Dangerous flash flooding is ongoing across parts of Texas, Louisiana and Mississippi Wednesday as drenching storms deluge the South.

More than a month’s worth of rain has fallen in several Texas and Louisiana cities since Monday. But a few Texas cities have picked up nearly double what’s typical for January in the same timeframe.

Rainfall totals by Wednesday morning neared 6 inches in the College Station, Texas, area – about 80 miles northwest of Houston – since Monday. The city picks up around 3 inches of rain on average in January.

The week’s rainfall eclipsed 10 inches west of Houston, in Industry and Fayetteville, Texas.

The torrential rainfall is part of a multi-day flood threat that began Monday and is reaching its peak intensity Wednesday.

The National Weather Service warned of “life-threatening flash flooding” east of San Antonio Wednesday morning. Between 5 and 7 inches of rain have fallen in this area since Tuesday, with more to come.

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

The area of greatest concern for flash flooding will center over parts of Louisiana and Mississippi through Wednesday night. A Level 3 out of 4 risk for excessive rainfall is in place for these areas Wednesday.

New Orleans is under this increased risk level, with the heaviest rain expected for the city through Wednesday evening.

Moisture surging north from the Gulf of Mexico is driving the flood threat across the South.

Widespread rainfall totals of 4 to 6 inches are likely across much of the South this week. Higher totals will remain confined to areas closer to the Gulf of Mexico where multiple rounds of heavy rain and a few thunderstorms unfold.

Parts of eastern Texas, Louisiana and Mississippi could end the week with close to a foot of rainfall.

Rainfall of this nature can easily lead to flash flooding, especially in drought-stricken areas of Louisiana and Mississippi, because the ground is dry and hard, allowing less water to soak into the soil.

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

While the rain will become less intense after Wednesday, steady rounds of rain will persist for the entire week across parts of the South.

Rain and will expand tremendously in scope Thursday through Saturday, bringing dreary, wet weather across much of the East.

Around 1 to 2 inches of rain is possible during this time from the central Appalachians through New England.

CNN Meteorologist Rob Shackelford and CNN’s Elizabeth Wolfe contributed to this report.