WTPN21 PHNC 281200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98E)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 8.2N 131.9W TO 12.1N 131.5W
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 23 TO 28 KNOTS. METSAT
IMAGERY AT 281200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 10.2N 131.8W. THE SYSTEM IS MOVING WESTWARD AT 05
KNOTS.
2. REMARKS: AN AREA OF CONVECTION (INVEST 98E) HAS PERSISTED NEAR 10.2N 
131.8W, APPROXIMATELY 1462 NM EAST-SOUTHEAST OF HILO. ENHANCED 
INFRARED SATELLITE IMAGERY (EIR) DEPICTS A PARTIALLY EXPOSED LOW LEVEL 
CIRCULATION CENTER (LLCC) WITH BUILDING DEEP CONVECTION, AND MID TO LOW 
LEVEL CLOUD BANDS WRAPPED AROUND THE SOUTHWEST INTO THE LLCC. A PARTIAL 
280651Z METOP-C ASCAT IMAGE REVEALS THE DISORGANIZED TROUGHING ALONG THE 
WESTERN SEMICIRCLE OF THE LLCC WITH RELATIVELY LIGHT WINDS OF 10-15 
KNOTS ALONG THE WESTERN PERIPHERY. ENVIRONMENTAL ANALYSIS INDICATES A 
MARGINALLY FAVORABLE AREA FOR DEVELOPMENT DEFINED BY MODERATE VERTICAL 
WIND SHEAR (VWS) OF 15-20 KNOTS, WEAK EQUATORWARD OUTFLOW, AND WARM SEA 
SURFACE TEMPERATURES OF 27-28 C. DETERMINISTIC AND ENSEMBLE MODELS ARE 
IN AGREEMENT THAT 98E WILL TRACK WESTWARD WHILE STEADILY CONSOLIDATING 
AND INTENSIFYING OVER THE NEXT 24-36 HOURS. MAXIMUM SUSTAINED SURFACE 
WINDS ARE ESTIMATED AT 23 TO 28 KNOTS. MINIMUM SEA LEVEL PRESSURE IS 
ESTIMATED TO BE NEAR 1009 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A 
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 23 TO 28 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1009 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 
291200Z.//
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