Short-term drought conditions have developed for a portion of northern Illinois, impacting Ogle, Lee, DeKalb, and McHenry counties. The latest drought monitor released from the National Drought Mitigation Center highlights a portion of north-central and northeast Illinois as ‘abnormally dry’, with much of central and western Illinois also drier than normal. It’s been a week since our last measurable rainfall, and even then, the rainfall totals were under a couple tenths of an inch.
The warm, summer-like, temperatures combined with sunny skies and low relative humidity values have really depleted the soil moisture across north-central and northeast Illinois, but also across much of central Illinois. As of Thursday, almost 48 percent of the state was considered abnormally dry, with just a little over two percent under moderate drought conditions.
A blocking pattern in the jet stream through the weekend will keep high pressure centered over the Great Lakes and Northeast, while moisture continues to move in across the Southeast. As the blocking pattern breaks down, the jet stream will be pulled north holding on to the well above normal temperatures through the middle of end of next week.
Highs over the weekend will warm into the upper 70s and low 80s, with mid 80s expected Memorial Day. The heat will build even further next week as temperatures reach the upper 80s and potentially low 90s. Rain chances look to remain few and far between, but daytime heating beginning Tuesday could lead to isolated afternoon thunderstorms Tuesday, Wednesday, and Thursday.
A cold front moving down the Great Lakes next Friday – a week from today – appears to bring us a slightly higher chance for precipitation. But even that doesn’t look to be significant. During the spring and summer months we typically need an inch of rainfall per week. So far for the month of May rainfall totals have been well below that average, with the month picking up just under two inches. This will cause the deficit of 1.33 inches to continue to grow. Longer range outlooks continue to show slightly higher probabilities for below average precipitation leading into the month of June.