Flash Flood Warning issued September 15 at 7:45PM CDT until September 15 at 9:00PM CDT by NWS Lubbock TX

Radar and automated rain gauges picked up the heavy rainfall, and forecasters say another half inch is possible before the storms clear out. Streets and highways are already soaked from earlier storms, so the new rain has fewer places to go.

Flash flooding was already underway or expected to start shortly after the warning went out, according to the NWS Lubbock office. The warning covers urban areas along with small creeks, streams, highways and streets, so the danger isn't limited to one side of town.

Underpasses and low-lying streets fill quick when this much rain falls in a short window, and cars stall out or get swept up faster than drivers expect. Anyone heading out before 9 p.m. Should watch for water pooling on the road and avoid driving through it, since it's tough to judge depth in the dark.

Four inches of rain in under an hour is more than some parts of Lubbock see in a typical month.