RAIN CHANCES INCREASING? LET'S HOPE SO...
How do you dig out from under a very dry pattern? One of the best ways I know of is to establish a southwest flow. Build a warm ridge in the east and a cold trough in the west and a fight is on somewhere in the Midwest. In other words, if you build it, the rain will come. Here's the ridge trough couplet the EURO constructs Saturday. Could there be hope?
You can see why this increases rain chances by looking at PWATs (precipitable water values). Look how moisture (water vapor) is forced into the nations mid-section by the middle of next week. PWATS are shown greater than 2" in the red shaded areas.
Moisture alone is not going to get the job done. To get rain you need forcing and that comes in the form of a front or boundary that sits between the warmth of the ridge and the coolness of the trough. By September 21st the GFS shows rain lined up along such a boundary from Canada to Texas. If the pattern can lock in for a week or more, multiple rain events are possible.
While there is a chance of rain in in the central Midwest Saturday night/early Sunday I don't expect that event to amount to much. However, I think the trough/ridge set-up is likely to hold much of the next 2 weeks so as moisture deepens rainfall prospects should go up towards the middle or end of next week.
Most of the long range models are starting to see the trend and that's reflected in these improving rainfall forecasts. Take a look.
The EURO EPS mean 10 day rainfall forecast.
The CFSv2 10 day rainfall forecast.
Here's the 6-10 day rainfall probability outlook from the Climate Prediction Center