WSCN04 CWAO 271221
CZYZ SIGMET F4 VALID 271220/271620 CWUL-
CZYZ TORONTO FIR FRQ TS OBS WI N4722 W08304 - N4758 W08440 - N4837 W08345 -
N4807 W08146 - N4722 W08304 TOP FL440 MOV ENE 20KT WKN=