2 SNOW EVENTS — one minor event on Thursday… then a MODERARE or SIGNIFICANT SNOWSTORM Friday Pm/ Saturday am for SOME portion of the MID ATLANTIC

STARDATE 202201.18 ….. 1300 EST

This is going to be a complicated forecast because it occurs in two different parts. On the other hand, it is going to be easier to forecast for most of the area because there is going to be little, if any sleet, except for northeast North Carolina and southeast Virginia involved in either one of these events.

THE FIRST EVENT: THURSDAY/ THURSDAY NIGHT

The first event is the arrival of the arctic cold front which comes in on Thursday with rain. As the arctic front crashes the temperatures, the rain will change to snow from north to south Thursday afternoon into the evening hours. All of the models are in strong agreement that this will produce a band of 1 to 3 inches of snow, generally from southern New Jersey, across the central and lower Delmarva, southern Maryland, eastern and central Virginia including Hampton Roads into north-central and northeastern North Carolina. Because the precipitation will be falling as the temperatures crash, and the grounds are already rather cold, melting snow on the roads, once it, begins to accumulate, will freeze.

By 5pm temperatures in Richmond for example will be 27 degrees, Washington 23 Charlottesville and Roanoke 22 degrees, the Shenandoah Valley will likely be in the teens. The Delmarva will also see temperatures by midnight Thursday night in the low to mid-20s. The rain will change to sleet in northeast North Carolina including the Raleigh metro area Thursday night into Friday morning.

We are a little skeptical that the snow band is going to be as much as 1 to 3 inches s the models are depicting. We think 1 to 2 inches seems more likely.

THE SECOND EVENT

Increasingly it looks like the second event is going to be a significant if not major snowstorm (depending on location) for central and eastern Virginia, southern Maryland possibly including Baltimore and DC, the Delmarva, southern New Jersey, Southeast New England/ Cape Cod. Further Inland this looks like plow able snow of several inches for Boston, interior Connecticut, New York City, Philly, the rest of New Jersey Interior southeast Pennsylvania, central and western Maryland, the Shenandoah Valley, southwest Virginia and northern and western North Carolina.

There are three possible scenarios or outcomes for Saturday. The moderate solution, the significant solution, and the extreme / historic snowstorm solution

THE HISTORIC EVENT

The most impressive or extreme solution is the operational European model. For the past seven runs/ cycles, it has shown a historic snowstorm for the Mid-Atlantic region. This image shows you how extreme the European model is. Last week it was the operational GFS model which consistently took the coastal Low inland and the consistency of that model impressed a lot of meteorologists. However, this time around it is the European model which has consistently showed a major if not historic snowstorm for the Mid-Atlantic region but this model does not seem to be given the same respect as the GFS model. The consistency doesn’t seem to be having much of an impact with other meteorologists and other forecast services.

To be sure the European operational model for the past seven runs is extreme. Taken verbatim, its solution would produce a snowstorm that would place in the top 3 snowstorms of all time for the Richmond metro area and in the top 5 or top 10 in D.C and Baltimore, much of the Delmarva, and southern New Jersey. The snow shield is massive, it is impressive, and the snow ratios are quite high. All of these snow maps are based upon the 10 to 1 snow ratio and that is NOT going to be the case with this event except for perhaps northeast North Carolina. The operational European model does bring sleet into the southeast 25% of Virginia and northeast North Carolina for about 40% of the storm which would reduce the snow amounts in those areas.

At this point, we are not forecasting a historic snowstorm for the southern portions of Mid-Atlantic region. The European Ensemble is not as extreme but with each model cycle its snow numbers are going up. As you can see the European ensemble is showing a widespread 4–9” snowfall in the Middle Atlantic region with the heavy snows again in central and eastern Virginia, southern and eastern Maryland into southern, New Jersey. The model is producing widespread 0.25 to 0.75” liquid equivalent Friday night into Saturday morning throughout the Mid-Atlantic region. At a 10 to 1 snow ratio that is a 4- 8 inch snowfall generally speaking. But again we are not looking at a 10 to 1 snow ratio as the arctic air is going to make the ratio more like 14 to 1 or 15:1 ratio. If so then the 4–8 inch snow band becomes 6–12” snow band.

THE MODERATE SOLUTION

The last several runs of the operational GFS model have shown no significant snow with the second event Friday night into Saturday. However, the early Tuesday morning 0z operational GFS did come west and does show a 2–8 inch snow band in the southeast third of Virginia, northeast North Carolina, into the southern Delmarva for Saturday.

The early-morning Canadian model is also showing a moderate snowstorm with a second event. It has a band of 4 to 8 inch snows from north- central and northeast North Carolina, into central and eastern Virginia, including Richmond and Hampton Roads, the Middle Peninsula, the Northern Neck, and the central and southern portions of the Delmarva. The coastal LOW that forms on the front on the Canadian and the GFS models is not nearly as extreme or powerful as on the European and the LOW does not come nearly as far to the North. Both of these models again show a nice band of 0.25 to 0.75” liquid equivalent in the above mentioned areas which equates to a very nice 4 to 8 “ snowfall at a 10 to 1 snow ratio.

The SIGNIFICANT (middle ground) SNOWSTORM SOLUTION

The early Tuesday morning British model is like the European model, but it doesn’t take the LOW as far up the coast so the huge snows do not reach Washington D.C Baltimore, Philly, New York, or Boston. Instead, the British model has a 6 to 10 inch snow band in the central and southern Delmarva, central and southeast Virginia central and eastern North Carolina into central South Carolina. But the British model does show a 12”+ snow band in eastern Virginia, down to Raleigh with the model producing 14 inches at Richmond and 17inches Williamsburg and Franklin Virginia

In looking at the GFS and the Canadian ensembles do show substantially more snow and many of them are showing a major snowstorm. There is even a significant number of GFS and Canadian ensemble members that show a historic snowstorm like the European model is depicting. It is significant in that the GFS and Canadian models ensembles are snowier with a bigger snowstorm on Friday night into Saturday then the regular operational models. The maps with the BLACK DOTS show major Mid Atlantic snowstorms outcomes.

SUMMARY

There are two events coming up for the Mid-Atlantic between now and Sunday. The first one is rain changing to now as the arctic front comes south which will drop a 1–2 inch snow band from Boston to Richmond into Raleigh. The front will also bring some moderate snow into eastern Kentucky and West Virginia. Interestingly, most of the models do not show 1- 3 inch snow band in southwest Virginia from the cold front. I am particularly concerned about the wet grounds/ roads icing up as temperatures crash and the snow continues to fall on Thursday evening.

The event for Friday night into Saturday is looking much more significant. Right now most of the TV stations and NWS continue follows the GFS model. Between now and Friday, if the operational GFS and /or GFS ensembles suddenly turn more extreme like the British or European models, then you can expect a big shift in the weather forecasts on your weather smartphones, TV weather and from NWS.

Right now the model data is too strong to go with the weak GFS solution. It will be interesting this afternoon to see if the extreme European and major snowstorm solutions of the British model hold course or if they change. Eventually one of these groups of models will have to make a significant change over the next couple of days.

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12Z DATA briefly
The mid-day models have increased the snow amount with the arctic cold front on Thursday in all areas of the Middle Atlantic. Interesting

The 12z operational GFS with regard to Friday and Saturday makes little sense. First it pushes the cold front deeper into the SE states than any other model which implies a stronger area of HIGH pressure. Thats fine and it explains Why the op GFS slides the Saturday LOW off to the coast. But then the model develops a second wave of LOW pressure for Saturday night and Sunday and in doing so it magically erodes the Arctic air in portions of the Eastern Mid-Atlantic.

The GFS ensembles pretty much unchanged from what it was showing earlier. And it has the second event on Saturday with a bigger snow shield letting further north into Washington DC Baltimore and southern NJ.

The midday Canadian British models are unchanged.

The midday European model has the bigger storm scenario but IS further off the coast. The result is still a significant 8–15 inch snowfall in north central North Carolina eastern half of Virginia into the Delmarva with 4 to 5 inches in DC -Baltimore Southern New Jersey Charlottesville in Southwest Virginia FULL UPDATE 6PM