What happened with our severe weather; Biggest tornado outbreak in Wisconsin's history

Chicago NWS meteorologist Gino Izzi put together a very nice presentation as to what just exactly happened with the severe weather in our area Sunday.

Click here to listen to his explanation

Meanwhile, Sunday's twisters in Wisconsin will go down as one of the bigger tornado outbreaks in Wisconsin's history during the month of April.  So far, the NWS has confirmed 10 tornadoes.

Click here for the full details

Weather-Related Gas Conservation Tip

There are a number of small ways you can save on gas during this time of rising gas prices. One of them is weather-related. Try filling-up your car early in the morning or during a colder day. Like almost any other fluid, gasoline expands when it's heated. So filling up during the morning -- before the gas has had a chance to heat-up inside those underground storage tanks -- will give you "more bang for your buck."

Pattern Change to Usher in Cooler Weather

The summer-like weather we had this past weekend will likely be a distant memory by next weekend.  A change in the jetstream pattern will allow much cooler air from the north to spill into the northern Plains and Great Lakes likely by Friday and continue into Saturday and Sunday. 

Later this week strong winds within the jetstream will move into the Pacific Northwest.  Out ahead of it high pressure will bring us a couple nice days before an area of low pressure develops, moves just to the south and pulls down cool, canadian air once again.  It's possible that temperatures this weekend may not get out of the middle 40s.  Rain showers will be likely Thursday and then again on Friday but overnight lows could drop below freezing which would give us a chance to see any liquid precipitation possibly change over to a mix of snow and rain! 

Merrill, WI Storm

Fellow meteorologist Chad Franzen from WSAW in Wausau, WI shared this video of the storm as it moved through Merrill, WI Sunday afternoon. Overall, seven tornadoes were reported in Wisconsin yesterday. Towards the end of the video the tornado sirens begin...very eerie feeling!

Mapleton, IA Tornado Video

Video of the tornado that moved into Mapleton, IA this past Saturday

Weather Chat

Sunday Weather Update

We will continue to update this page throughout the day as we receive more information and data.  Please be sure to keep checking back for all the latest information.

10:00 pm Update:  Line of storms now stretch from just east of Janesville southwest through western Winnebago county and back through Ogle and Lee counties.  Frequent lightning, brief heavy downpours, hail and winds will be common.  Once these storms pass this will be it for the evening.

Severe Thunderstorm Warning now for Jo Daviess, Carroll and Stephenson counties until 9:45 pm.  This storm was near Winslow to Savanna.  Cities in its path are: Pearl City, Chadwick, Cedarville, Lanark, Shannon, Freeport, Dakota, Rock City.  Gusty winds and pea sized hail will be possible with these storms.

Severe Thunderstorm Warning for Whiteside until 9:30 pm

7:30 pm Update:  Cold front stretches from just west of Dubuque southwest through eastern Iowa.  There are a few storms that have formed along the front; mainly southwest of the Quad Cities.  There is one cell now moving into parts of Whiteside and Lee counties.  This storm, however, has appeared to weaken some.  We'll continue to watch for the development of those storms that are southwest of the Quad Cities but with the sun ready to set shortly we will likely lose some of our instability, thus reducing the tornado threat. 

Tornado Watch issued for Stephenson, Jo Daviess, Carroll, Whiteside, Winnebago, Boone, McHenry, Ogle, Lee and DeKalb counties until 1am.

3:30 pm Update:  PDS (Particularly Dangerous Situation) Tornado Watch has been issued for almost the entire state of Wisconsin.  This does not include Green, Rock or Walworth counties.  The moderate risk has also been shifted further to the north while the slight risk covers our region.  There are a few storms that are beginning to develop in northeast Iowa and will continue to move northeast into Wisconsin with the very strong southwest upper level winds.  What we'll be watching for is any development southward along or just ahead of the cold front in southern Iowa.  Those storms would hold the best chance of arriving into our area.  Storms will likely hold off until after dinner time. 

1:45 pm Update: Severe weather watch will likely be issued for parts of the area within the next hour or so. Southerly winds continue to pull warm and humid air northward ahead of a cold front that currently stretches through southern Minnesota and central Iowa.  Already starting to see cumulus clouds build out ahead of the front and expect storms to form in east/northeast Iowa and quickly race to the northeast into far northwest Illinois and southern Wisconsin.  Storms will probably form west of the Mississippi River and may move west of Rockford sometime after 5pm.  It looks like the majority of this afternoon will remain dry.

9:30 am Update:  Just as I suspected yesterday, the moderate risk has been shifted to the northwest and now covers almost all of Wisconsin, extreme northwest Illinois, northeast Iowa and eastern Minnesota.

A tornado outbreak occurred in northwest Iowa yesterday closer to the warm front and low pressure system with 27 reports of tornadoes.  Now that low sits in southwest Minnesota with the warm front stretching through southern Minnesota and central Wisconsin.  Temperatures are already rising into low 70s with dew points nearing upper 50s this morning.  Our atmosphere will likely remained capped, meaning warm air aloft will keep air from rising and forming storms, through the early afternoon.  It probably won't be until later in the day when a jet streak arrives, stronger winds within the jetstream, that the cap will weaken.  This looks to be around the Minnesota/northern Iowa border.  Now, because the warm front is already in Wisconsin and the low will be moving into Wisconsin later today that area has the biggest threat for seeing a tornado outbreak. 

Originally, I was a little hesitant on the dry-line/convergence line forming this far east.  And as of this morning I'm having a hard time finding it, but it may show up later.  If it were to have developed it would have been our triggering mechanism for storms.  Also, because the low is further to our northwest and the warm front is north, this is where the greatest directional wind shear will occur - thus the greatest tornado threat.  Storms may actually form along the cold front as it moves east into our region this evening.  Now, I'm not saying our tornado threat is zero because if we do see storms this afternoon they could still turn severe and we would still be looking at the possibility of damaging winds, hail, and an isolated tornado.

We will continue to monitor the evolution of this system and keep you updated throughout the day.  I still want to stress that even though the moderate risk has been shifted further northwest you should still keep tabs on the forecast.