Analysis of the Über Ridge over Alaska on Friday morning from the GFS model. (weatherbell.com)

It’s really cold across the U.S. this week. Temperatures have been running up to 40 degrees below average in the central U.S., and that cold air is now seeping east. Another Arctic invasion, which is expected to be even chillier than this week’s for the eastern states, is expected early next week.

But that’s only half the story.

If you’re looking for where all the warm air went, take a look in the Arctic, where surface temperatures are running up to 40 degrees above average.


Low temperatures were well below the freezing mark (blue) across much of the Lower 48 on Friday morning. (NOAA)

Casper, Wyo., bottomed out at an incredible minus 27 degrees on Wednesday night, blowing away the old all-time November cold record by six degrees. The polar plunge led the Cheyenne Weather Service office to write one of the longest record event reports I’ve ever seen, chronicling the week’s milestones.

Arctic Invasion: Today is coldest of season so far, but worse is yet to come for D.C.

Meanwhile in the Arctic Circle, lows were a balmy 23 degrees on Thursday morning in Barrow, Alaska — the furthest north weather station in the U.S. — a full 50 degrees warmer than they were in the Lower 48. Dozens of daily high records have been set this week across Alaska.


Surface temperature departure from average on Friday morning over the Arctic. (weatherbell.com modified by CWG)

Blame the meteorological flip flop on an über-ridge of high pressure that has built up the west coast of North America into the Arctic Circle. It’s also considered an “Omega block,” since the flow pattern forms an Omega on weather maps.

This week, the jet stream has been towering into the Arctic before crashing down into North America, bringing all of that cold, polar air with it.


Excuse me, Arctic? We’d like our jet stream back. (weatherbell.com)

In fact, the über-ridge is so über-y, it’s shattering Alaska records. Pardon me for a moment while I weather-geek out.

The Weather Channel’s Stu Ostro pointed out this morning that temperatures measured at 5,000 feet blew away the old records in Fairbanks, Alaska, by almost two degrees Celsius. You can see how significant this event is by looking at the previous records he lists, which were only broken by fractions of degrees.

This weather reversal was brought to you by the Bering Sea storm, which pummeled the North Pacific just under a week ago. While that storm was exploding in intensity, it was also forming a massive ridge over western North America. Sea surface temperatures along the West Coast are running up to five degrees above average, and the storm channeled that warmth northward into the Arctic.

But what goes up must come down, a saying that is very appropriate for our weather this week. As that massive ridge was building north into the high latitudes, the cold, Arctic air that used to be up there had nowhere to go but south. Hence, record-smashing cold.

Unfortunately this pattern is forecast to stick around for at least another week, and the Lower 48 are in for another chilly treat on Monday and Tuesday, and this time, the East Coast won’t get off so easy.