WTPN21 PGTW 280400
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 24.9N 150.0E TO 29.4N 143.0E
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 25 TO 30 KNOTS. METSAT
IMAGERY AT 280000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 24.8N 150.0E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 10
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 90W) PREVIOUSLY LOCATED NEAR 
24.1N 151.3E IS NOW LOCATED NEAR 24.7N 149.8E, APPROXIMATELY 461 NM 
EAST OF IWO TO. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A 
MORE CONSOLIDATED AREA OF CONVECTION WRAPPING INTO A MID-LEVEL 
ROTATION. HOWEVER, THIS SYSTEM IS VOID OF A LOW LEVEL CIRCULATION 
CENTER AND HAS A WEAK BUT TIGHT TROUGHING ASSOCIATED WITH A WAVE 
PROPAGATING NORTHWESTWARD. THIS TIGHT TROUGH IS EVIDENT ON THE 272330Z 
PARTIAL ASCAT-C PASS. ANALYSIS REVEALS A MARGINALLY FAVORABLE 
ENVIRONMENT FOR DEVELOPMENT WITH MODERATE EQUATORWARD DIVERGENCE ALOFT, 
LOW TO MODERATE (10-20KT) VERTICAL WIND SHEAR, AND WARM (30-31C) SEA 
SURFACE TEMPERATURES OFFSET BY A TUTT CELL TO THE WEST-NORTHWEST. 
GLOBAL MODELS PREDICT A MODEST INTENSIFICATION AS IT TRACKS NORTH-
NORTHWESTWARD OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 25 TO 30 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 IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 
290400Z.
//
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