12:45 PM (Fri.) | *Volatile weather pattern to continue next week and beyond…cold blast may arrive in the eastern US by Christmas Day...late week Arctic front could be accompanied by heavy rain/snow*
Paul Dorian
Signs continue to point to a significant cold blast later next week for the central and eastern US - and just in time for Christmas Day (Friday). Map courtesy NOAA, tropicatidbits.com
Overview
The first major winter storm of the season for the Mid-Atlantic/Northeast US has just passed and the overall weather pattern is likely to remain quite volatile through the remainder of the month. There will be numerous strong waves of energy in coming days that will head into the eastern states. In addition, all signs point to a continuation of cold air outbreaks for the central and eastern US over the next couple of weeks. In fact, perhaps the coldest air mass of the season so far could push into the central US by the middle of next week and arrive in the eastern states by Christmas Day (Friday). There is also a chance that heavy rain and accumulating snow will accompany the arrival of the cold blast late next week in the Mid-Atlantic/Northeast US.
A threat to monitor early next week will feature two waves of energy that may phase in time for the development of low pressure near or along the east coast - something to monitor next few days. Map courtesy NOAA, tropicaltidbits.com
Energetic pattern with continuation of cold air outbreaks
The mid-week major winter storm that resulted in accumulating snow in many parts of the Mid-Atlantic/Northeast US areas has left much colder-than-normal air in its wake and some locations will experience their lowest temperatures of the season so far in the overnight hours. In fact, many locations along the I-95 corridor are likely to see late night lows in the lower or middle teens; especially, in those spots with widespread snow cover (e.g., suburbs of Philly and NYC). There are numerous reasons to believe additional cold air outbreaks will drop southeastward into the central and eastern states in coming days from the northern part of Canada. In fact, one such cold air outbreak that could be the coldest air mass so far this season is likely to the central US by the middle of next week and then perhaps into the eastern states by Christmas Day (Friday).
Deep upper-level trough of low pressure will accompany the arrival of a powerful Arctic cold front late next week in the eastern US. Map courtesy NOAA, tropicaltidbits.com
In terms of the potential for storminess in coming days, there are two periods of interest next week that will bear close watching. On Monday, there will be two separate waves of energy in the eastern half of the nation with one pushing northeast from Carolina coastline and the other dropping southeast across the central Plains. These two waves will eventually interact with each other and - depending on the timing - they could help to generate low pressure near the east coast in the late Monday/Tuesday time frame – something to monitor next few days.
An Arctic cold front may arrive in the eastern states late next week with heavy rain (green, yellow) on its front side and accumulating snow (blue) behind it in the advancing cold air mass. Map courtesy NOAA, tropicaltidbits.com
Later in the week, a strong Arctic cold front at the leading edge of potentially the coldest air mass so far this season will be crossing the central states and towards the eastern seaboard. The front may arrive in the eastern US on Thursday, December 24th with mild weather and heavy rain on its front side and accumulating snow behind it in the advancing cold air. The mild weather and heavy rain ahead of the front could melt quite a bit of the snow that is now on the ground in the Mid-Atlantic/NE US. A deep trough of low pressure will accompany this powerful cold frontal system and low pressure could form near or along the east coast in the frontal boundary zone region that will feature a very tight temperature gradient.
An Arctic cold front may arrive in the eastern states late next week with heavy rain (green, yellow) on its front side and accumulating snow (blue) behind it in the advancing cold air mass. Map courtesy NOAA, tropicaltidbits.com
This type of scenario often results in a greater chance for accumulating snow across interior sections of the Mid-Atlantic/Northeast US, but it is something to monitor - even for the immediate I-95 corridor where a “rain-changing-to-snow” possibility cannot be dismissed this far out. Temperatures often drop very quickly immediately behind an Arctic front like this and this could be quite a problem in those areas that do change from rain-to-snow. Also, this type of Arctic frontal passage can lead to a significant “lake effect” snow event for the Great Lakes. Whether or not accumulating snow actually materializes, it appears quite likely that a very cold air mass will arrive just in time for Christmas Day (Friday) in the Mid-Atlantic/Northeast US.
Stay tuned…this interesting weather pattern is likely to continue into January 2021.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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