JTWC upgrades to GOOD and puts out a tropical cyclone formation alert:
WTPN21 PGTW 011500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
150 NM EITHER SIDE OF A LINE FROM 14.6N 142.3E TO 20.4N 136.3E
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 17 TO 22 KNOTS. METSAT IM-
AGERY AT 011200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 15.2N 142.1E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT
09 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.8N
142.8E IS NOW LOCATED NEAR 15.2N 142.1E, APPROXIMATELY 190 NM
NORTHWEST OF GUAM. ANIMATED INFRARED SATELLITE IMAGERY SHOWS
INCREASED CENTRAL CONVECTION OVER A DEVELOPING LOW LEVEL CIRCULATION
CENTER (LLCC) AND A 010941Z SSMIS MICROWAVE SATELLITE IMAGE SHOWS
IMPROVED LOW LEVEL INFLOW. THE SYSTEM IS LOCATED IN AN AREA OF LOW
VERTICAL WIND SHEAR AND GOOD UPPER LEVEL DIVERGENCE, FAVORABLE FOR
DEVELOPMENT. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 17 TO
22 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007
MB. DUE TO THE IMPROVED UPPER LEVEL ENVIRONMENT AND INCREASE IN
CENTRAL CONVECTION, 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
021500Z.//
NNNN
![Image](http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/warnings/wp9310.gif)
![Image](http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/satshots/93W_011500sair.jpg)