Where is the heat coming from?

Temperatures Monday afternoon reached the upper 80s/ and low to mid 90s across the immediate Stateline with the upper 90s being felt across the corn belt states.  Temperatures today are expected to rise even further than readings yesterday with the heat index back into the triple digits.  So this may have you asking...'Where is this late summer heat coming from?'

To answer that we have to look above our heads and understand what's going on not only with the jet stream but what's going on in the atmosphere.  It took a while for things to heat up across the Midwest and Great Lakes this summer.  The cool weather stuck around a bit longer with late season snowfall and late season snow melt.  This, on a larger scale, tends to throw the balance of Mother Nature and the atmosphere off a little causing a late arrival of some of the heat and humidity.  Unfortunately it looks like as we begin to transition into Meteorological Fall, September 1st, it may not feel so 'fall-like' outside.  More on that to come in a later post!

A strong ridge of high pressure has taken hold of the center of the country with forecast high temperatures throughout Iowa expected to reach close to 100° and temperatures closer to home forecast to reach the low to mid 90s.  Air within the atmosphere under high pressure sinks while air within low pressure rises.  It's the rising air that causes the clouds, rain and thunderstorms and the sinking air that brings clear skies.  Sinking air also becomes compressed
causing it to heat up, therefore causing a rise in temperatures.  Think of a pump you use to pump up a bike tire or basketball.  When you use the pump you may notice it start to warm as the air inside it is compressed.  It's the same concept with the atmosphere.  The closer you are to the center of sinking air the hotter it will be.  This ridge is expected to break down a bit towards the middle of the week but it's not going to do much for temperature relief.  Highs through Labor Day weekend will remain above average and could possibly rise again after early next week!