From the Spaceflight Meteorology Group:

The National Weather Service has issued a Flash Flood Watch that includes JSC and vicinity until 7AM Sunday morning.

Showers and thunderstorms will be increasing in coverage around JSC this morning.  Rainfall rates of 2 to 3 inches per hour will be possible.  Heaviest rainfall at JSC appears like it will occur Saturday night.  Highest rainfall accumulation through Sunday morning looks like it will be west through north of JSC.  JSC totals should be near 1.5 to 2.0 inches on average with isolated totals up to 3.0 inches, again mainly off to west and north.

Road closures may be found on the TranStar website,