STARDATE 202202.09 — Engineers Log
If you recall back in the beginning of the New Year, the last several days of December and the first two days of January were quite mild. Then, a strong arctic cold front arrived, LOW pressure developed on the front, and there was a significant snowstorm for much of the Mid-Atlantic region. This snowstorm event and the amount of snow that fell was under- forecasted which contributed to the monster traffic jam in the northern Virginia, and central Maryland areas on January 3rd.
This upcoming event for Saturday night and Sunday is a rather similar situation, in that right now there is quite a bit of model confusion, but it does look like there is going to be several hours of snow on Sunday. And, just like we saw with the January 2–3 event, the days leading up to this coming Sunday’s snowfall will also be rather mild for much of the Middle Atlantic, especially east of the mountains on Friday and Saturday.
A strong Arctic cold front will move out of the Midwest, cross the Appalachian Mountains and reach the East Coast on Saturday morning and midday. The front will come to a halt across the eastern Carolinas and northern Georgia on Saturday night /Sunday morning. LOW pressure will develop on the front and spread snow in eastern Tennessee, eastern Kentucky, West Virginia, southwest Virginia, the Shenandoah Valley, central and northern Virginia, much of Maryland and Delaware, and southern New Jersey, early on Sunday morning.
As temperatures continue to fall moderate snow will spread into northwest North Carolina and southeast Virginia, and into the rest of the Delmarva, on Sunday. There is some uncertainty as to how much snow is going to fall in the big cities of I-95, north of the Pennsylvania and Maryland state line.
The mountains of western North Carolina should see at least a few inches of snow, and if the track of the LOW shifts any further to the south, that area could see several inches. In southwest Virginia, the Shenandoah Valley, the eastern third of West Virginia, northern Virginia, central Maryland, the northern Delmarva ,and southern New Jersey, this could be a very nice snowfall with amounts ranging between 4 to 8 inches. The entire event will be over before Dawn on Monday.
What is driving this potential event is the phasing of two distinct pieces of energy in the jet stream on Saturday as they move through the Midwest. One piece of energy is in the Ohio Valley, and the other piece of energy is across the Mississippi, Delta. The GFS model is “phasing” or merging both of these pieces of energy at the exact perfect time, which is why we get the LOW pressure development and a snowstorm across the Mid-Atlantic region and perhaps into southern New England. The European model does not show the phasing very well and because it has weaker phasing, it has a much weaker LOW pressure system. It still produces a couple of inches of snow in the Mid-Atlantic, but it is nothing like the operational GFS or the GFS ensemble.
HERE IS THE 12z WED EUROPEAN valid FEB 9
Based upon this current data, it looks like the precipitation will start as rain in the Hampton Roads, and central and northeast North Carolina for several hours before it changes over to snow. Right now, the heaviest snow does not appear to fall in Hampton Roads/ northeast and in central North Carolina. Instead, the early data shows the best / heaviest snow will fall in southwest Virginia, central Virginia, the Shenandoah Valley, and into the Delmarva and southern New Jersey. There is some uncertainty with the snowfall amounts in the DC metro area but the trend seems to be that the further north of DC and Baltimore, the less snow will accumulate. This would imply the heaviest snow will probably be south of Interstate 66, but that is just based upon the current data.
After this event, large-scale changes in the pattern across North America strongly imply that the threat of seeing significant snowfall in the Mid-Atlantic region will come to an end. These maps show that the pattern is going to fundamentally change with a persistent deep Trough in the jet stream across the western third of the CONUS in the last week of February into the first week of March. There will also be an equally strong Ridge in the jet stream across the Southeastern states which can bring sustained mild temperatures. This kind of weather pattern not only prevents Arctic air from pushing into the eastern CONUS, but it forces LOW pressure systems to track in a general SW to NE direction, passing well to the north and west of the Mid-Atlantic region.
All that being true, keep in mind that WxRisk.com is NOT forecasting the end of cold temperatures. We are NOT forecasting “no more snow for the Mid Atlantic”. BUT we must face the reality that after FEB 21–22.. the large scale pattern becomes very unfavorable for significant snowstorms with any sort of moderate or significant accumulations for the rest of the winter in the eastern CONUS. Of course, New England is new England and the Great Lakes are the Great lakes and in both of those areas it can and it has snowed big time until early April.
There is some hint that there might be one last surge in mid-March, but right now, that is just a weak possibility.