It was the coldest winter on record... it was the warmest winter on record
Let's start with the cold, which has gripped much of the Upper Midwest and Great Lakes area for several weeks. The National Weather Service in Marquette, Michigan posted a note declaring the winter of 2013-14 the coldest in recorded history across Upper Michigan with records going back 113 years.
Some other highlights:
* The average temperature at the NWS office in Marquette was 7.5 degrees -- shattering their old record of 8.5 degrees set in 1963.
* Marquette went 75 days in a row without reaching the freezing mark, besting their old record of 72.
* Marquette has had five days with a high below zero -- third most, and a record 49 days going below zero at some point.
* Their February was the coldest on record.
* They dropped to -1 on Feb. 27 -- their latest below zero temperature by five days.
Here is a good map illustrating Marquette's chilly winter:
But it wasn't just Michigan -- check out Wisconsin and upper Minnesota!
Eau Claire, Wisconsin tied their coldest winter, while Green Bay had their 2nd coldest, St. Cloud, Minn. was 4th coldest, Minneapolis had their 9th coldest, Milwaukee was 10th, and Madison was 11th coldest.
Need some warmth? Head West
Meanwhile, it was the opposite story in the West -- especially the Desert Southwest -- where typically mild winters were even warmer than usual.
Both Las Vegas and Tucson reported their warmest meteorological winter on record -- Las Vegas going back to 1937 and Tucson records going back to 1895.
For Las Vegas, the average temperature (factoring in high and low) was 52.3 degrees, breaking the old record of 52.0. For Tucson,
For Tucson, it was an average 56.9 degrees, breaking the old record of 56.6.
Some other Tucson notes, from their local office of the National Weather Service:
* 6 consecutive days with highs 80 degrees or warmer -- second longest on record.
* It hit 88 on Feb. 15th -- their 9th warmest February day on record.
* It only dropped below freezing on two dates -- tying for fewest amount in winter.
* The airport went 44 consecutive days without rain -- 16th longest winter streak.
Pacific Northwest trended a little cool
The Pacific Northwest -- at least at the surface -- trended slightly cooler than normal through the winter, aided by a chilly February and some cool foggy days on the ground in January that kept official temperatuers down despite a generally very warm atmosphere. Spokane ended up 2.9 degrees below normal as an average, while Hoquiam was -1.7, and Downtown Seattle was -1.5. However, Sea-Tac Airport (the official Seattle station) was about spot-on normal (-0.1).
Why such a dichotomy between the Great Lakes and Deserts?
There was a very persistent pattern across North America for much of the winter, with a large ridge of high pressure blocking the West. That ridge not only brought warm weather here, but also pushed arctic air in the Northern Yukon and Alaska down the ridge's eastern boundary right into the Upper Midwest.
The pattern itself is fairly common in the winter, but the fact it was so stubborn just kept a conveyor belt of arctic air into the Upper Midwest, while keeping the cool winter storms away from the West.
Note the ridge weakened during February, allowing the jet stream to drive a number of Pacific storms through the Pacific Northwest and giving us among our Top 10 wettest Februarys on record. But the ridge was still strong enough to protect the Desert Southwest for much of the period.
It's a great example and rebuttal to those who would take one solitary weather event in one location and attribute it to, or against global climate change. (Remember, it's "global"!) Climate change is the gradual long term shift in climate, not related to one arctic snap or heat wave.
Here we go again?
While the Northwest is expected to remain wet through the weekend, the medium range forecasts suggest a return to what we've seen much of the winter so far. Here is the 8-14 day forecast and, you guessed it, warm in the West; cold in the East.
Special thanks to UW Research Meteorologist Mark Albright and Reid Wolcott from the Las Vegas National Weather Service office for much of the data.