Afternoon weather update

Storm Reports:
2 miles west of Lake Summerset (Stephenson Co.) - Reports of 3 inch diameter limbs down and cornfields flattened
4 miles East of Durand (Winnebago Co.) - Reports of thunderstorm wind damage...large tree limb down - west bound on highway 75 four miles east of Durand
Rockford (Winnebago Co.) reports of flood - 10-12 inches of water over intersection of Court and West State Street in downtown Rockford
Cherry Valley (Winnebago Co.) - Thunderstorm Wind Damage - estimated 65 mph winds brought down large branches

Machesney Park (Winnebago Co.) - amateur radio reports thunderstorm wind damage - 20 to 30 foot/6 inch diameter limb fell through roof of house

Strongest part of the storm is now east of Rockford with heavy rainfall occurring.  A few more storms have developed near Forreston and will continue to move east.  Reports of flooding near Court and West State Street in downtown Rockford along with tree branches/limbs down near Durand and Cherry Valley.  As this storm continues to move east the threat for damaging winds and heavy rainfall remain possible.




Strong storm now moving through the heart of the Rockford metro.  Winds up to 70 mph and torrential rainfall are possible from Beloit southward to just the east of downtown Rockford.

Severe Thunderstorm Warning issued for Winnebago, Boone, Ogle, DeKalb and McHenry counties until 9pm





Reports from the Stephenson county emergency manager of 3 inch diameter limbs down and cornfields flattened near Lake Summerset in Stephenson county.


The Severe Thunderstorm Watch has been extended to 1am for Winnebago, Boone, McHenry, Ogle, Lee and DeKalb counties

Severe Thunderstorm Warning for Stephenson county until 8pm and for Winnebago, Boone and Ogle counties until 8:30pm.  Storms moving out of Green county and into eastern Stephenson county are capable of gusty winds and hail.




The Severe Thunderstorm Warning for Winnebago county has been canceled but continues for Boone county until 7:45pm.  Our eyes now turn to what's happening to the northwest.  The storm in Green county may begin to bow out as it moves northeast.  I wouldn't be surprised if another warning is issued for Winnebago county shortly.



6:35pm: A Severe Thunderstorm Warning has been issued for northeastern Winnebago and northern Boone counties until 7:45pm.  The warned storm is just south of Janesville, WI and slowing shifting east/southeast.  Storm will be capable of producing large hail and strong winds.  Rotation within the storm will also be monitored.

A Severe Thunderstorm Warning is in effect for Green and Rock counties in southern Wisconsin until 6pm.  Thunderstorms have developed north of the stateline and just north of the stationary boundary.   These storms are currently moving to the east only around 10 mph.  The threat, along with wind and hail, will also be very heavy rainfall.



A Severe Thunderstorm Watch has been issued for all counties in northern Illinois and southern Wisconsin until 8pm.


Parts of northern Illinois and southern Wisconsin are currently being monitored for a potential severe thunderstorm watch.  The ongoing storms to the north across Wisconsin and Minnesota have left many outflow boundaries in the Midwest but the one we're most interested in is the cold front/wind shift line that has been in place across northern Illinois all morning.  At 11am this boundary was south of Rockford but with the current sunshine in place and ample amounts of moisture the boundary has lifted a little further to the north. 

Dew points will continue to remain in the upper 60s as well as low 70s this afternoon and with the potential for storms to initiate out west in portions of Iowa and southeastern Minnesota, the instability and energy needed to sustain those storms as they move east will be there.  Right now things are fairly quiet, but as daytime heating continues it's possible storms may begin to develop in northeastern Iowa by the middle of this afternoon.  The Convective Inhibition (known as CIN) isn't fairly strong right now.  CIN is basically a measure of how strong the cap, or lid, on the atmosphere is and is the opposite of CAPE (the energy needed to get storms to form; which we have a lot of right now).  The winds aloft will remain from the west through the evening so any storms that do develop in Iowa would have a better shot of moving into the area.  If storms do initiate out west later today they will likely evolve into a cluster, or line, of storms as they travel east.  This would increase the chance for damaging wind gusts as well as hail.

Northern Illinois and southern Wisconsin have been placed under a slight risk for severe weather for the remainder of this afternoon and evening.  Conditions will continue to be monitored throughout the day with any further updates if needed.  Should any watches/warnings be issued our blog, facebook and twitter will all be updated.  Be sure to keep checking back for the latest updates.