A heavy rain event is expected over parts of Texas, Oklahoma, and Arkansas over the next several days.. Widespread 2- to 4-inch rainfall amounts can be expected with isolated amounts over 5 inches.
Currently, a pool of deep moisture is starting to be pulled on-shore over the Southeast Texas coast. Precipitable Water (PW) is an indication of the total amount of moisture in the atmosphere. PW values above 1.0 inch (high) are just offshore. Low pressure will slowly push northward and pull the moisture into Texas tonight through Wednesday. A combination of a strong upper system, deep moisture, and a surface low will produce the heaviest rainfall over the eastern third of Texas, Northwest Louisiana, Southeast Oklahoma, and much of Arkansas.
Note that there is a significant difference in soil moisture over this region. Most of Texas can receive at least 3 inches of rain before more significant runoff is initiated. Arkansas has been wetter, and runoff could commence earlier, perhaps after a couple of inches of rain.
It is likely that this rain event could significantly reduce, or even eliminate, drought impacts over the eastern third of Texas.