If you haven't seen this video yet, give it a look. This is a time-lapse video of the snowfall near Hartford, CT.
When you consider NYC even got in on the action at 8-12 inches, why didn't we see any snow here? It sleeted/snowed for about an hour on Thursday night and then rained a bit into Friday morning.
Boring!
Let's have a look at what happened because this has bearing on the upcoming possibilities. To save you from sensationalistic plugs that make you read an entire post before you get what you're looking for, I present a digest:
3 chances in the next 7-10 days:
- Wednesday 2/13
- This coming weekend
- Next Monday-Tuesday or so
Those of you with short attention spans can now go merrily on your - LOOK! SOMETHING SHINY!
Onward...
It's all about storm type and phasing. There were two systems moving eastward in the two main branches of the jet stream. The Northern Stream storm would head on a path across the Upper Midwest and to the north of our area.
Since winds move counterclockwise around a low pressure system, this created a southerly flow around our area that quickly changed frozen precipitation to liquid overnight on Thursday.
This was a Miller B type storm (as they all have been this year) and as the Northern Stream system moved eastward it transferred its energy and phased with the Southern Stream system which had moved out of the southeastern US and up the Atlantic Coast.
Now, storms moving along the coast from the south in the winter is usually a good thing for us. However, with that Northern Branch system moving north of us and the phase happening just to our northeast, we were caught in the middle - in an area between two phasing low pressure systems. This is almost always a zone of minimum precipitation and it's a big problem with Miller B storms that don't phase to our south.
The Southern Stream storm would move from the southeast and then up the coast, phasing with the Northern Stream late in the afternoon on Friday - well to our northeast. The precipitation gradient was extreme with parts of the Eastern Shore seeing heavy rain all day Friday while we in DC saw some sunshine in the afternoon.
Here are the two storms last Thursday morning as they began to phase.
Watch the following animation and see the phase as the southern system absorbs the northern system.
Notice a couple of things here. First, the northern storm starts to weaken (the 1008 mb contour disappears from the center of that storm towards the end) and the storm on the coast significantly intensifies as it moves up the coast (the last few frames show a center contour of 996 mb). Where are we?
Right in the middle.
Ok - congratulations to our friends up north. What about our snow? Let's talk about the first chance.
WEDNESDAY 2/13 - THURSDAY 2/14
The models have been showing a "Valentine's Day Storm" for a while now and it's encouraging that this close to the event, they still have it.
What's discouraging is that they seem to have little consensus about what path its going to take and whether temperatures in our area will be suitable for frozen precipitation.
At the moment, I would classify the event as marginal as we're in one of those situations where a more northern track would produce heavier precipitation but also warmer temperatures (rain) and a southern track would produce lighter precipitation but colder temperatures (snow). In this case (ironically), the best place for us to be would be in the middle of those track solutions.
Here's the Euro at hour 72 (Wednesday night) showing the storm center in the southeastern US:
And then off the coast by hour 96 (Thursday morning)
which, as you can see, would move the higher axis of snow accumulations northward.
This bears watching and until there's a track consensus, anything is possible from warning-criteria snow to a rain event here.
We'll see what the evening model runs hold.
I'll post later about snow chances on the weekend and then a bigger chance early next week.
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