WDXS31 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 07S (DIKELEDI) WARNING 
NR 008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.8S 41.1E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 26 NM EAST-SOUTHEAST OF NACALA, MOZAMBIQUE
   MOVEMENT PAST 6 HOURS: WESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 07S RAPIDLY APPROACHING THE COAST OF MOZAMBIQUE.
LOW-LEVEL CLOUD BANDING IS VISIBLE IN THE SOUTHERN PERIPHERY OF THE
SYSTEM DUE TO MODERATE (10-15KT) VERTICAL WIND SHEAR (VWS) FROM THE
SOUTH. WATER VAPOR IMAGERY REVEALS RADIAL OUTFLOW, BUT THE
UPPER-LEVEL FLOW IS STRONGEST EQUATORWARD AND WESTWARD OF THE
LOW-LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON A 130601Z METOP-B ASCAT IMAGERY REVEALING
THE CIRCULATION CENTER, ACCOMPANIED BY THE AFOREMENTIONED ANIMATED
MSI. THE INITIAL INTENSITY OF 70 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES BELOW, GIVEN
THAT THE CENTER OF THE ASCAT PASS WAS RAIN-FLAGGED UNDER THE DEEP
CONVECTION.

INITIAL WIND RADII BASIS: 130601Z SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: A DEEP-LAYER SUBTROPICAL RIDGE TO THE
SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 67 KTS AT 130630Z
   CIMSS ADT: 79 KTS AT 130600Z
   CIMSS AIDT: 84 KTS AT 130630Z
   CIMSS D-PRINT: 62 KTS AT 130630Z

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

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: TC 07S HAS TRACKED FARTHER WEST THAN
WAS PREVIOUSLY FORECASTED AND IS NOW ANTICIPATED TO MAKE LANDFALL
WITHIN THE NEXT 12 HOURS. THE TOPOGRAPHIC INTERACTION IN THE FIRST
24 HOURS OF THE FORECAST WILL LEAD TO WEAKENING BEFORE THE SYSTEM
COMES BACK OVER WATER.

FORECAST DISCUSSION: TC 08S WILL MAKE LANDFALL IN THE VICINITY OF
NACALA, MOZAMBIQUE WITHIN THE NEXT 12 HOURS, AND REMAIN OVER LAND
UNTIL TAU 24. THE TOPOGRAPHIC INFLUENCE WILL CAUSE SLIGHT
WEAKENING, HOWEVER, THE ENVIRONMENT IS EXPECTED TO REMAIN MOIST
AND UPPER-LEVEL DIVERGENCE WILL IMPROVE. AS THE SYSTEM CROSSES OVER
THE RIDGE AXIS BETWEEN TAU 24-48, A POLEWARD OUTFLOW CHANNEL WILL
DEVELOP, ENHANCING THE RATE OF INTENSIFICATION AS THE COL REGION
TO THE SOUTH PROPAGATES EASTWARD. VWS WILL DECREASE AS THE SYSTEM
MOVES SOUTH-SOUTHWESTWARD AWAY FROM LAND, LEADING TO A PEAK
INTENSITY OF 90KTS BY TAU 72. AROUND TAU 96-120, AN APPROACHING
UPPER-LEVEL TROUGH WILL INITIATE EXTRATROPICAL TRANSITION LEADING
TO GRADUAL WEAKENING TO 70KTS AS THE SYSTEM BECOMES FULLY
EXTRATROPICAL.

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE LEADS
TO LOW CONFIDENCE AS THE MODEL SOLUTIONS HAVE GONE BACK AND FORTH
ON WHETHER OR NOT THE SYSTEM WILL REMAIN OVER WATER OR OVER LAND.
THE ENSEMBLE GUIDANCE OF COAMPS-TC, GEFS, AND ECENS HAVE ALL
STRONGLY INDICATED A TRACK LYING OVER THE MOZAMBIQUE CHANNEL, WHICH
HAVE ALL PROVEN NOT TO PLAY OUT. THE MOST RECENT RUNS OF ALL OF THE
ENSEMBLE GUIDANCE REPRESENT APPROXIMATELY 50 PERCENT OF MEMBERS
PASSING OVER LAND. GFS HAS BEEN THE STANDOUT PERFORMER FORECASTING
CONSISTENTLY THAT THE SYSTEM WILL PASS OVER MOZAMBIQUE, AND THE
JTWC FORECAST TRACK NOW FAVORS GFS. THE INTENSITY GUIDANCE IS
HIGHLY DEPENDENT ON THE EARLY-TERM WEAKENING IN THE FORECAST AND
SHOWS A VARIETY OF SOLUTIONS BETWEEN A PEAK AS HIGH AS 120KTS
(HWRF) AND AS LOW AS 70KTS (GFS). 

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