Weather Blog - The Heat Builds In Over The Weekend

The Anticyclone
Posted at 7:24 AM, Jul 22, 2021
and last updated 2021-07-22 11:51:24-04

Good morning bloggers,

The heat will build in through the weekend. And, the humidity is on the rise! As a result, the National Weather Service has issued an Excessive Heat Watch through next Wednesday:

Excessive Heat Watch

It has been a rather comfortable July. The first three weeks of the month only had two days that reached 90 degrees. A longer stretch of heat is about to begin today with our forecast high of between 90° and 92° this afternoon. Look at the first 21 days of the month below:

July High Temperatures

An upper level high height area will be forming over the plains states next week. It won't last very long, so a long duration heat wave is unlikely, and it would fit the LRC to have around three days in a row with 95 degrees or hotter next Wednesday through Friday before the next change arrives. Take a look at the "anticyclone" and the "cyclone" on this map below:

Upper Level Flow Next Wednesday

The upper level high is forecast to be over Kansas by mid-next week. There is an upper low over far northern Canada. The flow aloft and the jet stream is reaching its weakest strength and farthest north position of the year. The jet stream is caused by temperature contrast and during the mid-summer months the temperature contrast is the weakest it has been all year. Across the United States, the hottest temperatures have been in Montana and North Dakota this week. So, there is very little temperature contrast. By the first week of August things begin to change and as fall approaches, colder air masses will begin developing in northern Canada and they will start heading south. This will increase the temperature contrast and strengthen the jet stream. For now, we are going deeper into summer during this next week and it will heat up.

The Anticyclone

The air sinks underneath these anticyclones. This sinking air will lead to rising temperatures. The last heat wave we had was from July 17-20, a four day heat wave in 2019. And, the last 100 degree day was in 2018, so it has been three years without a 100 degree day. Let's see how this heat increases next week, but both of these streaks are likely going to end.

Speaking of ending, the pattern shifts enough to have a cold front move our way around eight or nine days from now. We will be monitoring this closely.

Ending To The Heat Wave

There are two build ups of heat expected, with one break in the middle. The break will likely arrive Sunday night into Monday with a chance of thunderstorms and some clouds. We will discuss these developments on KSHB-41 News today and tonight.

Kansas City Weather Time-Line:

  • Today: Mostly sunny and hot. Light south winds 5-15 mph. High: 90°-92°
  • Tonight: Clear and mild. There will be a light south breeze. Low: 72°
  • Friday: Mostly sunny & hotter. High: 94° with a heat index near 100°
  • Saturday: Sunny & very hot. High: 96° with a heat index near 104°
  • Sunday: Mostly sunny & hot. A few afternoon clouds. High: 96°
  • Monday: Mostly cloudy with a 50% chance of thunderstorms. High: 88°

Thank you for spending a few minutes of your day reading the KSHB-41 Weather Blog. Have a great Thursday.