July 5th: A break from the heat is coming up, but for how long?

HEAT AND HUMIDITY

Whew. We're in the midst of an impressive heat wave gripping the Midwest, but a break is on the way. The actual temperatures have generally remained in the low to mid 90s, but it's been the humidity that has been high to extreme for an extended time. In the summer, we use a dew point of 70 as the benchmark for high humidity. Dating back to the first week of June, there's only been one afternoon with dew points below 70. By Saturday morning, dew points will be back in the 50s for the first time in nearly a month! Enjoy!

Big dome of high pressure responsible for the heat remains in control through Thursday

By Saturday, dome of high pressure is shifted west

RAINFALL

Despite the heat, rainfall has drastically improved over the last two weeks across southern Illinois. A series of gully-washer rains packed with multiple rounds of severe storms have helped many across the region. Looking at southern Illinois in particular, huge improvement is noted across Franklin, Perry, Jefferson, and Wayne counties. One of the driest spots in southern Illinois continues to be Hamilton County, but no one is in drought at this point in the Summer.

Last 60 Days of Rainfall Compared to Normal (Ending Morning of July 5th)

Last 60 Days of Rainfall Compared to Normal (Ending Morning of June 18th)

The question is,  how long does the heat stay away? The upper-level high pressure has been the key for to the heat this Summer. When it goes west, we cool down and also enjoy a more favorable storm track for rainfall. When it shifts east, we get hot and rain chances resort to pop ups. 

LONG RANGE OUTLOOK

The big dome of high pressure will likely remain the key through the rest of the Summer. While it roars back east for the week of July 9th-14th, there are signs it will shift west in the third week of the month allowing a big trough. It spell a more active pattern with better rain chances that needs to be monitored. As for the heat, the trough looks more focused in the Plains, meaning we could be on the warmer side of it. Our expected summer drought has not taken hold as of right now, and I'm not sure I see if through the end of July. Just remember, it's still the first week of July, so we're far from the end of heat and humidity.