2:15 p.m. update: The National Weather Service has extended the flood threat into the afternoon by issuing a new flood advisory through 4:15 p.m. for parts of Brazos, Burleson, Grimes, Montgomery, Walker and Washington counties. Additional rainfall of 1 to 3 inches is possible in areas that have already picked up 1 to 2 inches of rain, raising the risk of minor flooding where repeated downpours occur.
Heavy rainfall is already causing minor flooding across parts of the Houston area, and another round of thunderstorms developing west of the city could prolong the flood threat into the afternoon.
A flood advisory remains in effect until 2:15 p.m. for parts of Harris and Montgomery counties as repeated downpours continue to move across the region.
According to the National Weather Service, radar estimates indicate an inch to 2 inches of rain have already fallen in portions of the advisory area, with another inch to 2 inches possible this afternoon. That additional rainfall could quickly overwhelm storm drains, leading to street flooding in low-lying and poor-drainage areas.
Thunderstorms have been producing intense rainfall across portions of Harris and Montgomery counties since around midday, leading to areas of minor flooding.
More heavy rainfall over already saturated areas will likely lead to continued pooling of water on roads and minor flooding through the early afternoon.
The greatest flooding concern will be in locations that receive repeated rounds of heavy rain, especially where storms move over the same neighborhoods.
At 12:30 p.m., thunderstorms stretched roughly along the Interstate 45 corridor from northern Harris County southward to the Gulf Coast.
Another line of storms was organizing west of Houston from near Sugar Land north toward Hempstead in Waller County. That activity should reach the Houston area between 1 and 3 p.m., bringing another round of heavy rainfall.
Drivers should use extra caution during the heaviest downpours and never attempt to drive through flooded streets, where water depth can be difficult to judge.
Rainfall rates can quickly make normally passable streets impassable, particularly in low-lying areas and underpasses.
If you encounter a flooded roadway, turn around and find an alternate route. Most flood-related deaths occur in vehicles.