A prolonged heavy rain event is expected to unfold across a large portion of the central United States this weekend, with areas from Kansas to Kentucky facing the potential for up to seven inches of rain by early next week. The rain will do wonders to quench drought-bound soils in the region.

The Setup

A stationary front—a boundary between two air masses that barely moves one way or the other—is setting up across the middle of the United States this afternoon, and this front will serve as the focus for the development of some very heavy rain between tonight and early next week.

The convergence of winds along the front combined with downright icky (technical term) dew points and ample atmospheric moisture will create a situation that sees widespread showers and thunderstorms across numerous states over the next four days.

Towards the end of the weekend, a low pressure system will develop along the stationary front and begin moving towards the north; the low's associated cold and warm fronts will spread beneficial rainfall east towards the Mid-Atlantic and Northeast early next week.

How Much Rain Are We Talking?

The above map shows predicted rainfall through Saturday evening, showing a bullseye of heavy rain across southwestern Missouri over the next two days. (The map is a mosaic of local NWS office forecasts, and forecasters don't always agree with one another, so this accounts for the "glitchy" gradient shading along office boundaries.)

A few more inches of rain could fall Sunday and beyond, leading a huge area of the country experiencing heavy rain:

Based on current models, the Weather Prediction Center expects a wide swath of rainfall totals on the order of six to seven (or even more) inches of rain from the Ozarks east through the western Ohio River Valley. The greatest impact is likely to occur right along the stationary front, with cities such as Joplin, Springfield (MO), Paducah, and Evansville potentially winning the rain game.

Drought Relief

Many areas forecast to receive heavy rain over the next couple of days are experiencing "abnormally dry" (on their way to a drought) to "moderate drought" conditions according to this morning's U.S. Drought Monitor update. If the rainfall totals come to fruition, it will help to put a huge dent in the low-grade drought, potentially ending it in some locations.

It's worth noting that a storm system moving into the Pacific Northwest will also provide some much-needed rainfall to areas from extreme northwestern California north through Washington.

Flash Flooding

The Weather Prediction Center has areas from Wichita Falls to the Mississippi River highlighted under a slight risk for excessive rainfall that could produce flash flooding tomorrow. The latest flash flood guidance shows that it'll take between two and three inches of rain falling over a three-hour period to produce flash flooding.

While the threat of flash flooding is no laughing matter, the gloomy weather pattern over the next couple of days will provide much-needed water to areas that haven't seen much of it lately.

Now, if only we could figure out how to send some of it to California...

[Images: Google Earth, WPC, NWS, WPC, U.S. Drought Monitor, WPC]

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