WTPS21 PGTW 101730
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT(INVEST 98P)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
200 NM EITHER SIDE OF A LINE FROM 18.2S 172.6W TO 21.9S 159.8W
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 30 TO 35 KNOTS. METSAT
IMAGERY AT 101430Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 18.5S 172.2W. THE SYSTEM IS MOVING EAST-SOUTHEASTWARD AT 12
KNOTS.
2. REMARKS:
THE AREA OF CONVECTION (INVEST 98P) PREVIOUSLY LOCATED NEAR 17.7S 175.5W 
IS NOW LOCATED NEAR 18.5S 172.2W, APPROXIMATELY 134 NM WEST-NORTHWEST OF 
NIUE. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS DEEP 
CONVECTION CONSOLIDATING AROUND A LOW LEVEL CIRCULATION CENTER (LLCC) 
EMBEDDED IN THE SOUTHERN PACIFIC CONVERGENCE ZONE. A 100926Z 
SCATTEROMETRY PASS SHOWS A WIDE SWATH OF GALE FORCE NORTHWESTERLIES ON 
THE EASTERN FLANK OF THE CIRCULATION WITH DEEP CONVECTION ESTABLISHING 
ITSELF OVER ALL QUADRANTS. THE ENVIRONMENTAL ANALYSIS REVEALS THAT THE 
SYSTEM EXISTS UNDER A NARROW ALLEY OF LOW VERTICAL WINDSHEAR (5-15KTS) 
WITH VIGOROUS POLEWARD OUTFLOW.  SEA SURFACE TEMPERATURES ARE 28-29 
DEGREES AND WILL REMAIN FAVORABLE UNTIL THE SYSTEM REACHES 22S LATITUDE, 
WHICH IS WHERE THE TEMPERATURES BEGIN TO DROP AND NOT BE CONDUCIVE FOR 
DEVELOPMENT AS A WARM CORE SYSTEM. THE GLOBAL MODELS SHOWS A VERTICALLY 
STACKED CIRCULATION THAT WILL CONTINUE TO DEVELOP OVER THE NEXT 24 HOURS. 
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 30 TO 35 KNOTS. MINIMUM 
SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 991 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 
110730Z.//
NNNN