DAMAGING WIND THREAT...

Intense thunderstorms have erupted (as expected) in the extremely unstable air mass located over the area. SPC has noted a strong rear inflow jet of 85-90 kts near Cedar Rapids. That implies a strengthening trend is likely as the storms move into the SE half of my area through midnight. Winds of 60-80 are quite possible. Some gusts to 100 are not out of the question. Derecho parameters are significant and the rear inflow jet confirms that below.

The storms are rapidly approaching the Quad Cities and points southeast. Bring in the chairs and anything that can be blown around. These are significant storms that can produce power outages and tree damage. Take them seriously. SE Iowa and the area near and east of the Mississippi has the greatest risk of damaging winds going forward.

SPC has upgraded to an enhanced risk of severe weather in EC Iowa and northern Illinois for the next few hours.

Below is the mesoscale discusion from SPC.

DISCUSSION...A cluster of supercells across north-central Iowa has congealed into a bowing segment near Cedar Rapids. A 81 knot wind gust was measured in Marshalltown, Iowa, on the western edge of this cluster. However, a more organized bowing segment on the eastern periphery of this cluster will likely pose the greatest significant wind threat for the next few hours. A 85-90 knot rear inflow jet is being sampled by the KDVN VWP at around 5500-6000 feet west of Cedar Rapids. Expect surface wind gusts of 80+ mph across eastern Iowa over the next 1 to 2 hours as this linear segment accelerates eastward.

Roll Weather....TS