WTXS21 PGTW 041800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91S) REISSUED//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/031751ZJAN2026//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 9.4S 96.9E TO 15.1S 96.9E
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 27 TO 32 KNOTS. METSAT
IMAGERY AT 041800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 9.5S 96.9E. THE SYSTEM IS MOVING SOUTHEASTWARD AT 12
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED NEAR 
8.6S 95.9E IS NOW LOCATED NEAR 9.5S 96.9E, APPROXIMATELY 160 NM NORTH OF 
THE COCOS ISLANDS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS 
DEEP CONVECTION BUILDING OVER THE NORTHERN AND WESTERN PORTIONS OF A 
CONSOLIDATING LOW LEVEL CIRCULATION EVIDENT IN A 041420Z METOP-B ASCAT 
PASS, WHICH ALSO SHOWS INCREASING NEAR-CENTER WIND SPEEDS SURROUNDING 
THE CIRCULATION CENTER. ENVIRONMENTAL ANALYSIS REVEALS MARGINALLY 
FAVORABLE CONDITIONS FOR DEVELOPMENT WITH WARM (28-29C) SEA SURFACE 
TEMPERATURES AND FAVORABLE POLEWARD AND WESTWARD OUTFLOW ALOFT OFFSET BY 
MODERATE TO HIGH (15-20 KTS) EAST-NORTHEASTERLY VERTICAL WIND SHEAR. 
GLOBAL DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD AGREEMENT THAT 91S 
WILL STEADILY INTENSIFY AS IT CONTINUES TO TRANSIT POLEWARD. MAXIMUM 
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27 TO 32 KNOTS. MINIMUM SEA 
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE 
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS 
REMAINS HIGH. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27 TO 32 
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS REMAINS HIGH. THIS SUPERSEDES REF A (WTXS21 
PGTW 031800).
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 
051800Z.//
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