGH APPROACHING FROM THE SOUTHWEST. 
AS THE UPPER-LEVEL TROUGH CONTINUES EAST, THE SYSTEM WILL WEAKEN. 
EXTRATROPICAL TRANSITION WILL COMMENCE BY THE END OF THE FORECAST 
PERIOD. 

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN MOSTLY GOOD
AGREEMENT REGARDING EARLY TRACK FORECAST, BUT THE MID- TO LATE-
FORECAST GUIDANCE VARIES LARGELY BETWEEN GFS AND ECMWF. THE STR IN
THE GFS GUIDANCE TRACKS THE SYSTEM OVER LAND IN MOZAMBIQUE BETWEEN
TAU 48-108, ULTIMATELY INFLUENCING THE INTENSITY FORECAST AND CAUSING 
WEAKENING BEFORE TRACKING BACK OVER THE MOZAMBIQUE CHANNEL. ECMWF 
KEEPS THE SYSTEM OVER WATER, ALLOWING FOR INTENSIFICATION TO OCCUR 
UNTIL TAU 72 BEFORE MEETING HIGH SHEAR IN THE SOUTHERN MOZAMBIQUE 
CHANNEL. THE SMALL VARIATIONS IN THE TRACK GUIDANCE LEADS TO HIGH 
UNCERTAINTY IN THE MID- TO LATE-TERM INTENSITY FORECAST.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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