We have the first truly wild setup coming up in the coming days and after a system brought 4-8 inches of snow to the mountains surrounding both Anchorage and Fairbanks over the past few days, that same storm system is set to drive into southern British Columbia and Washington.

Cold air is attached to this system and will sent the first real deep trough into the western US. As your well aware, heavy snowfall is expected in the mountains and it could be as low as 5,000ft in western Montana, south, southeast Idaho and Wyoming.

Exactly how much?

Here’s the GFS snow forecast through the next 72 hours.

Yes some areas could pick up 2 feet or 24 inches of snow and I suspect a few records will fall with this event.

Check out the wild amplification Friday with the deep trough driving cold air into the system which this pumps a strong ridge well into Canada!

Big temperature contrast sets up between the Northern Rockies where temperatures Friday afternoon are unlikely to exceed the mid-30s in areas where snow is falling heavily while at the same time, SSW winds blow, 850 temps are warm and with the help of some sunshine, we could see mid-80s from St Louis to Chicago. Will depend upon strength and exact direction of wind but bare in mind that the ground is rather dried out and this should help warm things up.

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While a lot of interest out West will on the first big snows coming, Easterners are keeping a close eye on the models as some sort of hybrid storm system looks set to develop and become fairly intense of the East Coast late weekend into early and mid next week.

Still a little far out yet and without anything actually developed yet, it’s hard to know how strong or exactly how close to the coast any storm could get.

Firstly I want to show you the blocking set up indicative of the -NAO

Here’s where we’re at with the NAO

Here’s the strong blocking over Hudson Bay with a big upper low over Newfoundland according to the CFSv2 (using this because it shows up well.

Here’s the ECMWF by next Monday

Note the blocking HIGH not upper low over Newfoundland by then.

Now, the area of convection now crossing Florida may be, in my opinion the feature that modelling is trying to develop and this thing appears to drifts northeastwards off the coast but bare in mind that it’s crossing 80-85 degree waters off the Carolinas but there is no reason why this thing cannot wind up, probably as a mix of tropical and baroclinic and not fully warm core.

Now, it’s as this system drifts northeast, the big high looks set to build east over Canada out into the Atlantic and so this gets caught and with winds blowing ENE under the high, then this thing could get pulled towards the Northeast. Some models show this closer to the Mid-Atlantic coast in the first place.

Here’s the ECMWF’s take on this.

36 hrs

72 hrs

120 hrs

Mon

The Canadian has a deeper system but it’s further east.

144 hrs

It’s still way to early to say what and where and I also want to point out, this is NO SANDY! Very different situation.

Stay tuned…

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Tags: East Coast storm? East Coast storm threat, Rockies Snow