WTXS21 PGTW 031800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 8.0S 91.5E TO 10.7S 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 031800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 8.1S 91.6E. THE SYSTEM IS MOVING EAST-NORTHEASTWARD AT 18
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED NEAR 
8.7S 89.9E IS NOW LOCATED NEAR 8.1S 91.6E, APPROXIMATELY 395 NM 
NORTHWEST OF THE COCOS ISLANDS. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY DEPICTS PERSISTENT CONVECTION OVER THE NORTHERN PORTION OF A 
CONSOLIDATING, COMPACT LOW LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN A 
031440Z METOP-B ASCAT PASS. ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE 
CONDITIONS FOR DEVELOPMENT WITH LOW TO MODERATE (10-15 KTS) 
NORTHEASTERLY VERTICAL WIND SHEAR, WARM (28-29C) SEA SURFACE 
TEMPERATURES, AND FAVORABLE POLEWARD AND WESTWARD OUTFLOW ALOFT. GLOBAL 
DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD AGREEMENT THAT 91S WILL 
CONTINUE TO TRACK SOUTHEASTWARD AND STEADILY INTENSIFY OVER THE NEXT 24-
48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27 TO 32 
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 IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 
041800Z.//
NNNN