MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 11.7S 69.2E TO 14.4S 67.3E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IM-
AGERY AT 030730Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.9S 68.9E. THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 06
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.6S
69.4E, IS NOW LOCATED NEAR 11.9S 68.9E, APPROXIMATELY 340 NM
SOUTHWEST OF DIEGO GARCIA. RECENT ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A WELL DEFINED LOW LEVEL CIRCULATION CENTER (LLCC)
WITH FLARING DEEP CENTRAL CONVECTION AND FORMATIVE BANDING OVER THE
WESTERN SEMICIRCLE OF THE LLCC. A 030303Z SSMIS 37 GHZ IMAGE DEPICTS
TIGHTLY CURVED BANDING JUST TO THE WEST OF THE LLCC WITH WELL
DEFINED, YET CONVECTIVELY WEAKER, LOW-LEVEL BANDS TO THE SOUTHEAST.
A 030511Z ASCAT PASS INDICATES 25-30 KNOT WINDS NEAR THE LLCC WITH
STRONGER WINDS TO THE NORTHWEST ASSOCIATED WITH THE ABOVEMENTIONED
FORMATIVE WESTERN BANDS. UPPER LEVEL ANALYSIS INDICATES THAT THE
LLCC IS LESS THAN 05 DEGREES EQUATORWARD OF THE EAST-WEST ORIENTATED
SUBTROPICAL RIDGE AXIS WHICH DOMINATES THE MAJORITY OF THE
EQUATORIAL SOUTHERN INDIAN OCEAN. VERTICAL WINDSHEAR (VWS) IS
ESTIMATED AT 20-25 KNOTS FROM THE EAST. HOWEVER, AS THE SYSTEM
SLOWLY TRACKS SOUTHWARD TOWARD THE RIDGE AXIS, VWS SHOULD SUBSIDE
AND MAY ALLOW A WINDOW FOR FURTHER DEVELOPMENT. THE LLCC IS LOCATED
UNDER AN AREA OF GOOD DIVERGENCE ALOFT AND RECENT ANIMATED WATER
VAPOR IMAGERY DEPICTS GOOD OUTFLOW WITH SOME ENHANCEMENT ON THE
POLEWARD SIDE ASSOCIATED WITH TROUGHING TO THE SOUTHEAST. SEA
SURFACE TEMPERATURES ARE FAVORABLE FOR DEVELOPMENT AT 27-28 DEGREES
CELSIUS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB.
DUE TO INCREASED CONSOLIDATION OF THE LLCC, FORMATIVE BANDING, AND
RECENT SCATTEROMETRY DATA, THE POTENTIAL OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
040830Z.//
![Image](http://www.nrlmry.navy.mil/htdocs_dyn_pregen_sat/PUBLIC/tc_pages/thumbs/medium/tc12/SHEM/98S.INVEST/vis/geo/1km/20111203.1230.meteo7.x.vis1km.98SINVEST.30kts-1000mb-119S-689E.100pc.jpg)