Our weather for this Veterans Day weekend looks to be pleasant and fall-like, with one caveat: the possibility of a cold-air damming situation settling in for late Saturday and Sunday.
Cold, arctic high pressure will set up over the Northeast U.S. and extend its reach well down the mid-Atlantic, cold enough to produce record lows in those areas, though Georgia and Alabama will be spared most of the cold. However, the influence of the cold air mass may still be felt here if a CAD (or “wedge”) situation takes shape.
Simply, a wedge happens when a cold air mass bumps up against a mountain range, in our case the Appalachian chain, and because of the barrier the air flows down the range over flatter terrain. For us, this air comes in the “back door” via northeasterly flow, different from the typical cold front that moves in from the north or northwest. These can occur any time of year, even summer, but if they happen in the winter they can result in an ice storm with below freezing temperatures. In most cases, though, it features strong high pressure over the Northeast or mid-Atlantic, and often results in a blown forecast as models have difficulty picking up on the situation.
For our weekend, models are inconclusive. The wedge is almost certain to develop somewhere, but what’s unclear is whether it will be strong enough to reach Columbus or into east Alabama. The toughest part of a situation like this is figuring out when it will end once established, so if it develops here we may see it last into Sunday or it might be in and out quickly. It would be characterized by brisk east or northeast winds, temperatures that may not get out of the 50s or even 40s (!) all day, and at some point an increase in clouds from Atlantic moisture, possible on Saturday but likely on Sunday. There might even be a few light showers develop Sunday in what is essentially a stable-air situation.
Bottom line: if the wedge doesn’t develop all the way to Columbus, it will be a pleasant weekend in the 60s with clouds and some sun. If it does make it here, Saturday afternoon and Sunday could be raw with a wind and downright chilly temperatures most of the day.