SIGNS THAT SUMMER HEAT AND STORMS ARE LOOMING

In the short term rather cool conditions will build over the Upper Midwest, however looking towards the middle of June, we are starting to see some sign that summer heat is looming, and that could lead to increased severe weather chances as well. Probabilities for above-normal temperatures based on analogs centered June 15-18 have increased significantly, now well into the 80%+ range. This is one of the strongest signals so far this season.

Since May 1 overall temperatures have averaged near-normal to slightly below normal across the Midwest. Around the Quad Cities the average temperatures have been about 2° below normal.

The European Ensemble shows a big flip of the pattern from early this week heading to the weekend. Strong northwest flow will likely turn to strong ridging over the central CONUS. This also has strong support on the American GEFS product for the same period.

Temperature anomalies on the ensembles at this point are starting to show above-normal trends starting as early as next weekend and early next week. It's not quite strong yet, but at least the trend is starting to show it.

Analogs are also showing some potential for temperatures to reach into the 90s for the Quad Cities region. It's still not too strong, only about 60% probability, but again it's a signal we haven't had much yet this year.

Year to date, the Quad Cities has had a single 90-degree day. May 15 reached 93° which is the warmest day of the year so far. Looking long term this is actually rather close to average, however since 2017 it's a little more rare to have just one. For example 2023 there were nine 90°+ days through June 7 and 2022 had six. The 30-year average (1991-2020) is about two days.

The Climate Prediction Center has outlined the Upper Midwest, especially much of Iowa, at a higher risk of extreme heat June 15-17. I am not sold on the idea of "extreme heat" yet, but it's certainly trending much warmer across the region.

Before the warmer temperatures build in there appears to be an increasing risk of storms and severe weather prior to the pattern flip. Analogs have 80%+ chance of above normal precipitation all around the Great Lakes region June 12-15.

The probabilities of at least one severe weather report across eastern Iowa and northern Illinois is topping 70% during this time period.

Of the 50 members of the European Ensemble about 18 have at least 0.10" of rain around this period. You can somewhat see there is a signal in that window for more active weather with about 11 members having a least 0.50" of rainfall. Need to watch this time frame, again roughly June 12-14, for potential severe weather given a favorable overall pattern.

That'll wrap is up for me today! Last night we had a great launch of a Sirius XM satellite over the Florida Space Coast following some thunderstorms that caused a slight delay to the launch. Always great to see a bunch of people on the beach at 1 a.m. to watch some rockets!

-Meteorologist Nick Stewart