Wait! Don’t go digging into your closet to find your winter jacket in that bin of winter clothes just yet. The Polar Vortex may “technically” be returning next week — but it isn’t so “polar” in air quality, and it may not be by other definitions as well. So is it really a Polar Vortex at all? The meteorological community is up in arms today over the usage of the term — and the end result is, of course, leading to varying opinions and arguments. The cause of the argument itself is the modeled approach of a massive upper level troughing system, which will feature much below normal temperatures both aloft and at the surface. The track, size and orientation of the system bear many resemblances to the Polar Vortex which tracked through the Great Lakes this past January.
Still, the time of year makes the sensible weather results quite different. Temperatures which are 10-20 degrees below normal (or more in some locations) won’t quite drop the thermometer near the freezing mark. But, still, things could get quite cool over the Great Lakes and Ohio Valley. Some meteorologists prefer to call the incoming system a Polar Vortex, others don’t. But the bottom line has to do more with meteorology than terminology — and the sensible weather effects are becoming more clear as we move closer. Figure 1 shows temperature anomalies at 850mb as forecast by the GFS next week. Notice the broad area of well below normal temperatures as a result of the large upper level troughing system with cold air moving south from Canada.
In our area, the focus will turn to the systems cold front which will shift through the area early next week. The Western Atlantic Ridge currently centered just to our east will build toward our area early next week — resulting in an increased southerly flow and warming temperatures. As the massive upper level trough moves through the Great Lakes, a powerful cold front will shift eastward, eventually through the Northeast US on Tuesday. A low pressure system to our northwest will aid in the cold fronts passage and development of storms.
Depending on the exact timing of the front, severe weather could be possible throughout a broad part of the Northeast US (more on this later today). But regardless of that, cooler temperatures will shift rapidly eastward by the middle part of next week. Still — the “Not-So-Polar” Vortex won’t ever take a massive grip on the Northeast US, as it will elongate and slide to our northwest, owing to the Western Atlantic Ridge.
Whether polar or not by definition, the large upper level trough early next week looks likely to disrupt our areas weather — starting with the potential for severe weather and ending with cooler than normal temperatures. Which makes the exact terminology we use to describe it seem somewhat trivial, doesn’t it?