Jul 16 | Climate Review and Weather Update
by Trent Ford, State Climatologist
ISWS PRI University of Illinois
Temperatures moderated a little this week as wind patterns shifted. Average temperatures were in the mid-70s statewide, 2 to 4 degrees above average in northern Illinois, and right at the average in southern Illinois. High temperatures regularly reached into the upper 80s and low 90s, with a few places pushing over the 95-degree mark including 96 in Chicago and Quincy. The first half of July was 2 to 4 degrees warmer than average statewide, with the largest departures in Chicagoland.
While the northern half of the state dried out under a strong ridge, several rounds of storms sneaked past the southern half of the state, in some cases bringing torrential rains and significant flooding. 7-day precipitation totals ranged from virtually nothing in north-central Illinois to over 8 inches in some parts of Jackson and Johnson Counties in southern Illinois. Carbondale picked up just over 9 inches of rain in the past 7 days, making it the wettest week there since May of 2017.
While the southern Midwest has received an abundance of precipitation lately, the upper Midwest has stayed very dry, which has intensified wildfires burning in northern Minnesota and southern Ontario. Northwesterly winds blew in wildfire smoke and created very poor air quality issues from Minnesota to Maine this week. Air quality monitors in Chicago reached an Air Quality Index value of over 700, which is more than twice the threshold for what the EPA considers hazardous. Most of the wildfire smoke and air quality issues stayed in northern Illinois; however, folks statewide should regularly check the air quality conditions over the next few weeks to keep themselves safe from some very poor air quality.
Looking ahead, the ridge in the central U.S. will keep rainfall to a minimum, as most of the state is expected to get less than a quarter of an inch. High temperatures will keep pushing into the 90s this weekend and into early next week, but we will likely see a little break on the back of a weak cold front sometime late next week. We’ll need to watch the wildfire smoke potential brought in by the northerly winds expected behind the cold front next week, as fires continue to burn in Canada.