WTPN21 PGTW 090600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 22.4N 156.2E TO 25.6N 159.9E
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
IMAGERY AT 080900Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 22.5N 156.4E. THE SYSTEM IS MOVING NORTHEASTWARD AT 18
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 98W) PREVIOUSLY LOCATED 
NEAR 19.6N 150.5E IS NOW LOCATED NEAR 22.5N 156.4E, APPROXIMATELY 608 
NM WEST-NORTHWEST OF WAKE ISLAND. ANIMATED MULTISPECTRAL IMAGERY (MSI) 
DEPICTS A DEVELOPED LOW-LEVEL CIRCULATION CENTER (LLCC), OBSCURED BY 
UPPER-LEVEL CONVECTION EMBEDDED WITHIN A LONGWAVE TROUGH. A PARTIAL 
082301Z ASCAT-C PASS REVEALED AN ELONGATED AND RELATIVELY WEAK 
CIRCULATION EMBEDDED WITHIN A BAND OF STRONG SOUTHWESTERLY MONSOONAL 
FLOW ON THE EASTERN FLANK OF A LARGE CYCLONIC GYRE. MAXIMUM WINDS IN 
THE ASCAT IMAGERY ARE 20-25 KNOTS IN THE EASTERN HEMISPHERE OF THE 
CIRCULATION. ENVIRONMENTAL ANALYSIS SHOWS FAVORABLE CONDITIONS FOR 
DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (10 TO 15KTS), WARM SEA 
SURFACE TEMPERATURES (29 TO 30 C), AND GOOD POLEWARD OUTFLOW. 
DETERMINISTIC MODELS BRIEFLY DEVELOP 98W INTO A WEAK TROPICAL 
DEPRESSION THAT GENERALLY TRACKS NORTH-NORTHEASTWARD ALONG THE 
EASTERN PERIPHERY OF THE CYCLONIC GYRE PATTERN. FOR ENSEMBLE MODELS, 
ECENS INDICATES A HIGHER INTENSITY OF 98W AS OPPOSED TO GEFS 
MAINTAINING A LOWER CONFIDENCE AND INTENSITY. BOTH HOWEVER, AGREE 
UPON THE NORTH-NORTHEAST TRACK OF 98W OVER THE NEXT 24 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 17 TO 22 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 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 
100600Z.//
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