The storms this morning didn't pack much of a punch along the leading edge like thunderstorms typically do. But immediately behind the storms, there was a strong push of Easterly winds called a "wake low". This small-scale area of low pressure can occasionally develop behind an outgoing complex of storms, bringing sharp pressure drops over small areas. Air rushes in to fill the void left behind, causing the strong winds in the wake of those storms.
Weather observer Fred Demeter near Stockton recorded this wake low with a barometer. He measured a drop of 0.3 inches of mercury (7-10 millibars) in barometric pressure in just 10 minutes. That also came with a period of gusty East or Southeast winds, above 50 mph from Fred's measurements.
It wasn't just Stockton that saw the winds either. Much of the area saw at least 40 mph gusts in the wake of those storms. DeKalb, Freeport, and Galena each observed 50+ mph wind gusts. Some scattered tree damage was reported across parts of Rockford with extensive damage in parts of DeKalb and Kane Counties. A 70+ mph wind gust was even reported in Milwaukee with more widespread damage. A wind advisory was issued as this wake low began developing and was upgraded to a high wind warning for DeKalb, McHenry, and Kane Counties once the threat for damaging non-thunderstorm winds was imminent.
While wake lows are not all that common, it is a reminder that strong winds can occur outside of thunderstorms too!
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