Basically, we're looking at a huge, disastrous blizzard, concentrated mostly around the area north of Seafoam. Hardest-hit cities are looking to be Fuchsia, Vermillion, Lavender, Saffron, Celadon, and Viridian. Heavy snows will also be falling in the rest of Kanto and eastern Johto; cities west of Goldenrod will get something of a wintery blast as well, but will be nowhere near approaching the emergency situation the other cities may be dealing with. Snow will continue falling until late tomorrow or the 15th, in droves.
Articuno will be visible in the skies tonight and tomorrow during the snowfall over the cities in the order roughly outlined above for any careful watchers, but won't get close enough to the ground to be captured, obviously.
Keep in mind it doesn't really snow all that much in Kanto and Johto to begin with, and people are unlikely to be prepared for it; for those nearest the epicentre, imagine the chaos if southern California was suddenly hit with three or four feet of snow, and run with that. :3