This Friday the first good punch of fall air is set to dive into the Midwest. It will be a dramatic change with the last 7 days producing a positive temperature departure that looks like this. Summery air dominating the Midwest.
Thursday will be the end of the warmth and it may be the last chance at a 90 degree high for many months to come. We'll give it a run with the EURO showing highs of 85-90 for much of the central Midwest.
Thursday night the tide turns when a potent cold front crosses the central U.S. It will bring the threat of active thunderstorms. By morning the front passes and temperatures hit the skids. Saturday morning high pressure is parked overhead and with light winds and dry air readings tank. Look at all the 30s and 40s.
The NAM is even colder showing a frost potential.
At this point I'm going conservative projecting a high of 90 in Cedar Thursday and a low of 44 Saturday morning. That equates to a 46 degree drop in temperatures in 36 hours. We're going over the cliff and it's going to get your attention.
This sets the area up for a beautiful fall weekend with plenty of sunshine and crisp temperatures. Just what you would expect for the beginning of fall (Saturday evening 8:54 pm).
Also, the trend to cooler weather looks as though it could be an extended one. Even the CFSv2 has this for 10-15 day temperature departures (September 28-October 3).
The GFS for the same period at 5,000 ft.
Now the EURO.
It sure looks to me like the transition is underway to fall. Roll weather...TS