Upfronts
From Super-wiki
The Network Upfronts are held each May, in the last week of sweeps week. Each network has a separate session in which to promote its programming for the next year, and showcase new shows. Over recent years, many renewal, cancellation or pickup announcements will be made earlier.
2005
Supernatural was announced as part of The WB Fall Schedule, to air on Tuesdays after "Gilmore Girls".