July is in the books, but heat & humidity set to make a return

A LOOK BACK AT JULY 2018

Many will remember July for the heat, but also the humidity through the first half of the month. 14 of the first 20 days of the month had afternoon temperatures in the 90s with heat index values often well into the triple digits. The heat and the humidity was consistent with isolated storms on a daily basis. Miss out on those storms, and it was tough to find much relief. The pattern shift in the last 10 days allowed for a welcomed break and beneficial rains through the last few days of the month. The two hottest days of July came back in the 4th and 5th with 94º and 95º respectively. The two coolest days came the last two days of the month with 75º on the 30th and 81º on the 31st. The last ten days of the month didn't feature a single 90º reading which helped bring the overall month much closer to average.

July 2018 at WSIL-TV (Carterville, Illinois)

Rainfall through the month was generally reliant on spotty storms, but the last few days of the month brought beneficial rains to much of southern Illinois. It didn't make up for the lack of rain through the first 29 days, but Jefferson, Franklin, Jackson, Williamson, and Union counties did quite well.

Rainfall estimates based on radar July 29th - July 31st

LOOKING AHEAD

While I suspect the break from the heat has been welcomed for most, there's still a lot of Summer left. The pattern is already looking to change and usher in more seasonable warmth, at the very least. Ridge of high pressure over the Atlantic will expand westward and kick the heat up a notch into the weekend. 

High pressure along the East Coast shifts westward through the weekend

Looking into the first full week of August, the big persistent ridge in the West remains strong while the high pressure along the East Coast gets shoved into the Caribbean. Cooler air will spill into the Northeast, but Mid-Mississippi Valley (and southern Illinois) will be firmly in the "battle zone" between that cool air to the east and big time heat in the west. The heat and humidity will generally win out in this scenario, but upper-level waves moving from the northwest to the southeast will kick off better chances for scattered storms almost daily. 

Northwest flow overhead will bring better chances for storms into the Mid-Mississippi Valley

SUMMMARY

Heat turns up for the weekend, but an active pattern overall will bring more storm chances next week.