WTPN21 PGTW 280830
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 19.9N 132.9E TO 24.8N 127.8E
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 18 TO 23 KNOTS. METSAT
IMAGERY AT 280600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 20.4N 132.3E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 08
KNOTS.
2. REMARKS:
THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR 19.6N
132.9E, IS NOW LOCATED NEAR 20.4N 132.3E, APPROXIMATELY 435 NM
SOUTHEAST OF KADENA AFB. ANIMATED MULTISPECTRAL IMAGERY CLEARLY SHOWS
PERSISTENT DEEP CONVECTION BUILDING IN THE SOUTHERN ARC OF THE
SYSTEM WITH ADDITIONAL FLARING CONVECTION FORMING TO THE NORTHEAST.
A 280546Z SSMI 85GHZ IMAGE DEPICTS THE SAME BUILDING DEEP CONVECTION
AND THE IMPROVED SYMMETRY IN THE LLCC. VWS REMAINS LOW (10-15 KNOTS)
DIRECTLY OVER THE LLCC, WITH STRONG DIVERGENCE ALOFT AND NEAR-RADIAL
OUTFLOW. SSTS REMAIN WARM (28-29C) AND WILL SUPPORT FURTHER
DEVELOPMENT. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 90W WILL REACH
TROPICAL DEPRESSION STRENGTH AS IT TRACKS NORTHWEST TOWARDS OKINAWA,
WITH SOME VARIATION IN TIMING. NAVGEM, GFS, AND UKMET ALL SHOW 90W
BECOMING A TD WITHIN 24HRS, WITH THE ECMWF AND JGSM FOLLOWING
SHORTLY AFTER. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18
TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005
MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
290830Z.//
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