MINNEAPOLIS (KMSP) - In what could be one of the most glorious weekends in recent memory, November has started out mind blowingly warm. Saturday temperatures rose 25 to 35 degrees above average region wide and obliterated records across the area. The Twin Cities set a record high of 73°, breaking the previous of 71° set back in 2001. Duluth, St. Cloud, Mankato, Rochester, Eau Claire, and La Crosse also broke record highs for the date. So why so warm? Well, the simple answer is that temperatures at many levels of the atmosphere are extremely warm supporting very warm temperatures here at ground level too. But there’s more to it than that. Let me drop some advanced meteorology knowledge on ya.
So the record warmth has to do with the thickness of the atmosphere also. I know you’re either scratching your head right now, or your head just exploded, but let me explain.
The atmosphere is made up of trillions upon trillions of little air parcels containing all of the gases we need to live and breathe; oxygen arguably being the most important. Well, when these air parcels warm or cool, they have to follow the laws of physics which directly correlates temperature to size. The warmer objects have to get bigger and the cooler objects have to get smaller. Think of it like putting a ring on your finger… or maybe more accurately, trying to get it off. If you try to take a ring off your finger when your body temperature is warmer… like you’ve been outside in the heat or just got done working out… it can be hard or even impossible because every part of your body swells ever so slightly. The opposite happens when it’s cold; your body shrinks ever so slightly. Well, the same thing happens to every air parcel in the atmosphere; they grow and shrink ever so slightly depending on their temperature. Multiply that change in size by all of the parcels in one spot in the atmosphere, and it grows into a measurable distance.
So how much can the atmosphere really grow and shrink?? Well the troposphere (the part of the atmosphere where we live) can easily be 45,000 feet tall or taller in the summer. But when temperatures plummet in the winter, the top of the troposphere could actually be less than 30,000 feet. That means, in the middle of January, the plane you take to get to your warm vacation destination could actually be flying in the stratosphere. Crazy right?
Well, one of the images above is the frequency that the atmosphere expands to the level it is at now thanks to the warmer temperatures. The bright yellow areas shows that 1 day, between October 26 and November 16, every couple of years sees the atmosphere expand to the current levels. For the metro though, it’s the bright red, which means the atmosphere has NEVER expanded to its current height between October 26 and November 16 in the satellite era (since 1979). That just shows how truly unusual this kind of weather really is at the end of October and the beginning of November.