The Arctic cold front continues to sweep across the eastern half of the country, and by this weekend everyone in the East will feel the chill. The first of several blasts will be a wake-up call, dropping temperatures by as much as ten to twenty degrees below average. Yet, it’s the waves of cold beyond then which may be even more intense.
First Cold Blast:
This first blast of cold air is pushing through the East coast as we speak. On Wednesday, the Northeast and Mid-Atlantic will begin to experience the cooler temperatures while the front stalls near the Gulf Coast, bringing rain to this region. By the weekend however, the cooler air will make it through the Gulf region as well as Florida.
This weekend the cold temperatures will be the most extreme, and will have the highest temperature departures from normal as the trough of low pressure peaks over the Ohio Valley and Mid-Atlantic.
Brief Warm Up:
Once the trough lifts out to the East, there won’t be any dominant height anomaly early next week over the Eastern U.S. What that means for you is that temperatures will be seasonable or possibly slightly above average for a day or two before another push of cold air intrudes.
Second Cold Blast:
This next blast of cold air, which will begin to move into the Midwest and Great Lakes on Tuesday, looks to have a stronger punch to it. Temperatures will likely be farther from average than the previous cold blast. Especially on Wednesday into Thursday, as a lobe of the Polar Vortex makes a quick swipe through the Great Lakes region. This second cool down will impact the entire Eastern U.S., but will be more severe the farther north you are.
This trough will likely lift out by next weekend, but will then be replaced by a third trough of intense low pressure. It’s also worth noting that each of these troughs bring the risk of a coastal storm in the Northeast.
The cold air will dominate the month of December for the East. Our models show that for at least the next fifteen days temperatures will be below average.
For a city like Chicago, the European ensemble mean brings temperatures below freezing for many days. Although by day 15 there will be a moderate to high spread. This spread indicates that the forecast is more uncertain by around Christmas.
The story is pretty similar in New England. For Boston, it’s going to be on the cold side for the foreseeable future. Also notice how the spread, which is the shown by the blue line for each day on the graphic below, is not as significant as Chicago. This represents our stronger certainty in the long-range outlook.