AccuWeather lead long-range meteorologist Paul Pastelok said in an online forecast, The deepest into the winter is mostly to the east and central states.
That sentence is almost thawing to people throughout the central and eastern United States, who have been dealing with hard freezes, snow-covered commutes and the minor exhaustion of the repetitive cold alerts. Prognosticators also predict a calmer period: Pastelok has indicated that there is no warning of any Arctic air encroaching upon the central or eastern U.S. in the near future, and an outlook of AccuWeather does not show any further cases of severe to extreme cold throughout the rest of the season.
That relief is easily explained meteorologically, meaning that the deep pool of deep cold, which can be used to serve the time-honored “polar vortex” splashes, has remained in place. Weather Trader meteorologist Ryan Maue wrote that the reservoir of the main polar vortex cold pool is more or less locked up over Canada north of the Arctic Circle and, he wrote, the winter [?] is really turning the corner into the home stretch. The real-world impact is not the cessation of winter climate, but a diminished risk that the large mid-western and eastern parts of the U.S. will revert to the type of perennial, debilitating frost setting midseason calamities.
However, it is late winter which turns the patterns of the atmosphere around very fast-a process sometimes disproportionate to what may appear on a seven day forecast.
One of them is that the polar vortex is not a story on the surface. Nobody can predict the next time the Arctic will experience a sudden change in the stratospheric circulation, but forecasters abroad are monitoring that, by watching sudden changes in the overhead circulation, they can identify and predict the next time the jet stream will be rearranged. Other accounts of this type of interference relate to sudden stratospheric warming where temperatures in the air high in the atmosphere increase suddenly and can be attributed to a reversal of winds in the stratosphere. When that occurs, the air that is close to the ground sometimes does not react immediately, rather, it happens later when the jet stream adopts bigger northsouth loops that take the cold air to new destinations. This gives no street level script, but it does give a reason as to why a weak spell can be accompanied by nervous omens farther along.
Judah Cohen is a polar vortex scientist who has called on people to refrain in pronouncing winter over. Cohen posted this in his blog, he wrote, the coming predicted pattern inversion of cold Western US and mild Eastern US is not a permanent one in my view. I suspect at late end of February or early March the trend will turn back to the preponderant trend of the winter mild Western US and cold Eastern US, albeit just temporarily. He included a late-winter reality check that any person who is preparing to take another swing needs, namely that cold in March is very different in cold in January and snows are more and more dependent on elevation. Pastelok also warned that the vortex can recur in March- possibly letting cold air in western Canada into the East- but said that it would be “extremely late” to interfere, and said that effects would be slight.
Although it does not need a dramatic comeback, even without that, late winter bears its dangers, and they come with the warmup itself. New risks, Pastelok has advised, will occur as a result of the warm up because colder, stormier weather will approach the western hemisphere of the country, but it is a reminder that the weather risks in the country do not occur all at once. Long cold periods in the Northeast and Midwest have also contributed to formation of large ice on waterways; increased temperatures have also posed the possibility of ice jams and ice-jam surging, particularly along non-tidal portions. Pastelok explained, warmer temperatures will melt the snow and ice in the next few weeks and this can cause ice jam and river floods earlier than the usual time, along the Mississippi and Ohio rivers, in particular.
Even in case the worst air has softened, snow, too, still is live possibility. Pastelok has remarked, there can be some larger snow events that affect the upper Midwest, Great Lakes and interior Northeast to the end of February into March. That is, the season could soften without completely relinquishing it, exchanging deep-freeze strength with a more chaotic combination of thaw, refreeze and storm-track surprises, all of which still affect daily routine.
