Spring to Start; Cold Returns by End of the Week..and Snow?

10/26 3am

We will continue our upward climb in temperatures Sunday with highs getting up into the mid-60s with lots of sunshine thanks to high pressure working directly over the area.  Clear skies and calm winds will allow temperatures to quickly drop into the mid-30s Sunday night.  A few areas of patchy frost will be possible across the more sheltered valleys.  Southerly flow due to clockwise flow as high pressure works off the coast will help highs quickly rebound during the day Monday.  It looks like we may crack 70 both Monday and Tuesday and it wouldn't surprise me if Tuesday is more like 75+.  

Temperature roller coaster ride this week. KCHO-Charlottesville. Image via Iowa State

Just as we're getting used to this warmer weather, a significant trough looks like it'll dive across the eastern US by the end of next week.  There's already been quite a bit of buzz concerning whether this will bring the first widespread snow accumulation potential across the mid-Atlantic.  Besides the fact it's over 5 days away, it's really only been the past few runs of the European model that have had such an extreme solution.  To get accumulating snow this far south this time of year, you really need northern stream energy to dig deep into the Carolinas, providing a sufficient combination of precipitation and cold air.  Although the past few runs of the European have shown this, both the European ensemble means and GFS (the American model) aren't nearly as sharp or deep with the digging energy (image below).  What this does is causes the storm to develop over the northeast as opposed to popping it over the VA/NC coast.  This would give parts of interior New England their first substantial snow of the season, leaving us with a few upslope western mountain snow showers as northwest winds crank in behind it.  With a progressive pattern keeping flow pretty quick across North America currently, that's where I'm leaning. 

Euro vs GFS 500mb Maps for Late Week.  Images via AccuPro

Bottom Line: Expect quite the roller coaster ride in temperatures this week.  The first half of the week will be very warm, while the end of the week is back below average.  Still lots of time to work out the impacts from the late-week storm.