WTXS21 PGTW 210530
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 9.1S 100.0E TO 10.9S 104.2E
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 27 TO 32 KNOTS. METSAT IM-
AGERY AT 210000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 9.2S 100.3E.  THE SYSTEM IS MOVING EASTWARD AT 15 KNOTS.
2. REMARKS: AN AREA OF CONVECTION NEAR 9.2S 100.3E, APPROXIMATELY
265NM NORTHEAST OF THE COCOS ISLANDS, HAS PERSISTED OVER THE PAST
12 HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A
210010Z SSMI MICROWAVE IMAGE DEPICT ORGANIZED DEEP CONVECTION
DEVELOPING AROUND A CONSOLIDATING LOW LEVEL CIRCULATION CENTER
(LLCC). STRONG SURFACE WESTERLIES TO THE NORTH OF THE DISTURBANCE
ARE HELPING TO ENHANCE LOW LEVEL VORTICITY. THE DISTURBANCE LIES
UNDER A REGION OF LOW TO MODERATE VERTICAL WIND SHEAR WITH GOOD
POLEWARD OUTFLOW AHEAD OF AN UPPER-LEVEL MIDLATITUDE TROUGH
LOCATED TO THE SOUTHWEST. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 27 TO 32 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1000 MB. BASED ON IMPROVING LOW-LEVEL ORGAN-
IZATION AND UPPER LEVEL SUPPORT, 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 220530Z.//