I have spent time researching what I would get but options are somewhat limited due to unique tire size: 255/55/20.
Excluding the more snow rated tires my options are:
Michelin
Defender2 (just put these on my MKZ)
Primacy A/S but seem these are being discontinued
Pirelli
Scorpion WeatherActive
Scorpion AS Plus 3
Goodyear
Assurance WeatherReady - discontinued with no similar
No Continentals in that size.
Hi angore. You do not mention where you checked for tires. However, check The Tire Rack. They show ~41 available tires in that size from:
BFGoodrich (1), Bridgestone (1), Cooper (3), Falken (3), Goodyear (3), Hankook (2), Kumho (1), Laufenn (1), Michelin (6), Nitto (2), Pirelli (9),
Sumitomo (1), Toyo (1), Vredestein (4), Yokohama (3).
Only one of those tires is rated strictly as a "snow tire". A few do have a "Severe Snow" rating, but they are still All-Season tires. The rest are rated "All-Season", "Touring", "All-Terrain", "Summer" etc. Essentially, most are "Crossover/SUV Touring All Season" tires.
And to my knowledge, the Michelin Primacy is not being discontinued. Perhaps the newer/updated version is being released soon, so the "older" version may be on clearance, and/or listed as limited availability/stock. This is standard procedure.
I realize a lot of these brands may not be on your preferred shopping list, but you do have more than 5-6 choices. Michelin and Pirelli alone offer ~15.
Hope this informaton helps and good luck.