That's why they are urging people to get prepared for the rain now.
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The first tip officials give is to move your car if it's parked in the street.
Our streets are designed to flood when it rains. That's how the water gets out to the bayous. You don't want your car to be a casualty of that.
"But we don't know how long it's going to be over our county or whether it will even make it this way. So we need folks to be aware," said Harris County Judge Lina Hidalgo.
"If you can, get into a parking lot, get your vehicle into a place and just stay there. The water will go down. It may take a few hours," said Harris County Flood Control District Meteorologist, Jeff Lindner.
Counties have also gathered resources for high water rescues.
Between the sheriff's office and fire department in Harris County, there are 20 different kinds of high water vehicles and 39 different kinds of boats.
In Montgomery County, the sheriff's office has four rescue boats.
Fort Bend County has one rescue boat available.
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