On May 20 at 00:00 UTC, a potent extratropical cyclone formed in the mid Atlantic about 500 nmi (575 mi) east-southeast of Bermuda from a shortwave trough. The system started slowly moving in the Northeast direction during which, the northern half of the system started producing gale-force winds, thus creating an asymmetrical wind field. However, by the next day, the wind field had extended considerably reaching out about 330 nmi (380 mi) to the northeast.