WDXS31 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (ELEVEN) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.1S 62.3E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 336 NM EAST-NORTHEAST OF PORT LOUIS,
MAURITIUS
   MOVEMENT PAST 6 HOURS: WESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM
CONTINUES TO STRUGGLE AS IT TRACKS ALONG THE NORTHERN PERIPHERY OF
THE SUBTROPICAL RIDGE (STR) TO THE SOUTH AND STRADDLING A ZONE OF
MODERATE VERTICAL WIND SHEAR. THE CENTRAL DENSE OVERCAST IS
UNDERGOING A DIURNAL FLAREUP AND IS OBSCURING THE LOW LEVEL
CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE USING LOW CLOUD TRACING INTO THE OBSCURED LLCC. THE
INITIAL INTENSITY IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE
AUTOMATED CIMSS ESTIMATES AND REFLECTS THE SUSTAINED CONVECTIVE
SIGNATURE. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH WARM SST
AND MODERATE WESTWARD OUTFLOW OFFSET BY MODERATE VWS AND DRY AIR IN
THE MID-LEVELS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: STR TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   CIMSS SATCON: 35 KTS AT 312330Z
   CIMSS ADT: 33 KTS AT 010000Z
   CIMSS AIDT: 33 KTS AT 010000Z
   CIMSS ADT: 34 KTS AT 010030Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE WESTWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 11S WILL CONTINUE GENERALLY WESTWARD UNDER
THE STEERING STR. AFTER TAU 36, A SECONDARY STR BUILDING FROM THE
SOUTHWEST WILL ASSUME STEERING AND DRIVE THE CYCLONE ON A MORE
WEST-NORTHWESTWARD TRACK, MAKING LANDFALL OVER NORTHEASTERN
MADAGASCAR JUST AFTER TAU 72. THE MARGINAL ENVIRONMENT WILL, AT
BEST, MAINTAIN THE CURRENT INTENSITY UP TO TAU 36. AFTERWARD,
DECREASING MID-LEVEL DRY AIR INTRUSION AND VWS WILL PROMOTE
INTENSIFICATION TO A PEAK OF 50KTS BY TAU 72. AFTER LANDFALL, THE
RUGGED TERRAIN WILL RAPIDLY ERODE THE SYSTEM TO DISSIPATION BY TAU
120. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT
WITH A GRADUAL AND EVEN SPREAD TO 190NM AT TAU 72 AND 202NM AT TAU
120. HOWEVER, GIVEN THE UNCERTAINTY IN THE FORECAST INTENSITIES
THAT CAN ALSO IMPACT THE TRACK, THERE IS ONLY MEDIUM CONFIDENCE TO
THE JTWC TRACK AND INTENSITY FORECASTS. 

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