At a Glance

A broad area of low pressure is being watched for possible tropical development in the Bay of Campeche.This system could become a tropical depression near Mexico before it moves inland by tonight, but those odds are decreasing.Moisture from this system will help to fuel heavy rain from Texas to the lower Mississippi Valley.

A swirling area of low pressure in the western Gulf of Mexico is being watched for the possible development of a tropical depression, but no matter whether this system forms or not, it will help fuel heavy rain in parts of the south-central United States.

This system, also known as Invest 91L, is producing moderately intense disorganized showers and thunderstorms over the western Gulf of Mexico. Satellite images do indicate this system has a broad circulation, but it has become less defined over the past day.

(MORE: What Is an Invest?)

The National Hurricane Center has given this system a low chance to briefly develop into a tropical depression by Tuesday night, but odds of this happening continue to decrease.

Even if further development does not occur, heavy rainfall is expected over parts of eastern Mexico, which could result in some flooding.

Moisture from this system will also flow northward and begin to reach southern and eastern Texas later Tuesday into Wednesday, helping to enhance shower and thunderstorm activity there. The tropical moisture could then spread toward the lower Mississippi Valley later in the week as it interacts with an area of low pressure moving through the southern tier of the United States.

This will make conditions favorable for heavy rainfall from eastern Texas into the lower Mississippi Valley, particularly from Wednesday through later this week. Flash flooding will be possible across parts of those regions, including the Houston metro area. For more on that story, .

Be sure to check back to weather.com for updates on this system.