Arctic Temps Set Record – What Next?

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It’s not been this cold in Fairbanks, Alaska for six years. Saturday morning’s low temperature plunged to 50 degrees below zero. The same day was also the first time in three years that the 24-hour max temp did not rise above minus 40. Minus 40, by the way, is the temperature at which the most widely used fluid in thermometers — mercury — freezes (though less accurate, alcohol freezes at -173F (-114C) and is used in many thermometers where extreme cold and/or HazMat concerns take priority). Fairbanks bottomed at -51 yesterday morning.

Photo: Alaska In

That kind of cold doesn’t just show up one Saturday. It’s been building for the past week thanks to a strong, stable high pressure system and long, long hours of darkness (today Fairbanks will receive just six hours of daylight with the sun so low on the horizon that the solar radiation practically ricochets back into space). It also doesn’t just disappear, which is why today’s YourWeatherBlog is concerned with the recent low temperatures in Alaska’s second largest city.

Cold weather systems typically gain their identity while parking over broad, northern latitude land masses where sunlight is limited and sweeping winds are not common. Add in a snowy or icy ground cover and the ingredients are all in place. Russia’s Siberia comes to mind; so too, Canada’s Northwest Territory. And though Alaska isn’t a prime nurturing ground for such an air mass, Alaska is certainly no stranger to harboring air so cold it can pop a thermometer! So it is with cautionary interest that we look north for temperatures that, some day, may very well decide to move toward more southerly latitudes.

Such is the case today. Computer models, at their core, display movement of air masses. With air masses comes moisture (or lack thereof) and temperature (cold or warm) that not only drives the local day-to-day forecast but typically displace the resident air mass already in place leading to what can be a dramatic change to the forecast. Tracking the air mass responsible for the six-year low temperature in Fairbanks suggests an Arctic outbreak for the Lower 48 that may not set all-time low temperature records, but may be a standout for this 2011-2012 winter season.

But — with computer models also comes a level of confidence that rests squarely on the shoulders of the meteorologist interpreting the data. Sometimes confidence is high; sometimes low. And, more often than not, when looking 7, 10 and 14 days into the future it’s rare that high confidence accompanies the outlook. Again, such is the case today.

GFS operational computer modeling shows the large pool of cold, Arctic air. On the surface, locally cold air will be pulled by gravity but it is the upper-level winds that direct the air mass as a whole. Click for larger image. Image: WSI

What’s the take-away? It could get very cold in some places of the Lower 48 come the second week of February. However, this is quite some time in the future and there should be no surprise that confidence levels still remain low. Not only is there disagreement between several models (how cold, when and where), but any forecast in the 168-240+-hour time-frame should always be viewed with a healthy dose of skepticism.

For now, the temperatures in Fairbanks are warming. Though tomorrow night may again be in the -45F range, most nights following that will be in the -15 to -20F range. Does that mean the air responsible for those temperatures is warming in place? Or does it mean the air mass is on the move and looking for someplace new to hang its hat?

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