Complex Pattern for Monday Night Through Tuesday

I didn't post for the last couple of snowfalls because they were expected to be minor and turned out to be.  Just some snow showers on Thursday night into Friday morning and a few more on Saturday morning provided the dusting that the DC metro area received.

A much more complex situation is in the offing for a time period beginning Monday night through Tuesday night - possibly lingering a bit longer than that.  Much is still undetermined but there's a likelihood of accumulating snow here in the DC metro.  How much and where are both things that need a few more model runs to iron out.

As has become customary this winter, the models are all over the place and there's not much consensus beyond a good chance of snow on Tuesday.  This begins with a low pressure area forming in southeastern Texas and moving along the Gulf coast on Sunday night.  I expect this low to cross off the coast of the southeastern U.S. by Monday - probably around central Georgia.

From the north comes the polar jet and a disturbance rides along with it from the plains into the Ohio Valley.  This is expected to be pretty strong and it, alone, would likely produce some snowfall around here as it tracks across our region Monday night.

Here's where the models start to diverge.

Scenario 1, at this time the more likely, has the northern energy missing phase with the southern energy until the storm is well northeast of us.  This scenario means a weak coastal low, a more dominant inland low and light accumulation amounts depending on the strength of the inland disturbance and the proximity of the coastal low - weak as it might be - as it moves northeastward into the Atlantic.

Additionally, the models hint a secondary low forming in southwest Virginia and moving northeastward which would continue our snow chances through Tuesday afternoon and evening.

Even with the extended period of snow, it seems like a light event.

Scenario 2 would have the northern energy phasing with the southern energy which would strengthen the coastal storm and also having the effect of "holding" the storm closer to the coast as it moves northward.  This scenario is a classic nor'easter scenario - but, as in previous situations, the timing of the phase is everything here.

Right now the model consensus is for a later phase but when and where is very uncertain.

An early call would be a chance of snow Monday night with better chances Tuesday and Tuesday afternoon possibly extending through Tuesday night.  I can say that there's a good chance this will be "accumulating" snow which would mean, for me, "2 inches or more" but lots of details still have to be ironed out before we can have serious discussion about totals.

There's also the chance that storm track gives us mixing issues as temperatures will be borderline (low to mid 30's) during the balance of the day Tuesday.

I'll be watching the model runs pretty carefully for the next few days.  I'll start posting some maps in my next post.

Hopefully this one decides what it wants to do sometime before the day of the event!