A major storm complex is set to move out of the central Rockies and lift northeast for Christmas day and early Monday the 26th. This low is powerful, with tightly packed isobars, meaning ferocious winds along would be enough to make this system nasty. But, cold air and copious amounts of available moisture are set to make this into one of the more impressive blizzards in recent memory.
Blizzard conditions arise when winds mix with snow to knock visibilities down to 0 feet. It has nothing to do with intensity of the snow. In fact, the snow could be very light…but if the wind is blowing it hard enough that you cant see – Voila…Blizzard.
There are some blizzards, though, that do bring large amounts of snow. These become EPIC very quickly. We think this is one of those storms for SD, ND and northwest parts of MN. Moisture available to this system will be well over an inch – closer to 1.5″ if it were all rain. This will be a rather wet snow, but still, we feel confident that we can see easily 10-14 inches along and northwest of a line from Scottsbluff, NE through Fargo, ND. And, in these kinds of set ups, one can easily be amazed and surprised by an even heavier localized band of snow in there. Put these snow totals together with 20-40 mph sustained winds and some gusts up to 55 mph…and you have a recipe for complete shut down in parts of SD, ND, northern MN and even the Nebraska panhandle.
Timing on this system is mostly on Christmas day. Precipitation may start overnight Christmas Eve into Christmas early morning, but it will be light. The period of heaviest accumulation will be from Christmas afternoon through about 3 AM Monday. But…at this point, don’t get too excited one way or the other if is starts sooner or later and ends sooner or later. The key here is — stay home. Even for a region that is used to winds, snow and sometimes nasty winter events…this one will be pretty intense.