WTPN21 PGTW 070030
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 97W) REISSUED//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/060021Z JUL 21//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT (WTPN21 PGTW 060030)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 18.0N 110.7E TO 19.0N 105.5E
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 062330Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 18.0N 110.3E. THE SYSTEM IS MOVING WESTWARD AT 11 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 97W) PREVIOUSLY LOCATED 
NEAR 15.6N 112.5E IS NOW LOCATED NEAR 18.0N 110.3E, APPROXIMATELY 
122NM SOUTH OF HAIKOU, HAINAN. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY AND A 062052Z SSMI 85GHZ MICROWAVE IMAGE DEPICT A BROAD LOW 
LEVEL CIRCULATION (LLC) WITH FLARING CONVECTION DISPLACED TO THE WEST OF 
THE LLC. UPPER-LEVEL ANALYSIS REVEALS A MARGINAL ENVIRONMENT FOR 
DEVELOPMENT WITH MODERATE TO HIGH VERTICAL WIND SHEAR (VWS), WESTWARD 
OUTFLOW, AND WARM SEA SURFACE TEMPERATURES (30-31C). GLOBAL DYNAMIC 
MODELS ARE IN GOOD AGREEMENT THAT 97W WILL CONTINUE TO TRACK ALONG THE 
PERIPHERY OF A SUBTROPICAL RIDGE SITUATED TO THE NORTH AND NORTHEAST AS 
IT CONSOLIDATES AND TRACKS GENERALLY WESTWARD. MAXIMUM SUSTAINED SURFACE 
WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS 
ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A 
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH. THIS 
SUPERSEDES REF A.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 
080030Z.//
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