WTXS21 PGTW 230200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 99S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
130 NM EITHER SIDE OF A LINE FROM 16.0S 109.1E TO 20.6S 103.2E
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 28 TO 33 KNOTS. METSAT
IMAGERY AT 230000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 16.2S 108.6E. THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 12
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 99S) PREVIOUSLY LOCATED NEAR 
15.7S 109.7E IS NOW LOCATED NEAR 16.2S 108.6E, APPROXIMATELY 476 NM 
NORTHWEST OF LEARMONTH, AUSTRALIA. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY DEPICTS A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) AND A 
GMI 89GHZ MICROWAVE IMAGE ALSO DEPICTS DEEP CONVECTIVE CURVED BANDING TO 
THE NORTH OF THE LLCC, THOUGH THE LLCC REMAINS DISPLACED A BIT TO THE EAST 
OF THE DEEP CONVECTIVE MASS. A 221358Z ASCAT-C SCATTEROMETERY PASS REVEALS 
25-30 KNOT WINDS WRAPPING INTO THE LLCC, WITH NORTH TO SOUTHEASTERLY 20-25 
KNOT WIND FIELDS TO THE EAST AND SOUTH OF THE LLCC AND CONFIRMS THE FACT 
THAT THE LLCC IS IN FACT NOT VERTICALLY ALIGNED WITH THE CONVECTION. 
ENVIRONMENTAL ANALYSIS INDICATES THAT INVEST 99S IS IN A FAVORABLE 
ENVIRONMENT FOR FURTHER DEVELOPMENT DUE TO WARM (28-29C) SEA SURFACE 
TEMPERATURES, LOW TO MODERATE (15-20 KNOTS) VERTICAL WIND SHEAR, AND GOOD 
OUTFLOW ALOFT. GLOBAL MODELS ARE NOT IN GOOD AGREEMENT WITH THE POTENTIAL 
DEVELOPMENT OF 99S. GFS IS THE PRIMARY MODEL SHOWING QUICK CONSOLIDATION 
OVER THE NEXT 24-36 HOURS. THE GFS AND ECMWF ENSEMBLES ARE IN GOOD 
AGREEMENT HOWEVER IN THE GENERAL SOUTH-SOUTHWESTWARD TRACK OVER THE NEXT 
24-36 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 998 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 
240200Z.//
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