Bring on the record cold! But it's not moving into the Upper Midwest for the very reason you have probably heard. This upcoming cold snap is NOT because of the Polar Vortex.
The Polar Vortex is an actual meteorological phenomenon. It doesn’t sound like it would be because it sounds ridiculous and somehow became a big part of pop culture, but it is a scientific entity in our atmosphere. However, this cold snap has almost nothing to do with it. This cold snap is because of two reasons... a very large trough that is diving southward AND because Typhoon Neoguri.
How can a typhoon on the other side of the world cause a cold snap in the United States? Well, it’s actually kind of simple (as far as meteorological phenomena go anyway). The atmosphere is just like a fluid. Everything affects everything else because there are no borders, walls, or boundaries. So a typhoon will directly or indirectly affect everything on the planet, especially in the hemisphere it is formed in. When the typhoon moved through Japan and up into the northern Pacific, it brought a lot of warm juicy air with it. This actually pushed the jet stream further north causing a kink in the system. Well, when you throw a rock into a pond you get ripples right? Well, this is the ripple effect. Think of the jet stream like a string… if you kink part of it, the rest of it will probably kink too. That is exactly what is happening here. Take a peek at the picture below.
This shows the jet stream, the river of air at the top levels of the atmosphere. This is the forecast for Monday afternoon across North America. See how the jet stream bunches and travel north to south wildly. That is the kink I am talking about. This sends cold air far to the south in the troughs and warm air far to the north in the ridges. The West Coast will get the warm air, and the central and eastern U.S. will get the cool air.
How cold are we talkin? Well, cold enough to set some record cold high temperatures but not January type cold. The coldest high temperature ever recorded at MSP Airport in July is 58°. It looks like that number will be safe… but the current forecast has us breaking a 130 year old record on Monday with a high of 66°.
Looks like the record is safe on Tuesday… but I think many of us will agree, one day of record breaking is enough.
So how unusual is it to have 60’s during the month of July? It’s not as uncommon as you might think; we have just had so many warm summers in the 21st century that we are a little unfamiliar with what a cool one is like. We actually had one day in the 60’s in July just last year, and a couple back in 2009.