Monday 11:50 AM | **Very active pattern with multiple waves of energy and snow threats to monitor…very windy and cold at mid-week**
Paul Dorian
Very cold air heads into the Mid-Atlantic region by mid-week and the cold will be accompanied by very strong NW winds (i.e., much lower wind chills); map courtesy NOAA/EMC, tropicaltidbits.com
Overview
The biggest weather story of the week in the Mid-Atlantic region is likely to be the bitter cold coming at mid-week because of its unusual nature for this time of year; however, there are also multiple waves of energy in the northern branch of the jet stream that can cause snow on numerous occasions during the upcoming five days or so. The first upper-level system to monitor is likely to generate some snow and/or rain shower activity in parts of the Mid-Atlantic region and there can be some snow squall activity as very cold air pours into the region later tomorrow into tomorrow night. After a very windy and cold day on Wednesday, a second wave of energy will drop southeast towards the Mid-Atlantic region on Thursday and it could generate some accumulating snow in a very cold air mass. Another snow threat will come late Friday into Saturday as a couple of waves of upper-level energy try to consolidate near the Mid-Atlantic coastline and the result could be some more snow for the I-95 corridor region from DC-to-Philly-to-NYC.
12Z GFS surface forecast map (left) and 500 mb forecast map (right) for Tuesday evening; map courtesy NOAA/EMC, tropicaltidbits.com
Tuesday-Wednesday
Strong upper-level energy associated with an Arctic blast will drop into the Northeast US on Tuesday with its biggest overall snow impact likely to be across interior sections of New York and New England as well as across the eastern Great Lakes. However, as this upper-level feature intensifies (i.e., takes on a negative tilt) late tomorrow and tomorrow night, there can be some snow shower activity into the I-95 corridor region and perhaps even some heavier snow squalls as well. Winds out of the northwest will pick up significantly on Tuesday night and continue strong on Wednesday with gusts to 40 mph possible and actual air temperatures will struggle to pass the 30 degree mark.
12Z GFS surface forecast map (left) and 500 mb forecast map (right) for Thursday morning; map courtesy NOAA/EMC, tropicaltidbits.com
Late Wednesday night/early Thursday
Another wave of energy will drop southeastward across the Upper Midwest on Wednesday and then into the Mid-Atlantic region by early Thursday. "Liquid equivalent" precipitation amounts will not be too high with this system, but the air mass will be so cold, "snow-to-liquid" ratios will be quite high. In other words, it won't take much "precipitable water" to generate snow accumulations in the Ohio Valley and likely in the I-95 corridor as well; especially, to the north of the Mason-Dixon Line. Given the fact that temperatures will be quite cold for an extended period of time ahead of this system, any snow that falls late Wednesday night and early Thursday can quickly cause some road issues - just in time for the AM Thursday commute.
12Z GFS surface forecast map (left) and 500 mb forecast map (right) for Friday evening; map courtesy NOAA/EMC, tropicaltidbits.com
Friday
Yet another strong wave of energy will drop southeastward into the eastern US on Friday and a second upper-level system will be heading across the Great Lakes. As these two upper-level features try to phase together late Friday, low pressure is liable to form near the Mid-Atlantic coastline. As a result, snow is again possible in the I-95 corridor in the late Friday time frame with temperatures likely to be cold enough to support the white stuff. If these two upper-level systems can consolidate quickly enough - and it is still just too early to tell - it could get quite interesting around here at the end of the week. Stay tuned.
Monday AM video discussion:
Meteorologist Paul Dorian
Vencore, Inc.
vencoreweather.com