1:30 PM (Monday) | ***Buckle up…very active pattern continues for the next ten days with plenty of cold air around and multiple chances of accumulating snow and/or ice in the Mid-Atlantic region***

A “battle zone” in the atmosphere will form in coming days between deep (cold) upper-level low over northern US/southern Canada and a ridge of high (warm) pressure in the southeastern US. The Mid-Atlantic region will be right in the middle of this “battle zone” with multiple systems to deal with in coming days. Map courtesy NOAA, tropicaltidbits.com

Overview

It just won’t let up…a very active weather pattern will continue for much of the eastern half of the nation during the next ten days and there will be multiple chances of accumulating snow and/or ice in the Mid-Atlantic region.  Arctic air is in place as we begin the new work week across the northeastern quadrant of the nation and intense cold will grip the much of the northern and central US in coming days….in other words, there will be plenty of cold air around to tap into for the Mid-Atlantic region by approaching systems.

The first chance for snow and/or ice in the Mid-Atlantic region will come late tonight and tomorrow from a relatively weak system that moves into the northeastern states.  Despite its weakness, this initial system can cause some problems with accumulating snow north of the PA/MD border and potential ice south of there. A stronger system is likely to then impact the region in two waves during the second half of the week with one concentrating on the period from later Wednesday into early Thursday and then a second from later Thursday into Friday.  Accumulations of snow are certainly on the table in the DC-to-Philly-to-NYC corridor during this long-duration second half of the week event - and this won’t be the end of the wintry precipitation threats.  Yet another system could generate snow and/or ice in the Mid-Atlantic region later in the upcoming weekend and potentially more activity could come next week.

Intense and widespread cold will grip much of the northern and central US in coming days with temperatures at least 25 degrees below-normal for early February. Map courtesy WSI, Inc., NOAA

Discussion

Deep upper-level low pressure will be parked over the northern US/southern Canada during the next several days at the same time a ridge of high pressure tries to expand over the southeastern states.  In addition, a strong blocking pattern remains in pace over the northern part of Canada and Greenland and this has been playing a crucial role in our recent series of winter storms.  High pressure associated with the strong blocking pattern over northern Canada/Greenland is forcing cold air into the northern US and this cold will be intense cold in much of the northern and central US in coming days.  While the full brunt of the cold hasn’t made it into the Mid-Atlantic region, it is plenty cold as we being the week with Arctic air in place on top of a pretty good snow pack in most areas. 

The combination of the deep upper low across southern Canada/northern US and a burgeoning ridge of high pressure in the southeastern states is setting up a “battle zone” region in a west-to-east fashion across the mid-section of the nation and this active zone includes the Mid-Atlantic region.  Multiple waves of energy will flow across this “battle zone” region in coming days and each of these will present opportunities for snow and/or ice in the DC-to-Philly-to-NYC corridor.

Small amounts of accumulating snow are possible late tonight and on Tuesday in areas to the north of the Pennsylvania/Maryland border and there can be a break out of some light freezing rain in and around the DC metro region just before the AM commute. Map courtesy NOAA, tropicaltidbits.com

Threat #1 (Late tonight/Tuesday)

An upper-level disturbance just now reaching the Pacific Northwest will move quickly to the Central Plains by later today and then it should push into the northern/central Appalachians by early tomorrow.  Even though this system is rather weak, it has enough moisture to result in some accumulating snow on Tuesday in areas to the north of the PA/MD border region with 1-3 inches possible across the NYC metro region and a coating to an inch or so in southeastern PA.  Given the possible late night arrival time, there can be some issues for the Tuesday AM commute in the Philly and NYC metro regions.  Later in the day, sleet and/or rain can mix in at times and driving conditions should improve as temperatures head to well above the freezing mark.  

To the south of the PA/MD border, the precipitation from this weak system will be rather spotty light. Nonetheless, there can be problems for the morning commute in the DC metro region with the possibility that some light freezing rain breaks out towards daybreak with temperatures below the freezing mark. Temperatures will climb to well above freezing later tomorrow so there should be no issues for the Tuesday evening commute in and around the DC metro region. 

Accumulating snow and ice is on the table in the Mid-Atlantic region from later Wednesday into early Thursday and this threat (#2) will include the DC metro region. Map courtesy NOAA, tropicaltidbits.com

Threats #2 Later Wednesday into Thursday; Threat #3 Later Thursday into Friday

An extended period of precipitation is in store for the Mid-Atlantic region in the late Wednesday-to-Friday time frame that will tend to come in two waves.  The first wave (threat #2) of precipitation will be associated with warm air advection in the late Wednesday to early Thursday time frame and then a second wave (threat #3) will be associated with an upper-level trough in the later Thursday into Friday time period.  While sleet and/or freezing rain are likely to mix in at times in the Mid-Atlantic region during this extended second half of the week event, accumulating snow is definitely on the table including in the DC metro region which has had to struggle for its snowfall in the most recent two storms.  In fact, there is a chance for significant snow accumulations in the DC metro region from this Wednesday-to-Friday long-duration weather event.

Accumulating snow and ice is on the table in the Mid-Atlantic region from later Thursday into early Friday and this threat (#3) will include the DC metro region. Map courtesy NOAA, tropicaltidbits.com

Threat #4 (Weekend)

The weekend could feature a strong high pressure system over the Northern Plains with intense and widespread cold in the northern and central US extending from Montana-to-Michigan and Minnesota-to-Texas. There is also likely to be quite a bit of moisture gathering across the south-central and Gulf coastal states.  There are some signs that this moisture could push to the north and east later in the weekend and into the Mid-Atlantic region where there will be a cold air mass in place.  In other words, there is the chance for more weather problems in the Mid-Atlantic region later this weekend that can include snow and/or ice – perhaps just in time for Valentine’s Day (Sunday).  And – you guessed it – this weekend threat is quite likely not going to be the last in this on-going very active weather pattern.  

Buckle up…quite an interesting stretch of weather for the Mid-Atlantic region during the next ten days.

Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com

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