Yes, it's that time of the year again. Fall may not officially start until Wednesday at 10:09pm, but many folks are already yearning to know how this winter will shape up in North Central Wisconsin. How much snow will fall? Will it be brutally cold? How soon will you be able to break out the snow mobile?
First off we have to start with how warm or cool the waters are out in the western & central Pacific. That's right, our focus starts here because the Pacific Ocean water temps out there influence how the jet stream will be aligned upstream into the U.S. Last year we were in an El Nino pattern, in which the ocean water temperatures in this region of the Pacific were running 1-3 degrees Celsius above average. This year the tables have quickly turned and a La Nina is ongoing as the equatorial Pacific sea surface temps (SST) are currently 1-2 degrees Celsius below average. Here is how this effects the jet stream, in particular the map labeled "La Nina".
As you can note, a blocking ridge of high pressure in the vicinity of the Gulf of Alaska pushes the jet stream up to the north in Alaska, while farther east into the western Great Lakes, provides a likely path for cold air to drive southbound into Wisconsin. This translates to better odds of Alberta Clipper type storm systems moving in our direction, which tend to re-enforce arctic shots of cold air, while at the same time provide opportunities for some snowfall. A majority of the time, the heaviest snow is lake effect related, with light to moderate snowfalls from time to time based on how much moisture a particular wave of low pressure can muster for those locales away from the lakes.
So that leads to when was the last time we had a similar type of pattern and how in influenced our winter weather? Looking back in the record book, previous La Nina winters were in 2007-08, 2000-01,1999-2000 and 1995-96. Comparing these years to the average numbers, 3 out of 4 ended up being colder than usual by 2 to 2.5 degrees F, with the exception being in 1999-2000, when it was 4.8 degrees F above average. As for snowfall, those 3 years that we had the cold air in place lead to above average snowfall. In 1995-96 (100.3") the 2nd highest on record, 2000-01 (63.4") and 2007-08 (78.1"), while the mild year of 1999-2000 (48.7"), Average snowfall in Wausau during the winter is 58.6".
Now on to the predictions being made by the Farmers' and Old Farmer's Almanacs, along with my own.
For the Winter of 2010-2011:
Farmers' Almanac: The Great Lakes Region will be Cold & Very Snowy.
Old Farmer's Almanac: The western Great Lakes will be Cold & Dry. In particular, temperatures will be 2 to 3 degrees below average, with the coldest times being in mid-December, much of January and early to mid February. When we do see snow it would be during the later portions of December through February.
Based on historical data and the prospective jet stream patterns for the months ahead, that would lead me to believe this coming winter will be colder with near to a bit above average snowfall.
So in essence, there is agreement that it is going to be chilly this winter (certainly colder than last winter). Snowfall/Precipitation is where there is some variance.
Now one or both of these weather almanacs claim that they are "80% accurate." In reality, I would be surprised if they were even in the ballpark 20% of the time based on their predictions. In order to verify their statements, why not check out their track record from last year and even years before that. We'll start off with last winter.
For the Winter of 2009-2010:
Farmers' Almanac: The Great Lakes Region will be Frigid and Dry.
Old Farmer's Almanac: The coldest weather in the country will be found in the Great Lakes, with temperatures 3-6 degrees below average. In addition it will be a snowy winter. The coldest stretches will be in mid December, early to mid January, and much of February. It even was so bold to say that March would be 11 degrees below average. The snowiest times will be in the second half of November, mid December, early January, the second half of February and most of March.
Meantime, my prediction, which followed along the lines of scientific data and analysis was for this to be a milder winter with lower than average snowfall in Northcentral Wisconsin. I did mention there would be some cold stretches, but taking the typical El Nino winter weather pattern into account, the stormy weather would be to our south and east.
Sure enough, the El Nino pattern did hold true to form for the western Great Lakes. December was a chilly one, with temperatures below average in Wausau and Rhinelander by 0.8 degrees. December did feature a good amount of snowfall with 19.7" in Wausau, 23" in Rhinelander. The biggest storm of the winter took place on December 8-9th as anywhere from 6-12" fell in much of the area. January was mild with temps averaging 3 degrees above average in Wausau and was the 5th least snowiest on record with 2.3". Rhinelander did pick up a bit more snow, that being 6.2", while temps were 4.3 degrees above average. Finally February was more of the same in the temperature department, averaging 2.9 degrees above average in Wausau and 3.4 degrees above average in Rhinelander. There was a bit of snow (6.1" in Wausau, 8.4" in Rhinelander), but still below the typical levels.
So the verdict on the almanacs goes something like this...Farmers' Almanac was wrong on the temperatures, but in the ballpark on drier conditions. The Old Farmer's Almanac was wrong on the temps overall, although mid-December and early January were cold. Meantime in the snowfall category lets just say it was completely off. November featured a trace of snow, mid-December featured a little over 1" of snow, early January only about 1", and the second half of February, you guessed it, only around 1" again. I would be very surprised if March ends up being in the double digits below average for temperatures, but I'll reserve judgment on how much snow could fall.
The moral of this story, don't put all of your weather forecast trust into these almanacs. For those of you that think this is an aberration, check out my previous blog that took into account their predictions from years past: Fun with Weather Almanacs.
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