(11:30PM – Thursday, May 15th, 2025) Thursday night update on storm system and a few disturbances that will continue to move through the region, bringing an additional round of rain and t’storm activity or so to the state, from this tonight through Friday night. Severe t’storms will be likely with some of this activity, with significant severe weather expected.
Timing & Location…
•Thursday Night – Friday Morning, May 15-16th: Much of Illinois.
•Friday Morning – Friday Night, May 16th: Large portion of Illinois.
Impacts…
•A level 1 severe t’storm threat is in place across much far Southern Illinois, for the threat of isolated severe t’storms. A level 1 severe t’storm threat is in place across much far Southern Illinois, for the threat of isolated severe t’storms.
•A level 1 to 3 severe t’storm threat is in place across much of Illinois, for the threat of isolated to scattered severe t’storms. All modes of severe weather will be possible with any severe t’storm activity, including large hail, damaging winds, and a couple of tornadoes. Environmental conditions will be supportive of the possibility of occurrences of strong tornadoes, damaging winds 75MPH+, corridors of widespread/significant wind damage, and hail larger than 2.00”.
Update…
•With this update, we have adjusted the severe t’storm forecast for tonight and Friday morning based on real time observations and trends.
•With this update, little change was needed on the severe t’storm forecast for Friday and Friday night, as the going forecast is on track.
Discussion…
•Thursday Night – Friday Morning, May 15-16th: A dry line will continue to be in the vicinity of Southern Illinois tonight into Friday morning. This will be the focal point for the potentially of additional isolated to scattered shower and t’storm activity during this timeframe across far Southern Illinois. Environmental conditions will be supportive of an isolated severe t’storm threat with activity.
•Friday Morning – Friday Night, May 16th: With the main storm system still in the region and the next main disturbance set to move through, a round of showers and t’storms will develop across Missouri and Central/Southern Illinois on Friday afternoon…potentially as far north as Northern Illinois. This activity will be mixed mode, supercells and line segments. This activity will track east and northeast across much of Central and Southern Illinois (And potentially portions of Northern Illinois), from Friday afternoon through Friday night. Environmental conditions will be supportive of numerous severe t’storms across the main threat area, with all modes of severe weather being possible. Occurrences of significant severe weather will be likely as well.
