WTPN21 PHNC 270200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 90C)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 10.9N 143.7W TO 11.2N 150.2W 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 20 TO 25 KNOTS. METSAT IMAGERY AT 270200Z INDICATES THAT 
A CIRCULATION CENTER IS LOCATED NEAR 10.9N 144.1W. THE SYSTEM IS MOVING 
WESTWARD AT 11 KNOTS.
2. REMARKS: AN AREA OF CONVECTION (INVEST 90C) IS LOCATED NEAR 10.9N 
144.1W, APPROXIMATELY 826NM SOUTHEAST OF HILO, HAWAII. ANIMATED 
MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A CONSOLIDATING LOW LEVEL 
CIRCULATION CENTER (LLCC), OBSCURED BY PERSISTENT DEEP CONVECTION 
BUILDING OVER THE CENTER. A RECENT 262231Z AMSR2 89 GHZ PARTIAL PASS 
INDICATES A DEFINED LLCC WITH DEEP CONVECTION BUILDING OVER THE CENTER 
WITH LOW-LEVEL BANDING. ENVIRONMENTAL ANALYSIS REVEALS A MARGINAL 
ENVIRONMENT FOR DEVELOPMENT WITH GOOD EQUATORWARD UPPER-LEVEL OUTFLOW, 
WARM SEA SURFACE TEMPERATURES (SST) OF 28-29C, OFFSET BY LOW TO MODERATE 
VERTICAL WIND SHEAR (VWS) OF 15-20 KNOTS. DETERMINISTIC MODELS AND 
ENSEMBLE MODELS ARE IN AGREEMENT THAT INVEST 90C WILL MOVE WESTWARD AS 
IT CONSOLIDATE OVER THE NEXT 24 HOURS, HOWEVER GFS AND ECMWF ARE BOTH IN 
AGREEMENT THAT 90C WILL REACH WARNING CRITERIA IN THE NEXT 48 HOURS. 
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM 
SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 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 
280200Z.//
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