Ok all - here I go out on a limb.
First off, it's remarkable how the weather systems in the forecast the next 9 days miss Iowa. Very little precip for Iowa according to the forecasts. The rest of the Midwest continues with the hit and miss stuff - same as we've had. Days 9-10, August 8 - 9th, is interesting again. It's the same set up we had 4 days ago. At the jet stream level a small high pressure system over the Northwest Territory of Canada feeds into another impressive Low centered South of Thunder Bay, which pushes the jet stream over the center of the US with a west - east flow. This high/low setup pulls air from the artic. Forecast temps in the 30's will be about 200 miles north of the Canadian border over MN. I would not be surprised to see some temps in Northern MN drop into the 30's. But this is only August 9th, with the second nearly identical setup in Canada in two weeks. As the arctic begins to cool, it will allow for less air mass modification before it gets to to US. If this pattern were to repeat three more times on the two week interval, it brings us to the full moon date of Sept 19, which was discussed back a month or so ago. The odds of the setup repeating, I can't answer. I can tell you the next 10 days, it'll be cooler than normal in the Midwest, with a longer duration to come.
In addition to the event on the 8th and 9th, the Gulf is open with a surface high feeding moisture into the Midwest. This will interact with the jet stream and cold air from the north - creating what could be a good rain event. It's all going to depend on the strength of the low as to how far south it pushes the jet stream. Right now, NE & KS (note - not IA), and then, yes again, IN and OH getting up to 2 inch rainfalls over maybe 40%. But, if the low gets larger and pushes the jet stream south, the rain would miss the corn belt. Weaker, and the northern tier gets it. It's really an interesting dance these Lows are doing in Canada - stand by for results.
Jen
