They received a whole month’s worth of rain in just three days.

(CNN) — Dangerous flash flooding occurred in parts of Texas and Louisiana this Wednesday, the result of strong storms to the south.

Several cities in Texas and Louisiana have received more than a month’s worth of rain since Monday. However, some Texas cities have collected nearly twice the usual amount for January over the same period.

Rainfall totals in the College Station, Texas area — about 130 km northwest of Houston — since Monday have reached nearly 15 centimeters since Wednesday morning. The city receives an average of 7 centimeters of rain in January.

West of Houston, Industry and Fayetteville, Texas, received more than 10 inches of rain for the week.

The torrential rains are part of a multi-day flood threat that will reach its most alarming levels in the region this Wednesday.

San Antonio, Beaumont, Texas, and Lake Charles, Louisiana, were among the cities that issued flash flood warnings Wednesday morning.

The National Weather Service issued a “life-threatening flash flood” warning east of San Antonio early Wednesday morning. The area has received 12 to 18 centimeters of rain since Tuesday, with more to come.

A widespread patch of 2 to 4 inches of rain has drenched areas from eastern Texas to Louisiana and southern Arkansas since Tuesday.

Daily waves of warm, moist air will continue to fuel a round of storms that will flood the South by midweek before wet, gray weather sweeps across a wide swath of the eastern United States this Friday and Saturday.

Credit: CNN Weather

Moisture from the northern Gulf of Mexico increases the risk of flooding in the south.

Widespread rainfall of 10 to 15 centimeters is likely across much of the south. The highest totals are likely in areas near the Gulf of Mexico, where several rounds of heavy rain and a few thunderstorms will develop.

Parts of eastern Texas, Louisiana and Mississippi could end the week with nearly a foot of rain.

Rain of this nature can easily cause flooding, especially in drought-prone areas of Louisiana and Mississippi, because the soil is dry and hard, allowing little water to penetrate.

Drought conditions cover more than 80% of Mississippi and more than 90% of Louisiana, and more than 10% of both states are in exceptional drought, the most severe level on the US Drought Monitor scale.

Although the rain will be less intense from this Wednesday, it will continue throughout the week in some southern areas.

For this Friday and Saturday, the scope for rain will expand greatly, bringing gray and wet weather to much of the East.

Around 2 to 5 centimeters of rain is possible during this time across the central Appalachians across New England.

CNN meteorologists Rob Shackelford and Elizabeth Wolff contributed to this report