18z Canadian (RGEM) Model Shows One Hell of a Nor’easter

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If you average all the models and take into account the record spring-like temperatures of late we wind up with rain going over to a period of heavy wet snow with accumulations mainly being confined to grassy surfaces.  If the European and Canadian models are accurate with colder air rushing in faster and this storm deepening (or slowing down at all)… we have a very interesting forecast on our hands pre-dawn Thursday for portions of our region.  Folks from the northern Shenandoah Valley to Baltimore northeastward to Philadelphia, the Jersey Shore and Cape Cod are currently looking at their first major winter storm of the season. Yes some of the snow will definitely melt as it falls due to the warm conditions but the probability may begin increasing of 4″ or more in these locations and will need to be closely monitored.  

This leaves the Washington Area in the usual conundrum of details that still need to be worked out. You know the saying, “The Devil is always in the Details”.  I remember a February storm that rolled through the DC Area dropping over a half-foot of snow after high temperatures were in the mid to upper 60s.  There are dynamics in the atmosphere that can produce incredible snowfall rates that overcome antecedent warm conditions wreaking havoc on unsuspecting commuters.  Right now, the area that will be most susceptible to potential slush/snow-covered roadways are those of you across northwestern Virginia into the Baltimore Metro Area.

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Saturday Update on Clipper and Snowfall Accumulation Potential

Happy Saturday to all! I have to say that I this winter so far feels like “Pittsburgh” minus the snow.  I don’t remember so many cloudy days in recent winters and I would like some snow pack and sunshine which brightens everything up.  Well those of us who want snow (it is winter after all) may have a lot to look forward to this week and into next weekend. I will address next weekend’s potential storm in another post, so let’s take a look at potential impacts to our “wonderful” Washington Area rush hour on Monday morning.

This morning’s latest (12z/7AM EST) high-resolution North American Model (NAM) is currently depicting an area of light to moderate snow impacting parts of the Washington Area between midnight and 5AM on Monday.  

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Where exactly this “area” of snow sets up is still in question according to the ensembles.  From what I am seeing, locations that are lucky enough to be under this area of light to moderate snow will probably pick up enough to whiten the ugly, barren, ground and if some enhanced lift occurs, don’t be surprised if some of us end up with up to an inch of snow.

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Next Blast of Arctic Air & Watching the Coast Midweek

Next Shot of Arctic Air Arrives Monday Afternoon

Next arctic front arrives Monday afternoon and the cold weather will last through much of the work week.

After a brief moderation in temperatures this weekend, the next arctic front will blast through the DC Region on Monday afternoon ushering in below zero wind chills and highs once again struggling to get out of the teens and low temperatures near zero.  The cold air will begin to moderate through the later portion of the work week but temperatures will still remain slightly below normal through the upcoming Super Bowl weekend.

Here are the latest Preliminary Snowfall totals so far this winter at the three major Washington Region Airports:

Reagan National Airport (DCA):  7.2″

Washington Dulles Int. Airport (IAD):  16.5″

Baltimore – Washington Int. Airport (BWI):  12.2″

Watching the Southeast Coastline on Wednesday:

GFS Ensembles agree that a storm system will develop off of the Carolina coastline on Tuesday & Wednesday.

GFS Ensembles agree that a storm system will develop off of the Carolina coastline on Tuesday.

I am interested in a developing area of low pressure off of the southeast coastline on Tuesday and Wednesday of the upcoming work week.  Earlier runs of the European Forecast Model hinted that the track of this system may come close enough to the coast to possibly affect the Mid-Atlantic.  **I was honestly quite alarmed at the lack of warning we had on the models with the last snow event as we really only had about 36 hours of warning before it struck.**

GFS Ensembles

GFS Ensembles show 15 different placements of an area of low pressure (red numbers off of the North Carolina coastline) during the same time frame during the middle portion of the upcoming work week.

Bottom Line:  This coastal storm may produce snow in the Carolinas and then move out to sea without any fanfare across the Washington Area.  Or, this system may end up tracking closer to the coast producing accumulating snow across our area.  Due to the lack of warning with the last system, I will be closely watching the forecast models for any signs of a shift in track to the west.