An update about our current risk for severe weather is warranted. Earlier a slight risk was in place for the Sauk Valley area across Whiteside and Lee county. At the 11:30AM update, the Storm Prediction Center noticed a quasi-stationary front which extends from central Iowa through northern Illinois onward to Indiana. Due to this and the atmospheric conditions this is causing, the enhanced risk which was located to our north has been significantly dropped south across much of Illinois. This pinpoints Whiteside and Lee county in the cross hairs for redeveloping storms this afternoon and evening rather than late tonight.
The SPC suggests storms will redevelop and intensify along the quasi-stationary boundary and intensify through time. Currently two mesoscale convective vortex are present in South Dakota and Minnesota. These two MCV’s could play a drastic role in today’s storm initiation. Organized storm development will be possible with both supercells and bowing segments. The primary risk remains with wind damage, hail, and heavy rainfall. However, the SPC has introduced a 5% tornado perimeter across our area and parts of Iowa. This is due to hodographs that are showing favorable conditions.
15Z HRRR model run simulates a strong thunderstorm across Whiteside, Lee, Ogle, and Carroll counties at 7PM. Please note this is just a simulated graphic. However, at this time we pinpoint favorable conditions for tornadic development according to our models in Whiteside and Lee county. This does not mean it will occur, but this current hourly model suggests conditions favor it.
Following later, the same 15Z HRRR model suggests a large bowing segment to enter into the area 2-4 hour after the first segment. This will reintroduce risks for damaging winds and heavy rainfall.
Summary
All hazards at this time are possible across the Sauk Valley Area.
Wind Risk: High
Hail Risk: Average
Tornado Risk: Low – likely remain isolated or brief if one occurs.
A watch may be issued later this afternoon due to the conditions and threats this may pose. If any further updates are needed we will warrant them. Again, this is information that was needed to be updated and passed along.
We will continue to monitor this weather situation as it continues to unfold and get closer.
