Relentless downpours to raise flood risk in south-central US

Repeated rounds of downpours and locally gusty thunderstorms will hammer parts of the Big Bend of the Rio Grande River Valley through southwestern Arkansas into Thursday, threatening several inches of rain and flash flooding dangers.

A general 2-4 inches of rain is forecast, but an AccuWeather Local StormMax™ of 10 inches is predicted from central Texas southwestern Arkansas as a series of weak disturbances rides along a stalled front lingering in the area.

Since much of this region is not currently in a drought or abnormally dry, it may only take an inch or two of rain in a couple of hours to lead to flash flooding of small streams, and any persistent downpour could lead to rapid flooding in urban areas.

Various flood watches, advisories and warnings were in effect on Wednesday afternoon from portions of the southern Plains to the Mississippi Valley.

However, most of the flood watches were allowed to expire early on Thursday morning.

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As we move into the weekend, the bulk of the heaviest rain will move to the southwest including areas near the Big Bend of the Rio Grande Valley to central Texas, including San Antonio.

Those spending time camping in the region, such as in the Ozark Mountains, prior to the Labor Day weekend may need to exercise caution when staying overnight near creeks and small rivers as these waterways could rise several feet without notice due to upstream rainfall.

Pockets of severe thunderstorms can occur on through Thursday from Texas to Tennessee and Kentucky. Some communities in the Ohio Valley, Appalachians and mid-Atlantic region could face their share of heavy, gusty and locally severe storms from mid- to late in the week as well.

Cooler and drier air is forecast to nose southward over the Plains later this week. This will rearrange the wet weather pattern in general, but will end the threat of rain in some locations of the central and southern Plains.

Still, a narrow zone of showers and thunderstorms is likely to persist from parts of central Texas to portions of the Mississippi, Ohio and Tennessee valleys on Friday.

A stronger push of drier and cooler air will arrive across the region by the weekend, suppressing thunderstorms for most areas and confining stormy conditions to parts of central and southern Texas.

Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier and Verizon Fios.