Heavy Rain Sunday and Monday will Relieve the Moderate Drought Conditions but what about Snow?

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The interstate 95 corridor is still experiencing moderate drought conditions after what was a very dry Autumn. Regardless of the eventual track of our next storm, it’s likely to produce several rounds of heavy rainfall across the metropolitan area Sunday afternoon and again on Monday.

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How much rainfall could fall?

The latest European forecast model (image below) shows that a widespread one to three inches is likely by the time the storm pulls away from our region Monday evening into Tuesday afternoon.

Locations along and east of the blue ridge could easily pick upwards of 4″ of rainfall aided by orographic lift (easterly winds rising up the eastern slopes of the Blue Ridge mountains). 

ecmwf_tprecip_washdc_21-1

GFS Ensembles also show significant rainfall across our area:

gefs_qpf_ens_washdc_20

Latest storm track “trend runs” of the GFS (first image) and GEM (Canadian, image two, both courtesy TropicalTidbits.com):

  • Latest runs have shifted back to more of an inland track.  This could still change… hopefully. 

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This morning’s latest forecast guidance suggest that the boundary layer temperatures between 700 and 850 mb (~10k to ~5k feet above the surface) will likely remain above freezing, meaning as of now, without a change in track further offshore, rain is the likely outcome.

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Ensembles from the Euro and GFS still show the potential for snow to fall across interior sections of the northern Mid-Atlantic states (Pennsylvania and New York) as well as interior New England.

Latest GFS Ensemble (Courtesy Weatherbell.com):

First image shows the control run (eC), following individual ensembles one through twenty (e1 through e20) and finally the mean (eM).

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European Ensemble Mean:

  • As the storm pulls away and colder air moves in behind it, fresh snow is likely along the western slopes of the Appalachians (Garrett County, MD, Snowshoe WV).

eps_snow_m_ma_21

Medium Range thoughts on the Mid-Atlantic Snow Drought:

Winter so far has had both bitter cold periods and mild periods. We have not been fortunate to link up moisture with the cold.

The NAO has stubbornly been mostly neutral to positive.

As colder air moves into the eastern United States late January into February, the current NAO forecast is trending positive meaning that the pattern would favor fast moving clippers versus Nor’easters.  The “broken record” of cold air without high latitude blocking continues to burn a hole in the stomach of those of us who would do anything to buy a decent snowfall across the Washington Region.  Do I think we will get a storm this year? Yes, eventually.

February is our snowiest month on average.  Will we see a blizzard? As I stated in my winter forecast I have not seen two consecutive winters with a blizzard producing the 18 to 30″ amounts in one storm.

One thought on “Heavy Rain Sunday and Monday will Relieve the Moderate Drought Conditions but what about Snow?

  1. Andy

    It looks like the last large chart is at least holding out hope for an inch or two of wet snow at the end. Any more than that would be a long shot, as you have stated, with the inland storm track and the warm ground.

    A general 18-30″ snowstorm in DC is historically quite a rare event. Between 1900 and 1979, there was only one storm that “officially” produced over 15″ for DC, the famous “Knickerbocker Storm” of 1922. I am only aware of 3 such storms in the 1800’s (1821, 1857 and 1899). So until recently, a storm of that magnitude was basically a one in fifty year event.

    But in the 38 years since 1979, there has been 7 storms over 15″, even at the “snow black hole” known as National Airport, with 20″+ amounts at the suburban airports. So as snow lovers, we have truly been blessed to have lived when we did!

    The records show that all the major cities from DC to Boston have played way over their head since the late 1970’s. A result of global warming? Does not appear logical on the face of it, but that is what some are claiming.

    Like

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