Beginning Thursday night the central Midwest enters into a pattern that promises to bring a nasty brand of weekend weather. By nasty, I mean wet, breezy and chilly. It will be a dramatic change in a month that has already seen seven 80 degree days here in Cedar Rapids.
The big driver in the change will be a Lake Michigan enhanced front that lays out from northern Missouri to central Illinois. North of it brisk east winds will draw in a pool of late season cold air. South of it a summery air mass with highs in the 80s will remain locked in place. Over time, the cool air will find its way south.
You can watch the progression of the chill as it sags into the Midwest over the next 3 days. Here's the 1:00 pm temperatures forecast by the GFS.
Most of my area will be in the chilly air by Friday and the entire region will feel it Saturday. The next issue will be rain. Multiple upper air disturbances will travel along the front triggering bouts of showers with some embedded thunderstorms. The heavier totals will fall north of the boundary where warm moist air is lifted over the cool dense air to the north. The over-running that develops is known to be a classic heavy producer. The position of the front will be a key player in where the heaviest rain bands set up.
The GFS shows this for total rainfall.
The Weather Prediction Center has this for the same period.
Adding to the misery will be the brisk east winds that blow the fresh air in. Speeds of 10-25 mph combined with occasional rain, drizzle, and temperatures in the 40s and 50s will be hard to swallow.
On a positive note, most of the rain should depart by mid-day Mother's Day. Sunshine looks limited but there may be enough breaks to get highs back in the 60s. Beyond that, 80s are back in the forecast by Tuesday of next week. Just a little bump in the road. Roll weather...TS