WDXS31 PGTW 031500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FAIDA) WARNING NR 
013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.1S 50.5E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 177 NM EAST-NORTHEAST OF ANTANANARIVO,
MADAGASCAR
   MOVEMENT PAST 6 HOURS: WESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 11S (FAIDA) WITH STRONG BURSTS OF CONVECTION JUST OFF THE
COAST OF MADAGASCAR AND IMPROVED EQUATORWARD OUTFLOW EVIDENT BY
CIRRUS FILAMENTS EXTENDING OUTWARD FROM THE SYSTEM. THE LOW-LEVEL
CIRCULATION CENTER IS DIFFUCULT TO PINPOINT BUT IS ASSESSED TO BE
EAST OF THE CONVECTIVE BURSTS WITH VERY LOW CONFIDENCE. A 030621Z
ASCAT-C IMAGE REVEALS THAT THE STRONGER WINDS ARE CONFINED TO THE
WESTERN QUADRANTS OF THE VORTEX. THE INITIAL INTENSITY OF 40 KTS
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND
OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. THE ASCAT-C IMAGE 
SUGGESTS THAT THE WIND FIELD IS WEAKER THAN WHAT MANY OF THE 
INTENSITY ESTIMATES ARE AT.

INITIAL WIND RADII BASIS: PERSISTENCE FROM EARLIER SCATTEROMETER
DATA. 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF AN EXTENSTION OF
A SUBTROPICAL RIDGE (STR) CENTERED TO THE SOUTHWEST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   FMEE: T2.5 - 35 KTS
   CIMSS ADT: 55 KTS AT 031200Z
   CIMSS AIDT: 50 KTS AT 031200Z
   CIMSS DPRINT: 50 KTS AT 031200Z
   CIMSS DMINT: 36 KTS AT 031235Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: 11S IS FORECAST TO CONTINUE TRACKING GENERALLY
WESTWARD, ALONG THE NORTHERN PERIPHERY OF THE STR THROUGHOUT THE
FORECAST PERIOD. LANDFALL IS ANTICIPATED TO OCCUR JUST AFTER TAU
12, NORTH OF TOAMASINA. ENTRY INTO THE MOZAMBIQUE CHANNEL IS
FORECAST TO OCCUR AROUND TAU 60. THEN A SECOND LANDFALL, WITHIN
MOZAMBIQUE IS EXPECTED SOON AFTER TAU 120. REGARDING INTENSITY, 11S
IS FORECAST TO MAINTAIN INTENSITY THROUGH TAU 12, BEFORE MAKING
LANDFALL IN MADAGASCAR. TERRAIN INTERACTION WILL THEN RAPIDLY
WEAKEN THE SYSTEM AS IT CROSSES CENTRAL MADAGASCAR. THERE IS A
DEFINITE POSSIBLITY THAT THE SYSTEM WILL COMPLETELY DISSIPATE
BEFORE REACHING THE MOZAMBIQUE CHANNEL. IF THE SYSTEM IS ABLE TO
ENTER THE CHANNEL, THE ENVIRONMENT WILL BECOME MUCH MORE FAVORABLE
WITH VERY WARM SEA SURFACE TEMPERATURES AND LOW VERTICAL WIND
SHEAR. AS A RESULT, THE JTWC FORECAST CALLS FOR INTENSIFICATION AS
THE SYSTEM APPRAOCHES MOZAMBIQUE.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY POOR
AGREEMENT ACROSS THE BOARD. TRACK GUIDANCE SPREADS OUT
SIGNIFICANTLY AFTER LANDFALL, WITH A 289 NM CROSS-TRACK SPREAD AT
TAU 48. ECMWF DETERMINISTIC LOSES THE VORTEX BEFORE IT IS ABLE TO
ENTER THE CHANNEL. THE REMINDER OF GUIDANCE DOES TRACK THE SYSTEM
INTO THE CHANNEL, BUT WITH SIGNIFICANT CROSS-TRACK AND ALONG-TRACK
SPREAD AFTERWARDS. AS A RESULT, THE JTWC TRACK FORECAST IS PLACED
WITH OVERALL LOW CONFIDENCE. INTENSITY GUIDANCE PAINTS A SIMILAR
PICTURE, WITH MODELS VARYING DUE TO DIFFERENCES IN TIMING OVER LAND
VS WATER. THERE IS A GENERAL TREND IN WEAKEING OVER LAND AND THEN
REINTENSIFICATION WITHIN THE CHANNEL THOUGH. THE JTWC INTENSITY
FORECAST IS PLACED CLOSE TO CONSENSUS WITH LOW CONFIDENCE. 

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