Severe Weather Outbreak Possible this Weekend

2:30 pm Update:  Just finished conference call with the NWS in Chicago and the going forecast looks to still be on track.  A very strong storm system continues to move into the southwest U.S. and will push east by the end of this weekend.  A few storms will be likely Saturday night maybe early into Sunday as the front lifts northward, but as was mentioned earlier it appears most of the activity into Sunday morning may actually remain in southern Wisconsin.  The warm front will be north of us by Sunday capping the environment during the afternoon.  It will more than likely even feel a little humid during the day on Sunday.  Now should the cap weaken some during the late afternoon/evening we could actually get a few storms to fire during that time.  However, the main threat does appear to be in the late evening and overnight hours with damaging, straight-line winds.  Although a tornado can't be ruled out.  We typically tend to think of the severe weather threat to diminsh as the night goes on, but because this system will be so strong and we will have built up a lot of energy throughout the day it will likely sustain itself through the overnight.  Even though it is still a few days away, it is a very good idea to get a NOAA weather radio if you haven't done so already.  Because if in fact these storms do come at night the weather radio will alert you!!  There are still some things that can change with this system and we will continue to monitor its progression throughout the weekend, but just to put this into perspective it is somewhat rare to see the Storm Prediction Center highlight a moderate risk 3 days in advance.  Just something to think about.  Be sure to keep checking back for the latest information. 

9:30 am Update: As we've been talking about all week long, the potential does exists for a possible severe weather outbreak somewhere across the Midwest and Great Lakes, especially on Sunday.

A very strong trough is currently moving through the southwestern parts of the U.S. this morning with little disturbances rotating around the base and moving into the Plains and Midwest.  A stationary boundary to the south today will be the focus for storms stretching through southern Missouri/Illinois/Indiana/Kentucky and Ohio.  That boundary will then lift northward through the afternoon on Saturday as a surface low begins to develop.  We may get a few isolated showers/storms during the afternoon hours on Saturday as the front moves closer but it looks like our severe weather will come in two rounds.

The first round will likely be Saturday night into Sunday morning as the warm front pulls through where wind and hail would be the primary threats.  Further to the west across Minnesota and into southwestern Wisconsin there may also be a slight tornado threat.  Once that front passes through, the environment will likely become capped (meaning warm air aloft) and hold our storm threat until late afternoon/evening and into the early overnight.  The low pressure system will pull to our northwest by Sunday afternoon dragging a cold front through Iowa during the afternoon and then into the Stateline overnight.  The timing of the cold front has slowed down some over the past couple of days which may keep some of our severe weather at bay, just like last Sunday.  However, a dry line/trough will move through ahead of the front which should help ignite storms to our west out in Iowa.  There, the potential will exist for supercell storms with the likelihood of tornadoes as the environment would have a lot more shear with it.  As the storms move east they could very well turn from individual storms to linear storms which would reduce the tornado threat but increase the threat for damaging winds by the time the storms arrive late evening.

As of Friday morning there is a slight risk just stretching through north-central Illinois/south-central Wisconsin and back southwest for Saturday.  Sunday's outlook already has highlighted a moderate risk for central and eastern Iowa, northwest Illinois and west-central Wisconsin.  This could be where some of the most significant weather moves through.  Now keep in mind that this is still 2-3 days out and it could very well change.  But please make sure you have some type of action plan in place for this weekend should we see some type of severe weather outbreak.  As was noted by one meteorologist with the NWS in Milwaukee "Situations like this in April tend to result in widespread, significant severe weather episodes including tornado outbreaks through the Great Lakes and Mississippi River Valley".