INTENSE STORM THREAT
An extremely unstable air mass is situated over the region and will be the focus for intense thunderstorm development late this afternoon and evening. The Storm Prediction Center has issued a level 4 of 5 MODERATE risk outlook for severe storms capable of all modes of severe weather.

Additionally, all of my area is now under a severe thunderstorm watch until 11:00pm

Strong to severe storms are rapidly developing in my western counties that will surge east across the area this evening. Conditions will rapidly change as the storms enter and pass. SPC indicates an 80 percent chance of 10 or more severe wind events. Odds are 70 percent of at least one gust of 74 mph. The watch specifies winds of up to 85 mph are possible in the strongest updrafts.
The derecho composite is very high at 14.

The microburst composite is maxed at 11.

The experimental violent tornado index is at 9 over EC Iowa. While there is a tornado threat, the storms should quickly congeal into a line, meaning most of the tornado threat is QLCS (Quasi-linear in nature). Usually these tornadoes are embedded in the line and are often difficult to see. They are usually quick spin ups with a relatively short lifespan and tend to remain EF2 strength or less. However, they can still be dangerous and cause damage.

By 8-9 this evening, the squall line with its high wind potential is shown advancing out of eastern Iowa into western Illinois.

CAPE values are as high as 7500j/kg which indicates an explosive atmosphere. With the CAP currently breaking, storms are rapidly developing. The potential for damaging winds is significant and this is a situation to take seriously. Get loose items in or secure things that can blow. Along with the wind, intense rainfall of 1–2 inches in an hour is likely in the stronger storms. Keep abreast of warnings. Roll weather...TS
Comments