On Wednesday the Houston area has a 100 per cent chance of receiving heavy thunderstorms,  according to weather forecasters.

Such forecasters are accustomed to calculating the weather as percentages and “chances,” but when it’s 100 per cent, then technically that’s not a chance but a certainty.

It will rain Wednesday — perhaps hard. Count on it.

Less certain but strong possibilities are gusty winds and thunder, along with some street flooding. There may even be isolated tornados.

Thunderstorms should reach the Gulf Coast by 2 a.m. Wednesday, while others should hover west of Houston later in the morning. Indeed, a “severe weather outlook” for a 23-county area including Harris County has been issued by the National Weather Service.

How much rain is expected? One to three inches are possible in many areas, and as much as five inches in spots where thunderstorms linger.

Obviously, flooding may be a problem. As always, drivers are advised not to venture out unless necessary, and not to drive into high or rising waters in hopes of passing through.