Thursday 830PM Update RE: Sunday Feb 13 Mid Atlantic Snow Threat
STARDATE 202202.10 … Captains log
The mid-day models actually moved into somewhat better agreement all though they are still fairly far apart. The Thursday 6z operational GFS and GFS ensembles had widespread 4 to 8-inch snows covering northwest North Carolina all of Virginia except for Hampton Roads Southern Maryland into the Delmarva in Southern New Jersey.
The operational GFS performance this winter has been quite good and at times far superior to the European model but as of midday there is still a significant difference between the GFS model solution versus the Canadian the European in the British models.
The midday operational GFS model came down with the snow totals to some degree but it still has significant 3 to 6 inch snowfall across all of Virginia and into much of the Delmarva except for the northwest corner (Winchester Leesburg) and in Hampton Roads. There was also a pocket of 5–9 inch snow in the central Virginia Piedmont including Charlottesville, Farmville, Lynchburg, Lovingston, and Staunton in the Shenandoah Valley
On the other end of the spectrum has been the last few runs of the European model which have shown move very little accumulating snow in any portion of Virginia Maryland or Delaware from this system on Sunday. The reason for this has to do with the fact that the European model shows a substantially weaker system and because it is weaker the precipitation is lighter and that means that the temperatures hover around 32 or 33 degrees so you don’t get real accumulation. Even so… the European model does have some minor snow accumulations running from southern New Jersey into Delaware and southern Maryland then into central Virginia from Manassas to Richmond then over to Charlottesville and Lynchburg into the southern half of the Shenandoah Valley
The Canadian model has also shown a slight increase when you compare it to what it was showing on Wednesday — when it had almost no accumulating snow anywhere in the Middle Atlantic region. As you can see here the midday Canadian model does show a few pockets of 1 to 2-inch snows in Central Virginia Southern Maryland and the lower Virginia Eastern Shore.
The British model has even less impressive than any of the other models but again it shows a slight increase from what it was showing to its previous Cycles.
The new 18z Thursday operational GFS model has come out and it is essentially unchanged from the 12z run It has reduced the pocket of 5–9 snowfall in the Virginia Piedmont to a 4 -8 inch snowfall but in general it continues to show a 3 to 6 inch snowfall from Southwest Virginia just to the east of Roanoke across the central portions of the Shenandoah Valley the central Virginia Piedmont into Central Virginia Southern Maryland and the Delmarva.
This is supported by the 18z GFS ensemble which has the same general idea of where the best snow is going to fall on Sunday.
Finally the 18z operational European and European ensemble has come out and it remains unchanged from what it was showing at midday. It has a band of 1 to 2 inch snows from Southern New Jersey into the Delmarva Southern Maryland Central Virginia into the Virginia Piedmont and portions of the Shenandoah Valley. In other words, a fairly minor event.
WHAT WE DO KNOW
The precipitation is likely to start off as light rain Saturday night. The only location where the precipitation might begin as snow will be in the central Shenandoah Valley and North Central Virginia. The main event will be from Sunday 4 a.m. to Sunday 4 p.m. DC BAL metro will be on the Northern side of the event While the Roanoke metro area will probably be on the western side of the event. The KEY will be the precip intensity. The fact that the precipitation will fall mostly at night into the morning hours should help with the K snow accumulations to some degree even if the lighter forecast in scenarios turns out to be correct.