GTC Polar front

Polar front--- I'm sure anyone from temperate region (e.g. me) know the effect of this front: The temperature drops 20-30C within 12 hours. (Manitoba is famous of its cold winter + continental climate, and it seems this front would be less effective in Europe, but that's not the case of this city) Drops 20C within 12 hours! Guess! A rare shot! Hint: Elevation > 400m but < 2,000 m >