Thursday Heat and Storms

11:30pm Update: Heaviest rainfall is done for the immediate area and the severe threat has ended.  There does remain a Flash Flood Warning for Winnebago and Boone counties until 12:15pm, but most of the water should have gone down with the heavy rain ending. 

There will still be a few showers and couple rumbles of thunder, but nothing we need to worry about for tonight.

(10:16:50 PM) nwsbot: Local Storm Report by NWS DVN: SSE Shannon [Carroll Co, IL] trained spotter reports TSTM WND DMG at 08:50 PM CDT -- tree branches down. time estimated.

(10:17:20 PM) nwsbot: Local Storm Report by NWS DVN: Rock Falls [Whiteside Co, IL] trained spotter reports TSTM WND GST of E55 MPH at 09:30 PM CDT -- estimated 50 to 60 mph wind gusts. power out in rock falls. half inch diameter branches down around town. time estimated.

(9:41:14 PM) nwsbot: Local Storm Report by NWS MKX: Milton [Rock Co, WI] 911 call center reports TSTM WND DMG at 06:20 PM CDT -- numerous trees down throughout the area

(9:27:15 PM) nwsbot: Local Storm Report by NWS DVN: Stockton [Jo Daviess Co, IL] law enforcement reports TSTM WND DMG at 09:10 PM CDT -- trees and power lines down. time estimated.

(9:20:13 PM) nwsbot: Local Storm Report by NWS LOT: Woodstock [Mchenry Co, IL] co-op observer reports HEAVY RAIN of M1.07 INCH at 09:15 PM CDT -- storm total 1.07 inches.

(9:16:08 PM) nwsbot: Local Storm Report by NWS MKX: 7 NW Janesville [Rock Co, WI] trained spotter reports HEAVY RAIN of M2.21 INCH at 08:59 PM CDT -- fell in 2.5 hours

(9:14:41 PM) nwsbot: Local Storm Report by NWS DVN: Lena [Stephenson Co, IL] emergency mngr reports TSTM WND DMG at 08:20 PM CDT -- trees down in the area. time estimated.

(8:54:18 PM) nwsbot: Local Storm Report by NWS MKX: SE Evansville [Rock Co, WI] amateur radio reports HEAVY RAIN of M2.40 INCH at 08:34 PM CDT -- rainfall from 630 to 830 pm

(8:49:39 PM) nwsbot: Local Storm Report by NWS DVN: ESE Dakota [Stephenson Co, IL] trained spotter reports TSTM WND DMG at 08:30 PM CDT -- greater than 2 inch diameter tree limbs down

(8:40:10 PM) nwsbot: Local Storm Report by NWS DVN: Apple River [Jo Daviess Co, IL] law enforcement reports TSTM WND DMG at 08:27 PM CDT -- winds estimated to be 70 mph hit apple river with trees and power lines down. stagecoach trail west of apple river had wires down. also a tree was across the railroad tracks along stagecoach trail.


(8:36:42 PM) nwsbot: Local Storm Report by NWS DVN: 1 ESE Nora [Jo Daviess Co, IL] trained spotter reports TSTM WND DMG at 08:34 PM CDT -- 4 inch diameter tree branch down

8:45pm Update: Severe Thunderstorm Warning continues for Stephenson, Jo Daviess and Carroll counties until 9:15pm and for DeKalb County until 8:45pm.  There have been reports of tree damage across the area, with significant damage over Wisconsin.

However, out threat is now shifting to a flooding threat for Northern Illinois and Southern Wisconsin.  Estimated rainfall totals of up to 2 inches of rain has occurred with possibly another 2 inches of rainfall likely.  Our threat now is transitioning from a wind threat to a flash flooding threat this evening.


6:20pm Update: A Severe Thunderstorm Watch has been issued for all of Northern Illinois until Midnight with incoming thunderstorms moving into Southeast Wisconsin.  Strongest part of the storm, where it's bowing out, will occur over SE Wisconsin and NE Illinois and likely moving more east of Rockford.

However, I can not completely rule out a couple strong wind producing storms over Northern Illinois closer to 8pm/9pm.




High temperatures and high humidity continue Thursday evening following a break in the cloud cover Thursday morning.

Sunshine for the afternoon warmed temperatures into the low to mid 90's, but pushed the heat index above 110 degrees for some in Northern Illinois.  It remains humid late this afternoon and will continue to feel that way through the evening, however, a complex of thunderstorms north of Madison could cool some off briefly tonight.

Let's first talk about the heat.  The Excessive Heat Warning continues for Northern Illinois and Green County in Southern Wisconsin until Friday evening.  A Heat Advisory is in place Rock and Walworth counties until Friday evening in Southeast Wisconsin.   That heat should persist into Friday, pending any additional thunderstorms that may fire up along a cold front Friday afternoon.

But thunderstorms are moving quickly through Central Wisconsin into Southern Wisconsin Thursday evening.

A Severe Thunderstorm Watch is in place until 9pm for Green, Rock and Walworth counties.  Strong/severe storms north of Madison have had a history of producing wind gusts upwards of 70 mph in West-Central Wisconsin earlier this afternoon.  These storms are tracking more southeast than south and will likely move into Southern Wisconsin between 7pm and 8pm, and possibly into Northern/Northeast Illinois by 9pm.

There is enough instability in the atmosphere to help these storms maintain their strength, so I would not be surprised to see a few strong thunderstorms roll through parts of the Stateline later this evening.  Once those pass, we should only have an isolated storm threat during the overnight.