One-time Tropical Storm Imelda, already hitting the Houston area with heavy rain, is threatening to dump up to 18 inches in parts of Southeast Texas and southwestern Louisiana over the next few days.
NOAA's Weather Prediction Center said that as of 5 a.m. EDT Wednesday, the tropical depression's core was some 25 miles north-northwest of Houston and 65 miles southeast of College Station, Texas, moving north at 5 mph with maximum sustained winds of 30 mph.
Imelda is expected to produce 6 to 12 inches of rain with isolated maximum amounts of a foot-and-a-half across portions of eastern Texas, including the Houston and Galveston areas, the center added.
Jeff Lindner, a meteorologist and director of flood operations for the Harris County Flood Control District in Houston, said the main threat from Imelda remained the potential for heavy rainfall and flooding.
"We have a few things in our favor. The ground is dry. It's been dry for a while here as we've come through summer," Lindner said. "The initial parts of this rainfall will go toward saturating the ground."
Ken Graham, director of the National Hurricane Center, said the Houston area and parts of the upper Texas coast and East Texas could get significant rainfall through Thursday as the storm moves north. Imelda's rain bands were also stretching into Louisiana.
The weather center said flash flood watches were in effect for Southeast Texas and extreme southwest Louisiana, though additional weakening was forecast for the next two days.
CBS Houston affiliate KHOU-TV reported some of the areas of heaviest rainfall were still sitting over the coastline and in the Gulf of Mexico Wednesday morning.
While there could be some isolated structure flooding in the Houston area, widespread house flooding from Imelda "doesn't look likely at this point," Lindner said.
However, he said residents who live in flood prone areas should still be mindful and take extra precautions.
Officials in the Houston area were preparing high-water vehicles and staging rescue boats Tuesday.
At of early Wednesday morning, there were no widespread reports of high water on freeways or in structures, KHOU said.
The Galveston school district was those that canceled Wednesday classes, the station noted.
Imelda is the first named storm to impact the Houston area since Hurricane Harvey, according to the National Weather Service. Harvey dumped nearly 50 inches of rain on parts of the flood prone-city in August 2017, flooding more than 150,000 homes in the Houston area and causing an estimated $125 billion in damage in Texas.
The system, which formed Tuesday, quickly made landfall as a tropical storm near Freeport, Texas, with maximum sustained winds of 40 mph, then weakened just as quickly to a tropical depression. Some parts of Harris County and neighboring Galveston County had already received about 4 inches of rain through Tuesday afternoon.