WTPN21 PHNC 192230
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1.
FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
240 NM EITHER SIDE OF A LINE FROM 12.5N 90.0W TO 15.1N 101.0W
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 15 TO 20 KNOTS. METSAT IM-
AGERY AT 192130Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.5N 90.6W. THE SYSTEM IS MOVING WESTWARD AT 12 KNOTS.
2. REMARKS: AN AREA OF CONVECTION HAS PERSISTED NEAR 12.5N 90.6W,
APPROXIMATELY 115 NM SOUTHWEST OF SAN SALVADOR, EL SALVADOR.
RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES IMPROVED
CONSOLIDATION OVER THE PAST 12 HOURS WITH A SOMEWHAT BROAD LOW-
LEVEL CIRCULATION CENTER (LLCC). A 191630Z AMSU IMAGE DEPICTS
DEVELOPING CONVECTIVE BANDING NORTHWEST WRAPPING INTO THE SOUTH
QUADRANT. THE LLCC IS LOCATED IN A MARGINAL ENVIRONMENT, SOUTH
OF AN UPPER-LEVEL ANTICYCLONE, WITH STRONG DIFFLUENCE AND
MODERATE EASTERLY VERTICAL WIND SHEAR (VWS). OVER THE NEXT 18-36
HOURS, THE VWS IS EXPECTED TO DECREASE ALLOWING THE SYSTEM TO
DEVELOP. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO
20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005
MB. DUE TO THE IMPROVEMENT IN CONVECTIVE BANDING AND DEFINED
LLCC, THE
POTENTIAL FOR 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 202230Z.//
BT