May 24th: Scattered Storms Return, Watching Tropics for Local Impacts

Here at the station, we recorded rain every day between May 15th-21st accounting for about two-thirds of the rain for the month thus far. The pattern through May has been very summer-like with storms that are spotty combined with a lot of warmth this early in the season, a big change from the record cold April.

The first 23 days of May are in the top 3 warmest starts to the month on record

Just across southern Illinois, the difference in rainfall over the last 30 days ranges from 5"+ from Jackson, Union, and Johnson counties, to less than 1" in Wayne County. Rainfall this time of year can be a key for gardeners and farmers, especially later in the summer when the hot and dry kicks on.

Estimated rainfall between April 23rd and May 23rd

LOOKING AHEAD

The brief dry pattern starts to break down on Friday (May 25th) as the upper-level ridge starts to break down and shifts east. That signals the return of the daily isolated to scattered storms with a fast moving pattern that features waves moving through the Upper-Midwest. Pinpointing when and where storms fire has proven to be a challenge in this setup. 

Memorial Day Weekend Pattern Overview

Beyond the weekend, we're keeping an eye on a system in the Caribbean that is expected to move into the Gulf of Mexico later this weekend. It's a system we need to watch for potential local impacts related to rainfall towards the middle of the next week (May 30th). 

A couple different scenarios related too this tropical system that could play out: 

1) System moves on the coast near Louisiana/Mississippi/Alabama and moves north, pushing moisture into the Lower Ohio Valley and delivering heavy rain to parts of southern Illinois. 

Model signaling tropical moisture (red) moving up the Mississippi Valley

2) System moves into the Southeast, setting up a blocking pattern over the middle of the country with moisture streaming into the Tennessee Valley (Tennessee & central Kentucky), while southern Illinois remains dry. 

Tropical systems are always a wildcard in forecasts and with this one being the first of the year in the Gulf, it's one we'll keep an eye on.