A STORMY PATTERN TAKES OVER

A stubborn Omega Block is breaking down and ushering in a much more active pattern across the region over the next week with some healthy rainfall totals in the forecast, as well as a few chances of severe weather we will have to contend with. The Weather Prediction Center official rainfall forecast over the next seven days (above) has a widespread area of 2-3" of rain.

BOTTOM LINE UP FRONT - Storm chances are likely Sunday and Monday afternoons, and a severe weather risk is setting up over the area Wednesday and Thursday.

Widely scattered thunderstorms are likely Sunday across the region. These will be somewhat hit and miss, so while not everyone will see rain there should be a pretty good amount of rain for most. The HRRR takes this activity through the area in the afternoon and evening hours. Severe weather is not likely with this activity on Sunday.

Another round of widely scattered showers and storms will be likely on Monday as well, especially in the afternoon and evening hours. Similarly, not everyone will see heavy rain but there will be a pretty good chance across our area from east of I-35 in eastern Iowa and across northern Illinois. Severe weather is once again not likely with this rainfall.

Tuesday we may have a break from organized storms over the area with the next chance coming late-day Wednesday as organized storms, likely severe, form to the west and move into our area. This is likely the best chance for seeing severe weather locally in the short term and it could be rather potent. An organized line of damaging wind is most likely at this point in time, however supercells with tornadoes may be the initial hazard as storms first form in the afternoon.

A rather large amount of instability will be in place across the region Wednesday with MLCAPE in excess of 3,000j/kg. Wind shear is forecast to be on the higher side for June, however it looks more unidirectional, meaning winds vertically are generally blowing from the same direction. This would mainly support a damaging wind threat instead of a tornado threat, especially across Iowa and Illinois. This will be monitored as we get the higher resolution modeling in range.

A Level 3 of 5 Risk, an Enhanced Risk, is in place across portions of Minnesota, Iowa and Wisconsin Wednesday. Based on the model data I am looking at I would not be surprised to see that Enhanced Risk area dip farther south into more of eastern Iowa and northwest Illinois.

Thursday we will have yet another risk for thunderstorms, some severe, before the pattern takes a bit of a break behind a clearing cold front. Storms look to form over eastern Iowa/northwest Illinois and track eastward. This time we will likely have the initial storm development over us. Once again, wind shear for this time of year will be on the higher side with adequate instability, so damaging wind gusts, large hail and tornadoes will be on the menu.

The GFS does bring in 2000+j/kg of MLCAPE into the region with slightly better directional wind shear locally.

A Level 2 of 5 Risk, a Slight Risk, is already in place for Thursday. This seems sifficient given questions with instability and previous day storms potentially impacting where the highest severe risk will develop. This has a pretty high chance to change in look, and severe category, in the days ahead.

Bottomline, both Wednesday and Thursday have that look for potential severe weather with damaging wind gusts, large hail and tornadoes a possibility. We will get some beneficial rainfall at least, which is good news this time of year.

Rapid drought development has started across the region with Moderate Drought, D1 conditions, across northern Illinois. Abnormally dry conditions have taken over much of Iowa and west-central Illinois due to this stretch of quiet weather. We need the rain, hopefully we can dodge the severe weather along the way.

-Meteorologist Nick Stewart