WTPS21 PGTW 260100
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 200 NM RADIUS OF 7.8S 135.8E WITHIN THE NEXT 12 TO 24 HOURS.
AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CY-
CLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO
BE 25 TO 30 KNOTS. METSAT IMAGERY AT 260030Z INDICATES THAT A
CIRCULATION CENTER IS LOCATED NEAR 7.8S 135.8E. THE SYSTEM IS
MOVING EAST-NORTHEASTWARD AT 03 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 8.0S
136.0E, IS NOW LOCATED NEAR 7.8S 135.8E, APPROXIMATELY 410 NM NORTH-
EAST OF DARWIN, AUSTRALIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
INDICATES IMPROVED CONSOLIDATION WITH MULTIPLE DEEP CONVECTIVE BANDS
WRAPPING INTO A DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). A
252204Z SSMI/S IMAGE DEPICTS CONVECTIVE BANDING WRAPPING FROM THE
WESTERN QUADRANT INTO THE EASTERN QUADRANT. RECENT SCATTEROMETER
DATA HAS BEEN UNAVAILABLE, HOWEVER, A 25/18Z SHIP REPORT FROM
VDRX2, LOCATED ABOUT 100 NM SSW, INDICATED WINDS OF 110/24 AND
SLP OF 1008.5 MB. THIS SUPPORTS THE ESTIMATED 25-30 KNOT MAXIMUM
SUSTAINED SURFACE WINDS. THE LLCC IS LOCATED JUST EQUATORWARD OF
THE UPPER-LEVEL SUBTROPICAL RIDGE AXIS UNDER MODERATE VERTICAL
WIND SHEAR, HOWEVER, ANIMATED WATER VAPOR IMAGERY SHOWS IMPROVED
POLEWARD OUTFLOW ENHANCED BY MIDLATITUDE WESTERLIES OVER NORTHERN
AUSTRALIA. ADDITIONALLY, SST, OCEAN HEAT CONTENT AND MOISTURE ARE
FAVORABLE FOR FURTHER DEVELOPMENT. TRACK MOTION HAS BEEN SLOW AND
ERRATIC BUT THE SYSTEM IS EXPECTED TO BEGIN TRACKING WESTWARD TO
NORTHWESTWARD WITHIN TH ENEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE
IS ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT
OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 270100Z.//