12:15 PM (Friday) | ****Accumulating snow on the way for the Mid-Atlantic with several inches on the table…active, cold pattern to continue well into Feb. with additional snow threats****
Paul Dorian
A high-resolution version of the NAM computer forecast model from 12Z is indicating the possibility of heavier snow bands in the Mid-Atlantic region early Sunday morning associated with the late weekend storm system. Map courtesy NOAA, tropicaltidbits.com
Overview
Moderate cold air will follow the passage of a cold front for the upcoming weekend and attention will turn to the Gulf of Mexico and the southeastern states where a lot of moisture will be gathering. A storm will develop near the South Carolina coastline by early Saturday night and move to a position off the New Jersey coastline by mid-day Sunday. This system is likely to bring another round of accumulating snow to the DC-to-Philly-to-NYC corridor from later Saturday night into Sunday morning with several inches on the table. Looking ahead, very cold air will pour into the interior Northwest, Northern Plains, Upper Midwest and Great Lakes next week and the overall active weather pattern will bring additional snow threats to the Mid-Atlantic region.
Two waves of energy in the upper part of the atmosphere will play a role in the late weekend storm system that will impact the Mid-Atlantic region with a fresh round of accumulating snow. One such disturbance will flow along in the northern branch of the jet stream and another system (circled) in the southern branch will be the main driver of this unfolding event as it will be the catalyst for coastal storm development and intensification. Map courtesy NOAA, tropicaltidbits.com
Details
A strong cold front produced a wintry mix of snow, sleet and rain in parts of the Mid-Atlantic region this morning and its passage later today will usher in a moderately cold air mass for the weekend. There will be two waves of interest this weekend in the upper part of the atmosphere that will play a role in the development of a storm system along the eastern seaboard that will likely bring accumulating snow to the DC-to-Philly-to-NYC corridor. One wave of energy is moving along in the northern branch of the jet stream and a second disturbance is pushing to the northeast towards the Mid-Atlantic region. It is the southern disturbance that is most important in this unfolding situation as it is quite strong and will be the catalyst for storm development and intensification along the east coast.
The likely timetable for this event in the DC-to-Philly-to-NYC corridor is from around midnight or so on Saturday night to around mid-day on Sunday with the snow moving from southwest-to-northeast. Preliminary snowfall estimates are 3-6 inches for the immediate DC-to-Philly-to-NYC corridor and there can be isolated higher amounts; especially, in those locations that experience mesoscale heavy snow bands. Unlike the long duration major winter storm of earlier this week, the late weekend system will move along at a pretty good clip and the precipitation will take place in about an 8-12 hour period. While the bulk of this upcoming winter storm event should feature snow in the DC-to-Philly-to-NYC corridor, there can be a brief mix of snow and rain at the onset and perhaps again on Sunday as the precipitation winds down.
The upcoming weather pattern will feature some much colder-than-normal conditions in the northern and central US with a concentration of the cold in the region extending from the interior Northwest to the Great Lakes. This particular forecast map depicts temperature anomalies across the US averaged over the next 8 days (2/5- 2/13).
Looking ahead
While temperatures may bounce back and forth in the Mid-Atlantic region over the several days, it looks like a more sustained period of colder-than-normal weather will begin in about a week to ten days. For the foreseeable future, the brunt of the upcoming cold wave will be centered in the region from the interior Northwest, Northern Plains, Upper Midwest to the Great Lakes. A widespread very cold air mass will drop southeastward early next week from southwestern Canada into the northern and central US. This pattern will bring bitter cold to places like Bismarck, ND, Minneapolis, MN and Chicago, IL where they can have an unusually long period of time with below zero air temperatures. This cold air mass will be anchored by a very strong Canadian high pressure system that will edge only slowly to the south and east next week from Canada into the northern US.
This forecast map from the 00Z GEFS depicts 2-meter temperature anomalies across the US averaged over the 7 day period from February 13th to February 19th. The much colder-than-normal conditions are still concentrated over the central US, but they expand in a slightly modified form into the eastern US. Map courtesy NOAA, weathermodels.com
In addition to the cold, there will continue to be plenty of energy in the atmosphere next week and beyond in this active weather pattern. As a result, additional snow threats are likely in the Mid-Atlantic region with two time periods showing potential – the middle of next week (Tues. 2/9- Wed. 2/10) and then again during the late week and/or weekend (i.e., Fri. 2/12- Sun. 2/14). The mid-week threat will probably not be too significant; however, the late week/weekend potential is quite high, in my opinion, as I believe there will be a ton of available moisture. It is possible that the eventual departure of this potential late week/weekend system ends up “opening up the flood gates” in the atmosphere to allow for some of the very cold air to charge eastward from the middle of the country into the Mid-Atlantic region.
There is great potential for some extremely cold air across the Northern Plains and Upper Midwest during the next couple of weeks. This is a forecast map for Saturday, February 13th with some absolutely amazing 2-meter temperature anomalies across the Upper Midwest. Map courtesy NOAA, Weather Bell Analytics
Stay tuned…an interesting weather pattern unfolding for the next couple of weeks.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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