Wednesday Snowfall Potential & My Opinions on How DC Handles Winter Weather

This is a tricky forecast.  Last Tuesday wasn’t a tricky forecast … I predicted one to three inches of snow and some folks got 4″.  The media downplayed the clipper with Washington media outlets forecasting a dusting in D.C.  The National Weather Service did a good job of warning of one to three inches of snow and issued a Winter Weather Advisory warning of travel difficulties due to the cold temperatures.

Fast forward to tonight:  This is a very tricky forecast because for one we are dealing with cold temperatures again, so every snow flake and sleet pellet that may fall would stick.  The problem tonight is that most of the forecast models keep the snowfall south and east of D.C.

Then there is the outlier model… the North American Model (NAM)… which is forecasting some light snow making it into the Washington Area.  So the National Weather Service issues a Winter Weather Advisory because of the 1″ rule during rush hour.  Will up to 1″ fall in the immediate D.C. Area? Honestly, it depends which model you look at.  The SREF and NAM have at least a 50% probability of a trace to one inch accumulating but the GFS and some of the higher resolution short-term models keep anything appreciable well south and east of DC (Fredericksburg over to southern Maryland).

Models:

Here is the GFS model which keeps accumulating snow just east of interstate 95

NAM model - Light Snow makes it as far west as foothills of the Blue Ridge at XX AM.

GFS model – Light Snow makes it as far west as foothills of the Blue Ridge at 7 AM.

Here is the HRRR (High Resolution Rapid Refresh) model which keeps snow across south-central Virginia and the Tidewater.

hrrr_current_east_06AM

Rapid Refresh Model - Accumulating Snow remains across south central VA and the Tidewater.

Rapid Refresh Model – Accumulating Snow remains across south central VA and the Tidewater.

Here is the North American Model (NAM): Accumulating/falling snow makes it into the Washington Metropolitan Area

namconus_ref_frzn_neus_5

NAM model – Light Snow makes it into Northern VA and DC at 4AM

 

NAM model - Light Snow makes it as far west as foothills of the Blue Ridge at XX AM.

NAM model – Light Snow makes it as far west as foothills of the Blue Ridge at 7 AM.

NAM model - Light Snow makes it as far west as foothills of the Blue Ridge at XX AM.

NAM model – Light Snow falls in the immediate D.C. Area at 10 AM.

NAM model - Light Snow makes it as far west as foothills of the Blue Ridge at XX AM.

NAM model – Light Snow and Sleet tapers off in the D.C. Area (1 PM)

Confidence is moderate for some light snow or flurries to fall from north-central Virginia (Fredericksburg) across to southern Maryland with up to one inch falling.

However, confidence is very low that some light snow will make it into Northern Virginia, D.C. and central Maryland.

Last Tuesday could have been averted if OPM had issued a delayed opening until 11AM with the option for Unscheduled Leave.  The folks at the National Weather Service become the media’s scape goat.  NOAA issued a Winter Weather Advisory for 1 to 3″ warning of snow-covered roads but the media downplayed it with “a dusting” falling in the District.   Understandably, we are now left in a heightened state of caution. In the past, Fairfax County would have closed schools with one to three inches covering our hilly terrain with temperatures in the lower to middle 20s.  They were warned of this from NOAA… who were they listening to? Probably the local media outlets.

Bottom line: this is a very low confidence forecast.  We may wake up to clouds with a few scattered flurries in DC… or we may find out that the NAM model is correct and some light snow makes it into the immediate D.C. Area with up to one inch falling. We shall see…

Low Confidence Best Guess Forecast taking a blend of the models

Low Confidence Best Guess Forecast taking a blend of the models

D.C. is often the butt of jokes for how we handle snow. However what the folks who mock us don’t understand is we live in a metropolitan Area of sprawl with 8 million folks commuting long distances with very few interstate arteries (interstates that can’t even handle the volume of traffic during a dry, sunny, rush hour).What’s comical is our area if chock full of Yankee transplants who are unable to drive in D.C. conditions because they can’t even move on our clogged interstates during winter weather.  The District of Columbia and Baltimore are due west of southern New Jersey.  On average we receive more snowfall across the vineyards of Northern Virginia (around Dulles airport) than Cape May New Jersey.  We are closer to New York than we are to Raleigh.  We are at the southern end of the Northeast Megalopolis.. ever heard the term “BOS-WASH”? Google it.  This isn’t the Deep South. Our problems are not due to our location… it’s the highly concentrated population and lack of infrastructure. Pile on traffic during a light snowfall with temperatures in the lower 20s… and plows are also sitting in traffic. It’s a recipe for disaster.

I’m not very excited about our snow prospects in the immediate DC Area tomorrow… mainly because most models keep accumulation well south and east of the city. But if the NAM and SREF models are more accurate … then with an abundance of caution due to calamities caused by previous bad decisions… it’s better to be safe than sorry… hence the National Weather Service issues a Winter Weather Advisory for the potential of up to 1″ falling during rush hour.  If we wake up to clouds and two flurries falling with zero issues… I’m sure people will want to blame the National Weather Service.  The folks at NOAA do a great job. Cut them some slack… it’s the politics of Weather Forecasting in this town & bad infrastructure (urban sprawl with few arteries for travel) that cause most of our travel nightmares during winter.

4 thoughts on “Wednesday Snowfall Potential & My Opinions on How DC Handles Winter Weather

  1. Andy

    I hope you don’t mind other opinions on your blog, but will just throw out my 2 cents worth for whatever it is worth. One model that is a bit more bullish is the Canadian. That has the snow line all the way out to western Maryland and West Virginia.

    When the models are conflicted, I try to look for hints. One hint that I believe is bullish is that there is a long easterly fetch at low levels coming in from way off the Atlantic, the orientation of the high north of us is very favorable. Also there is just enough of a kink in the upper air to support some development.

    At the considerable risk of making an idiot of myself, I would say that snowfall amounts will be comparable to last week, with the heaviest amounts in the eastern suburbs.

    Like

    • Tim

      I hope you are right! And as for your thoughts on the upcoming weekend.. it is MLK weekend… traditionally a snowy time here heading through President’s Day. The GFS is hinting at a possible coastal. I hope we get slammed late this weekend. Would be nice to get a 15″ + storm around here. Thanks for your opinions… always appreciated. Again I hope that we can squeeze out some qpf and that the SREF/NAM/Canadian are onto something.

      Like

  2. Andy

    Well, we squezed about .1″ out of it! Around 4-5 AM, the radar looked promising, then it fell apart. You did an excellent job with one of the more difficult situations we have had recently.

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s