WTXS21 PGTW 061200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 16.2S 55.1E TO 16.5S 50.3E
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
IMAGERY AT 030600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 16.2S 54.8E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 03
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97S) PREVIOUSLY LOCATED 
NEAR 16.5S 54.9E IS NOW LOCATED NEAR 16.2S 54.8E, APPROXIMATELY 
328NM EAST OF TOAMASINA, MADAGASCAR. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY (MSI) AND A 060950Z GMI 89GHZ MICROWAVE IMAGE 
DEPICT A WELL DEFINED LOW LEVEL CIRCULATION CENTER (LLCC)WITH 
FRAGMENTED CONVECTIVE BANDING BEGINNING TO WRAP INTO THE LLCC, WHILE 
A RELATIVELY RECENT 060604Z ASCAT PASS REVEALS A SWATH OF 25 KNOT 
WINDS WRAPPING INTO THE LLCC FROM THE SOUTH. ANALYSIS INDICATES THE 
ENVIRONMENT IS FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT WITH 
BURGEONING RADIAL OUTFLOW, LOW VERTICAL WIND SHEAR (05-15KTS), AND 
WARM SEA SURFACE TEMPERATURES (28-29C). GLOBAL MODELS ARE IN GOOD 
AGREEMENT THAT 97S WILL REMAIN GENERALLY QUASI-STATIONARY AND 
MEANDER WEST TOWARDS MADAGASCAR, HOWEVER THE TIMING OF WHEN 97S 
REACHES WARNING CRITERIA DIFFERS, WITH GFS INTENSIFYING THE 
DISTURBANCE TO A TROPICAL STORM WITHIN 24-36 HOURS WHILE ECMWF HOLDS 
THE INTENSITY BELOW TROPICAL STORM STRENGTH UNTIL LANDFALL. MAXIMUM 
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA 
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR 
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 
HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 
071200Z.
//
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