WTXS21 PGTW 162100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 99S) REISSUED//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/162059Z JAN 20//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 162100)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 12.5S 64.8E TO 13.4S 58.3E
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 28 TO 33 KNOTS. METSAT
IMAGERY AT 161800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 12.5S 64.4E. THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 08
KNOTS.
2. REMARKS: ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 
161438Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS CONVECTIVE BANDING 
WRAPPING INTO AN ELONGATED LOW LEVEL CIRCULATION CENTER (LLCC) WITH 
FLARING CONVECTION IN THE WESTERN SEMI-CIRCLE. INVEST 99S IS IN A 
FAVORABLE ENVIRONMENT FOR TROPICAL DEVELOPMENT WITH ROBUST WESTWARD 
OUTFLOW ALOFT AND WARM (29-30C) SEA SURFACE TEMPERATURES, OFFSET BY 
STRONG (35-40KT) VERTICAL WIND SHEAR. GLOBAL MODELS ARE IN GOOD 
AGREEMENT THAT INVEST 99S WILL CONTINUE TO TRACK WEST-SOUTHWESTWARD 
AS IT SLOWLY INTENSIFIES. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED 
TO BE NEAR 998 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 
172100Z.//
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