*****Accumulating snow in the Mid-Atlantic region on Sunday at front end of an Arctic invasion…several inches on the table I-95 corridor…brutal cold to follow with zero degrees a possibility*****

Temperatures will be around 5 below zero (degrees C) at mid-day on Sunday in the DC-to-Philly-to-NYC corridor likely resulting in an all snow event. If by small chance there is rain at the onset then it would likely changeover quickly to accumulating snow. Map courtesy ECMWF, Weather Bell Analytics

Overview

The next several days will feature the worst that winter has to offer across the nation with widespread brutal cold and multiple snow and ice threats. An Arctic invasion with a Siberian connection will get underway by Saturday as bitter cold air from Canada plunges southward through the central states. By Sunday, the Arctic air mass will spread eastward towards the Atlantic seaboard and by the time we get to Monday, Inauguration Day, most of the country will be in a deep freeze including the DC metro where outdoor activities are planned for the swearing-in ceremonies. In fact, the first couple of days of next week could be among the coldest seen across the nation in a long, long time as there will be bitter cold conditions extending virtually from coast-to-coast.

This cold weather pattern will come with as many as three threats of snow and ice during the next week to ten days. On Sunday, low pressure will form along the incoming Arctic frontal boundary zone and likely produce several inches of snow across the Mid-Atlantic region and Northeast US - and this includes in the big cities along the I-95 corridor. Another storm is destined to form over the Gulf region by mid-week and its focus could be on the southern states with significant snow and ice a possibility down there. Yet another system can again develop way down in the southern states by the end of the next week or during the subsequent weekend.

Temperatures will be “crashing” at the 850 mb level later in the day on Sunday as Arctic air advances. This incoming air mass is fully supported of snow in most areas of the Mid-Atlantic and NE US. Map courtesy ECMWF, Weather Bell Analytics

The Arctic blast (with a Siberian connection)

The colder-than-normal weather pattern that began earlier this month across the central and eastern US not only looks like it will be extend through the third week of January, but it is going to go to more extreme levels. The outbreak of Arctic air will get underway by early Saturday over the north-central states and the bitter cold air mass will plunge southward all the way into the heart of Texas by late Saturday and then it spreads eastward on Sunday.

Temperatures will fall to well below-normal levels across much of the nation for the first half of next week which is quite impressive indeed considering this is right around the time of year with the lowest “normal” temperatures. In fact, a huge chunk of the Northern US will see their temperatures drop to well below zero by early next week. The first couple of days of next week could turn out to be the coldest in a long, long across the nation with the brutal cold extending virtually from coast-to-coast. The upper-level pattern across North America has evolved into one that is producing “cross-polar” flow allowing for Siberian air to cross the North Pole and drop into Canada and the US. Siberia is land mass known for its extremely cold air masses this time of year as it typically features a very deep snowpack.

A snowstorm looks likely for Sunday and Sunday night across much of the Mid-Atlantic region and Northeast US. This will come at the front end of an Arctic air outbreak that can bring temperatures down to near or even below zero early next week in this part of the nation. Map courtesy NOAA, tropicaltidbits.com

Sunday snowstorm in the Mid-Atlantic/Northeast US

On Sunday, the Arctic front at the leading edge of the Arctic air mass will slide into the eastern states and its progression will likely slow down across the southeastern states. Energy will rotate through an upper-level trough on Sunday, and this will open the door for an Arctic wave of low pressure to form along the front’s temperature gradient zone which is typically a favorable area for convergence in the atmosphere. That low pressure system will likely then push northeastward into an increasingly colder air mass, and it can produce snow or perhaps rain that quickly changes to snow in the Mid-Atlantic region by from Sunday into Sunday night. Accumulations are most certainly on the table all along the DC-to-Philly-to-NYC corridor with preliminary snowfall estimates as follows:

DC:     3-6 inches with isolated higher amounts (mid-morning starting time)

Philly: 4-8 inches with isolated higher amounts (mid-day starting time)

(This weather will make for quite an interesting Eagles-Rams game at 3pm on Sunday in South Philly).

NYC:   4-8 inches with isolated higher amounts (mid-afternoon starting time)

All areas in red on this particular map have a 90-100% chance of seeing temperatures at or below zero by the middle of next week (output from the Euro Ensemble model). Map courtesy ECMWF, Weather Bell Analytics

Inauguration Day (Monday) weather…a frigid DC with a fresh snow cover

By Monday, January 20th, the bitter cold air will be firmly established across much of the nation, and this includes in the DC metro region where outdoor activities are currently still planned for the Inauguration Day ceremonies. Temperatures are likely to be not far from 20 degrees at noontime on Monday in the DC metro area - the coldest Inauguration Day since 1985 (more info below) - and there will be a biting wind to make it feel even colder than the actual air temperatures. In addition, there is likely to be a fresh snow cover in the DC metro region on Monday following what I expect to be accumulating snow to precede on Sunday. Temperatures on Monday night (and also Tuesday night) should easily drop into single digits along the DC-to-Philly-to-NYC corridor and could bottom out near zero degrees with the expectation that there will be a fresh snow cover (usually knocks off a few degrees).

The most recent Inauguration Day that was impacted considerably by the weather took place in January of 1985 for Ronald Reagan’s second term. It was so cold on that day in Washington, D.C. with an Arctic outbreak into the eastern states that all outdoor activities were cancelled. The outside temperature at noon on January 20th was only 7°F and wind chills during the afternoon were in the -10 to -20°F range. That particular cold wave in January 1985 happened to follow a major stratospheric warming event that got underway during December of 1984.

It was so cold on January 20th, 1985 that all outdoor activities for Ronald Reagan’s second swearing-in ceremony were cancelled. Temperatures were in single digits at the noon swearing-in time in Washington, D.C. on January 20th during what was an extremely cold Arctic air outbreak. Map courtesy NOAA

On the eve of JFK’s inauguration in 1961, eight inches of snow fell on Washington, D.C. causing the most crippling traffic jam the District had ever seen up to that point of time with hundreds of cars abandoned on the local roadways. By sunrise on the 20th, the snow had ended, and the skies were clearing, but the day remained bitterly cold.  An army of men worked all night to clear Pennsylvania Avenue and despite the cold, a large crowd turned out for the swearing-in ceremony and inaugural parade. At noon, the temperature was only 22°F and the wind was blowing from the northwest at 19 mph making it feel like 7°F above zero. (For some excellent information on “Inauguration Day weather” visit this NWS site).

This snowfall forecast map by the middle of next week depicts accumulating snow across both the Mid-Atlantic region and Northeast US (Sunday/Sunday night system) and also across the southern states from Texas to the Carolinas (mid-week threat). Map courtesy NOAA, Weather Bell Analytics

Mid-week and late week storm threats

It’ll remain brutally cold on Tuesday and Wednesday across much of the nation (below-freezing temperatures all the way down to the Gulf coast) and a new wave of energy will rotate through the base of a large-scale upper-level trough and head towards the south-central states. This support aloft could help to spawn formation of surface low pressure over the Gulf of Mexico by the middle of next week and, if so, it would have plenty of well-established cold air to work with. Indeed, if this system materializes, there can be significant snow and ice all the way down in the southern states – somewhat similar to last week – and potentially, this shield of snow and ice could work its way north and east into the Mid-Atlantic region. Currently, many computer forecast models “suppress” this mid-week system enough to the south and east that it avoids the Mid-Atlantic region. There are reasons to believe that the impact by this potential mid-week system can shift more to the north and west than currently indicated….stay tuned on that possibility. Looking even farther ahead, there may be yet another wave of energy headed towards the south-central US by late next week and this too can help to spin-up a storm system near the Gulf coast by week’s end or the early part of the subsequent weekend

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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