There's no secret the coldest air seen in years is on the way on Monday and Tuesday of next week. It has happened before. It will happen again. Why is it such a big deal? It's because it can be deadly if you get stranded, outside in the elements.
I'm going to lead off by saying, while Monday and Tuesday may be the coldest days in the forecast, tonight shouldn't be forgotten either. Already temperatures are pushing to -10° and with a southerly wind picking up overnight, wind chills will be hovering at -25 to -35 mph. Cold enough to cause frost bite in about 15 minutes.
Temperatures moderate for Friday afternoon into early Saturday morning with a strong and persistent southerly wind. Air temps creep back up into the lower 20s in the early morning hours of Saturday. One of the biggest driving factors to the warm up is the breakdown a persistent trough of low pressure that has been situated over the upper midwest since early December. The jet stream is running west to east in a 'zonal flow'. At the surface, some of that warmer air is moving into the region.
But again, just like all of last month, on Sunday that jet stream starts to take a dip. By Monday the trough has redeveloped and rushing in is an airmass that normally resides north of the Arctic Circle.
This is one powerful trough. It's one that borderline nears the extremes statistically which can make forecasting the event particularly difficult.
Believe it or not, looking at historical events with a similar setup to the forecast can point to some clues about what may be on the way. By using the Cooperative Institute for Precipitation Systems Analog Guidance products we can look back at archived situations that most similarly match the upcoming forecast specifics. Yesterday I headed over to the CIPS Analog page with and compared the Monday's forecast with an event from 1984. Today with subtle differences the top match was from a January 18th, 1994. Below is the 4 panel forecast plot from the GFS computer model for 6AM this upcoming Monday morning.
And here's the observed 4 panel from January 18th, 1994 at 6AM.
Note how closely the upper levels of the atmosphere in the four panels match each other.
We can look at certain features of interest, in this case temperatures, on what happened that day. Local low temperatures on that day in 1994 were in the -24 to -28° range.
Here's a look at several computer models and the National Weather Service forecast for temperature (top) and wind chill (bottom) over the next eight days. *Click to Enlarge*
Signs are pointing to a drop of nearly 50° in temps from Saturday morning through Monday morning, bottoming out near -25°. With a wind of 10-20 mph, a wind chill could be as low as -50°!
Also discerned from the graphs above is a 3 1/2 day stretch where temperatures will be below zero!
The Storm Tracker 6 Seven Day Forecast for highs/lows can be found below.
Temperatures dropping pass -20° is rare sight but does happen occasionally in the winter months in southeast Minnesota and northern Iowa. The last time the mercury dropped below that mark was January 15th & 16th in 2009. The 16th even dropping to -26°, a degree lower than what's currently planned for Monday morning.
But the high was above zero. We have -15°/-25° for an average temp of -20° in the forecast. That exceeds the average temp on January 16th, 2009. *********
The high of -15° on Monday would mark the first time we failed to reach -10F since February 3rd, 1996 when the highest maximum temperature was also -15°. Meaning... this would be the coldest day in nearly 18 years. Surely we'd be setting record low temperatures on Monday right? Maybe not. Both the record low and record lowest high both exceed the current forecast by a couple of degrees. Both of which were set in 1912.
Still... it's something you'll want to be prepared for. Sure, temperatures like these are easily managed with today's modern conveniences, however, if you should become stranded, away from civilization, in conditions that are in the forecast it can be very dangerous. If you haven't already, prepare a Winter Survival Kit together and put in your car. Here's a list from the National Weather Service of suggested items it should contain.
Dress for the occasion. Don't wear one bulky item to help keep you warm. Dress in layers. The insulation value is in the pockets of air between each layer, not the layers themselves. The more barriers you put between your skin and the cold air, the warmer you will be. Also avoid over exerting yourself in extreme events.
Take precautions... because with air temperatures reaching as low as -25° with a wind chill as low as -50°, frostbite can form in as little as 5 MINUTES!
Storm Tracker 6 Chief Meteorologist