WTPN22 PGTW 231100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/230951ZNOV2009//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 200 NM RADIUS OF 4.5N 107.2E 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 15 TO 20 KNOTS. METSAT IMAGERY AT 231030Z INDICATES A
CIRCULATION CENTER IS LOCATED NEAR 4.5N 107.2E. THE SYSTEM IS
MOVING NORTH-NORTHEASTWARD AT 09 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 3.7N
107.4E, IS NOW LOCATED NEAR 4.5N 107.2E, APPROXIMATELY 280 NM
NORTHEAST OF SINGAPORE. ANIMATED SATELLITE IMAGERY SHOWS DEEP
CONVECTION CONSOLIDATING NEAR A QUICKLY IMPROVING LOW LEVEL
CIRCULATION CENTER (LLCC). A 230156Z ASCAT PASS SHOWS AN
INCREASINGLY SYMMETRIC LLCC WITH CENTER WINDS OF 10 TO 15 KNOTS.
ADDITIONALLY, THE ASCAT PASS SHOWS 30-KNOT PERIPHERIAL WINDS TO THE
NORTHWEST (ASSOCIATED WITH THE NORTHEASTERLY COLD SURGE THROUGH THE
SOUTH CHINA SEA) AND 20-25 KNOTS TO THE SOUTHWEST AND SOUTHEAST OF
THE SYSTEM CENTER. FINALLY, A 230931Z AMSU MICROWAVE IMAGE DEPICTS
MULTIPLE CONVECTIVE BANDS CONVERGING TOWARDS THE LLCC, ILLUSTRATING
THE IMPROVING NATURE OF THE CIRCULATION. UPPER-LEVEL ANALYSIS
INDICATES THE SYSTEM IS LOCATED EQUATORWARD OF THE SUBTROPICAL RIDGE
AXIS WITH RADIAL OUTFLOW AND FAVORABLY LOW VERTICAL WIND SHEAR.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. DUE TO
CONSOLIDATION OF DEEP CONVECTION OVER THE IMPROVING NATURE OF THE
LLCC, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
241100Z.
4. SEE REF A (WTPN21 PGTW 231000) FOR DETAILS ON A TROPICAL CYCLONE
FORMATION ALERT LOCATED NEAR 9.5N 127.4E//