WTPN21 PGTW 040700 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 94W)// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN A 135 NM RADIUS OF 16.9N 119.4E 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 17 TO 22 KNOTS. METSAT IMAGERY AT 040600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 16.9N 119.4E. THE SYSTEM IS MOVING WESTWARD AT 02 KNOTS. 2. REMARKS: THE AREA OF CONVECTION (INVEST 94W) PREVIOUSLY LOCATED NEAR 17.7N 121.8E IS NOW LOCATED NEAR 16.9N 119.4E, APPROXIMATELY 63 NM SOUTHWEST OF VIGAN. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN OBSCURED NASCENT LOW LEVEL CIRCULATION CENTER (LLCC) ALONG THE WESTERN COASTLINE OF LUZON THAT FEATURES CONVECTIVE BANDING ALONG THE SOUTH-WESTERN PERIPHERY OF THE CIRCULATION. STRONG WEST- SOUTHWESTERLY FLOW IS CLEARLY SEEN FLOWING INTO WESTERN LUZON, ROUGHLY FROM LINGAYEN GULF SOUTHWARDS. ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE CONDITIONS FOR TROPICAL CYCLONE DEVELOPMENT, AS THE SYSTEM IS POSITIONED WITHIN A POCKET OF LOW VERTICAL WIND SHEAR (10-15KTS), WARM SEA SURFACE (29 TO 30 C), AND GOOD EQUATORWARD OUTFLOW. GFS IS THE ONLY DETERMINISTIC MODEL CURRENTLY DEPICTING CONSOLIDATION OF 94W IN THE NEXT 24 HOURS, SHOWING THE WESTERLY WINDS SOUTH OF LINGAYEN GULF QUICKLY TURNING NORTHWARD DUE TO TERRAIN FORCING, AND WRAPPING INTO THE QUICKLY DEVELOPING CENTER. MEANWHILE, THE ECMWF KEEPS THE CENTER CLOSER TO SHORE AND DOES NOT CONSOLIDATE THE CIRCULATION OR WRAP THE SOUTHERLY WINDS UP THE EAST SIDE DUE TO THE PROXIMITY TO LAND. ENSEMBLE MODELS BOTH AGREE ON THE FURTHER DEVELOPMENT INTO A TROPICAL DEPRESSION AND A GENERAL EASTWARD TRACK BACK OVER LUZON AFTER 24-36 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 17 TO 22 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 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 050700Z.// NNNN