11 February 2015
A true outbreak of Polar air is headed for the northeastern quarter of the U.S. beginning Thursday. It will actually come in at least two and maybe 3 waves. The first wave will bring snow showers and plunging temps on Thursday to the East Coast from Virginia to Maine, and another surge will arrive Saturday evening with even colder air.
A true Polar air mass often brings a dusting of snow and we may see some Bay effect snow over the Delmarva Peninsula as the frigid air crosses the Chesapeake Bay. There will not be as much lake effect around the Great lakes because they are rather frozen now. Anytime you have this much Arctic air in place, you have to watch out for a surprise snow event, and the models tend to not do well in these situations. Cold air tends to be tougher to move out than the models forecast, and what may look like a rain event becomes an ice and snow event.
It looks like Boston will get more snow on Thursday night and early Friday, but this will be a rather light few inches. A much more powerful storm may be coming toward the early part of next week though, and this one may be a widespread snow and ice event from Virginia northward. From Maryland northward the temperature will stay below freezing from Thursday evening until at least Tuesday afternoon, and even then it will be only a few degrees above 0 C.
WARM OCEANS EQUAL SNOW
You used to hear people make climate change jokes when we had cold winter weather, but have you noticed how that has mostly disappeared now? I think this shows that we are making progress in educating the public about the science, and the image below shows just how warm the oceans are off the U.S. East Coast. This certainly is a factor in the heavy snow events in New England over the past month.
There was a good piece in USA Today about the Boston snow and warm ocean waters this week. Look for the quote by Dr Kevin Trenberth at NCAR.