Saturday, March 3, 2012

Winter's Last Stand

After the last Virginian snow-storm on the February 18-19 weekend, many declared winter over.  In a way, it's hard to blame them.  Temperatures reached well into the 60s and 70s over much of Virginia.  We have had two storms produce strong storms for much of Virginia.  In another way, come on, this is Virginia.  This is how the weather typically behaves in March as we experience a battle of spring vs winter causing a roller coaster like no-other.  I didn't bite into that nonsense that snow was over for Virginia.  I'm now ruling the two events at the end of this weekend winter's last stand.  I may look back in a few weeks and realize that I too jumped the gun on declaring winter over, although not as soon as some.  Come on its March.  These things happen every year.  We have a significant warmup, rain, sunshine, snow.  Last Sunday I posted about the chance of a coastal low forming along the trailing old front of a Great Lakes' Cutter as our best possibility of seeing snow this time of year.  Well we had our Great Lakes' Cutter which brought rain to all of the area last night into this morning.  The trailing cold front remains stretched out over the southeast at this time, setting the stage for the first of the possible two snow-producing events late this weekend.
Here's the current radar from Saturday 1230PM.  To our north is the Great Lakes' Cutter.  We will have to watch for an area of low pressure (circled in red) to form along and ride the trailing cold front.  I'm going to post each of the 12z model runs to show you an idea of what may happen.

12z GFS:

12z NAM:

12z UKMET:


The CMC is definitely the warmest of the 4 models I showed.  I think there will be some wet snow mixed in with the northern fringe of this system.  Here is where I think the best chance for some rain/snow mix will be.  The question mark is concerning just how far north and west the precipitation can get.  If it can get just 25-50 miles farther west of where models have it now (gfs is closest), then there could be a bit more of a snowier northern fringe.  I still don't expect much by the way of accumulation.  Our attention will then turn to a clipper swinging through the area Sunday night.  This will have much colder air to work with, and will be coming during prime time night hours.  The first model I'm going to show is the 12z nam, which is the farthest south and weakest of the models.

12z Nam:
 As you can see, this ends up just being a few light snow showers/flurries and not a big deal for anyone.  The 12z gfs shown below is a bit farther north and a bit stronger with the clipper.

12z gfs:

12z UKMET (strongest of the 4 models):

and the 12z CMC (farthest north/warmest):

So it does look like the second system, the clipper, will bring snow to Virginia.  I believe that the clipper will lay down 1-2 inches in its sweet spot, which is typically just north of where the actual low tracks.  If the UKMET were to verify, I could even see a higher elevation getting as much as 3".  I'm not going to post a snow map for this second system yet due to the uncertainty there is in both the exact track and strength of the clipper.  I've also seen countless times where clippers hit the mountains, die for areas just east of the mountains, and then redevelop precipitation over central/eastern areas of Virginia.  The stronger the clipper, the less affect this has.  Although both small, having back to back opportunities for snow after many ruled winter over will be fun, especially after the lack of a winter we've had so far.  Snow map for the clipper will likely be issued late tonight/early Sunday morning. -HV


  1. Nice analysis. I took a peek at the 00z NAM and GFS runs. In the mtns near Front Royal, looks to me like the first event will miss but maybe some light snow from the clipper... thoughts?

  2. thanks. flurries <1" looks like it should stay to your south for the most part