The potential for large rainfall totals stems from the significant amounts of moisture feeding the storm and from its glacial pace, forecasters say. The storm system is moving at a lethargic 2 miles an hour. (By contrast, hurricane Katia, currently in the Atlantic, is traveling a bit more smartly along its path at some 15 miles an hour.)
Along the Gulf Coast, emergency managers are gearing up for tropical depression 13.
If the storm behaves as currently forecast, it will bring badly needed water to a drought-parched portion of the country.
Along with Texas, Arizona, and New Mexico, Louisiana, Mississippi, and Alabama also are enduring drought conditions that range from severe in eastern Alabama and Southern Mississippi to exceptional in western Louisiana.
Some local officials, however, are concerned about receiving too much of a good thing.
As the Gulf Coast prepares for its first land-falling tropical cyclone, Katia continues to head generally northwest toward the southeastern Atlantic Coast.