3:30 PM | ***Significant pattern change for the central/eastern US begins next week and it should have some staying power…strong storm system early next week...an eye on President's Day weekend***

The temperature pattern across much of the nation will flip from the current warmer-than-normal conditions to colder-than-normal by late next week/weekend. Map courtesy ECMWF, tropicaltidbits.com

Overview

All systems are go for a significant pattern change in the central and eastern US beginning next week and this change to colder-than-normal looks like it will have some staying power. In fact, an on-going stratospheric warming event suggests the upcoming pattern change to colder-than-normal can last all the way into the middle of March in the eastern half of the country. The front-end of this transition in the overall pattern is likely to come with a strong storm system in the Mid-Atlantic and Northeast US during the first half of next week. There will be a lack of cold air at the onset of this storm system which is likely to limit the chances of accumulating snow in the immediate I-95 corridor; however, significant snow will be on the table for interior, higher elevation locations of the Mid-Atlantic region and Northeast US. If this early week system fails to produce snow in the I-95 corridor, snow lovers should be happy to hear that other threats are quite likely down the road given the upcoming significant pattern change. Indeed, one such threat could take place during the President’s Day weekend.

The temperature pattern across much of the nation will flip from the current warmer-than-normal conditions to colder-than-normal by late next week/weekend. Map courtesy ECMWF, tropicaltidbits.com

Significant pattern change

Temperatures have been well above normal across the central US in recent days and will be on Friday and Saturday in the eastern states. In fact, temperatures on Saturday afternoon can peak in the upper 50’s-to-middle 60’s in the DC-to-Philly-to-NYC corridor ahead of an incoming cold front which is well above normal and this is despite the likelihood of plenty of clouds and potential PM shower activity. However, the cold frontal passage later this weekend will begin a transition to colder weather conditions in much of the eastern half of the nation that likely will have some staying power.

A third “burst” of stratospheric warming will take place during the next ten days or so and this increases the chance for colder-than-normal conditions lasting well into the month of March across the central and eastern US. Maps courtesy NOAA (current - left, 10-day forecast - right)

Support for a pattern change to colder-than-normal across the central and eastern US - and one with some staying power - comes from a recurring stratospheric warming event over the polar region of the northern hemisphere. This repeated stratospheric warming has already disrupted the polar vortex twice this winter season and it looks like it will do so again. There was one spike in upper atmosphere temperatures that lasted from late November into mid-December, a second burst during the early and middle parts of January, and a third warming episode is looking very likely during the next ten days or so. It is the second spurt of stratospheric warming that supports the notion of a pattern change to colder-than-normal beginning around the middle of February (i.e., next week) across the central and eastern US as there is usually a lag time of about 4-6 weeks for an impact on temperature patterns across the US. A third surge of stratospheric warming over the next ten days or so can play an important role in extending a colder-than-normal pattern well into the month of March given the 4-6 week time lag. This does not mean that every single day from mid-February to mid-March will be colder-than-normal in the central and eastern US – that will not be the case - but it does suggest that this upcoming 30-day time period is likely to average below-normal temperatures across much of the eastern half of the nation.

A strong storm system is likely to accompany the front-end of the upcoming significant pattern change that is on the way for the central and eastern US. Map courtesy NOAA, tropicaltidbits.com

Storm early next week (and a long-term hunch)

It continues to look like the front-end of the transition early next week to an overall colder-than-normal weather pattern will come with a strong storm system to deal with in the Mid-Atlantic region and Northeast US. An initial low pressure system is likely to push northeast from the Tennessee Valley later Monday into the eastern Ohio Valley or western Mid-Atlantic and then a secondary storm will likely develop by early Tuesday near the east coast. There will be little in the way of cold air established across the northeastern states at the onset of the storm; however, rapid intensification on Tuesday along the NE US coastline will likely cause a rapid infusion of cold air into the system from the north and west. As a result, while odds favor mainly rain for much of the Mid-Atlantic region, significant snow is on the table for interior New York State and much of New England. Keep in mind, this storm is still several days away so stay tuned. It’ll turn very windy (NW winds) and quite cold on the back side of the storm by the middle of next week…all part of the significant transition to colder-than-normal conditions in the eastern half of the nation that is likely to have some staying power.

One final note, this upcoming colder weather pattern will likely bring about additional snow threats so if the Monday/Tuesday system doesn’t produce accumulating snow in, for example, the I-95 corridor, other chances are sure to follow including, for example, sometime during the President’s Day weekend (just a hunch).

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

Follow us on Facebook, Twitter, YouTube

Vide discussion: