The heat and humidity is on the way out as we wrap up this third week of July, and boy was it a hot one! Much of Western Wisconsin spent consecutive days with temperatures in the 90s and heat index values hovering around 100 degrees, especially, late in the week. Below are the high temperatures for the 7 days from July 13th to July 19th during this heat wave.
Temperatures really began to incline on the 14th. However humidity didn’t really rise dramatically and become super uncomfortable until the middle of the week. That’s when those heat index values were topping out over 100 degrees, especially, for folks in the Coulee Region. In Eau Claire, the heat wave maxed out at 97 degrees on the 18th. That same day La Crosse hit 98 degrees. A scorching high temperature they had hit a day before.
So what brought us these dog days of summer? It was all thanks to a very large and stubborn high pressure that was to our east when this heat wave began. That area of high pressure strengthened and actually retrograded back to the west. This graphic shows what the set up ended up turning out to be to keep us so hot for so many days. The jet stream positioned itself well to the north of us keeping any cooler air at bay. The circulation of the high pressure pulled up more warm and moist and air from the Gulf of Mexico. That high pressure really didn’t budge, and we remained in Mother Nature’s oven.
This week’s heat wave tacked on more than double the number of 90 degrees we had seen before this week in Eau Claire. The grand total for 2013 is now up to 7 days with the hottest day being this past Thursday when we hit 97 degrees in Eau Claire. We have a lot of ground to make up if we want to catch up to the number of 90 degrees days that were seen last year. By July 19th in 2012, we had seen 19 days at or above 90 degrees.
Looking ahead to the next 7 days, it definitely looks cooler in the Chippewa Valley, especially, this weekend when highs are expected to be in the 70s only. Next week looks pretty seasonable with temperatures generally in the 80s. By the end of summer last year, we clocked 30 days that were at 90 degrees or higher. I have a feeling we’ll be shy of that number this year.