If the last few days have felt cold, get ready for the beginning of next week. The upcoming pattern looks to bring the coldest weather of the season so far for more than two-thirds of the nation, with temperatures dropping well below 0 degrees for millions.
While the coldest air and most widespread temperature anomalies will hit Monday morning, the chill will be very prolonged as it’s already underway and doesn’t show signs of letting up through at least the first week of January, and likely longer. A perfect setup in the upper atmosphere is allowing for arctic air to directly seep down into the lower 48, and this new pattern doesn’t appear to be going anywhere soon.
Extreme ridging in the western United States due to the combination of a positive PNA and negative EPO (large scale teleconnections that drive the weather pattern in the US), will cause a very deep trough (fancy term for cold front) to sit over the eastern half of the nation through next week. This kind of a setup lets the airflow into the United States come directly from the Arctic.
While the western US will be under a large ridge, cold air will still infiltrate states all the way back to Montana and the Plains. The worst of the cold will likely be found across the central and eastern US though, where temperatures may get as low as 20-30 degrees below average. In terms of actual temperatures and what it may feel like outside, we expect dangerous conditions for many states from the Dakotas to Illinois and right into Pennsylvania and New York.
Monday morning major cities like Duluth, Minneapolis, Omaha, and Des Moines may be waking up to temperatures close to 20 degrees below zero, with wind chills as much as 10 degrees colder. Chicago, St. Louis, and Columbus won’t be much warmer, with temperatures around or just below 0 degrees expected. Further east, much of the same is expected. Some of the biggest cities in the nation, including New York and Boston, could also be waking up to temperatures near or below 0 degrees, while wind chills will make temperatures unbearable. Even further south across southern states, cities stretching from Dallas to Birmingham to Atlanta could be dealing with temperatures well into the teens, with wind chills in the single digits.
Waves of arctic air will continue throughout the week, with temperatures not expected to rebound anywhere east of the Rockies. The cold air will begin to focus more on the eastern half of the country by the end of the week, with temperatures possibly even colder than we’re forecasting for Monday morning. Long-range guidance is painting a nasty scenario of low temperatures 5-10 degrees COLDER then they will be early in the week, this time extending well south into the deep southern and southeastern states. Early signs already hinting at temperatures getting close to freezing all the way towards central Florida.
When will the cold let up? It’s hard to say at this point. It appears we are locked into the arctic pattern for the time being, which will allow very cold temperatures to remain in place for much of the northern and eastern United States as we head towards the middle of the month. After that, it’s likely we’ll see a thaw of some kind, as it’s difficult to get sustained patterns like this for more than a few weeks. The other thing to note is that anytime we see some sort of pattern shift, especially from colder to warmer weather, a big storm is usually thrown into the mix.
For now, stay warm, don’t venture outside for too long if you’re in areas expected to see dangerously cold temperatures, and stay with us through the chill. More to come tomorrow.