A couple of warmer afternoons will give the false impression of a danger in the winter: that the winter has finished its business, and is about to take leave. As forecasters have been observing the state of the atmosphere, both on the neighborhood scale and stratospheric scale, they have continued to repeat one message: February is a month that can still topple commute, put a strain on heating systems, and make routine chores a cold weather problem solving exercise.
In recent briefings, meteorologist Max Schuster has put the present arrangement in the context of a kind of a “reload,” instead of a retreat, he explained a dip in the jet-stream that has enabled Arctic air to spill unusually far south. What has come about is the type of unreal cold that is read like folklore until it is experienced firsthand such as the Florida periodic occurrence of “falling iguanas” where sub-zero air causes a temporary freezing of cold-blooded creatures. In Florida, it is simple, as soon as the temperatures approach the freezing point, reptiles are allowed to enter into the state of the so-called “torpor” and lose the ability to control their muscles.
The same trend has also provided scarcity of the Southern snow amounts that require improvisation as opposed to expertise. A recent storm was described by Schuster to have “overperformed significantly” in portions of North Carolina, where 12 to 18 inches were recorded in a band along the North Carolina border near Asheboro and Greensboro, and at nearby Raleigh 2 to 3 less was received, where the storm was cut off by dry air. The specifics do not matter as much as the experience: when it is unusual, people get used to it fast, either creatively or unpredictably, and the difference between what is available is low when the cold is long enough to allow the meltwater to refreeze during the night.
The day-to-day forecasts are given behind a greater number of signals that aids in explaining the reason why the cold can be persistent even when the individual storms appear small. The long-range team at AccuWeather has cited chain reaction: further Arctic intrusions contribute to the snow cover and more ice on the Great Lakes, which leads to less of the “modifying effect” of the open water that otherwise cools the incoming air masses. AccuWeather lead long-range meteorologist Paul Pastelok, made it simple: “because the ongoing cold has led to a rapid increase in ice cover on the Great Lakes, the modifying effect of the shrinking open water is progressively being reduced.” Practically that may be the stiffer night-falls, and colder air clinging together in transit.
Meanwhile, snow risk is not whether or not a storm will “hit,” but what type of snow will be deposited. Virginia Tech meteorologist Barrett Gutter has underscored the importance of the snow-to-liquid ratio, which may vary considerably depending on the temperature and moisture. “Very dry snow… can have SLR values closer to 20:1… while very wet snow… can have SLR values closer to 6:1,” two snowstorms at equal moisture content may have very different measurements–and very different cleanup bills.
Schuster has also called attention to Alberta clippers as the type of small sounding systems which are capable of piling effects one after the other: a burst of light to moderate snow, then wind, then another blast of cold air. The same weak spots are commonly challenged by those sequences: plowed roads freezing, pipes straining, heating systems that cannot be off, when there is not much time between the events.
The more distant issue is further up the scale. In prediction, there is a possible polar vortex disruption, which is associated with the stratospheric warming, a configuration that has the potential to disrupt the circulation that normally seals the coldest air near the Arctic. The alert issued by Schuster has been not of a single named storm but of what he actually contends is the engine room of winter: that it is possible that even in February, the season still has the power to give a wider, deeper dose of cold, when so many are already beginning to hope that the season is coming to an end.
