UPDATED Thursday December 11, 2014 2:00pm

The National Weather Service in the San Francisco Bay area has extended a Flash Flood Warning that include Napa County until 4:00p.m. and has issued an Urban and Small Stream Flood Advisory in effect until 4:45pm. The Flash Flood Watch for the region will continue through tonight. The sandbag station on First Street at Freeway Drive is closed and the station on Menlo Avenue near Memorial Stadium remains open through tomorrow. Approximately 25,000 sandbags and 400 tons of sand have been distributed since Wednesday morning. 
A Flash Flood Warning means that flooding is occurring or is imminent. Runoff from heavy rainfall will cause localized flooding of small creeks and streams as well as roadways, underpasses and other low lying spots. Do not attempt to cross swiftly flowing water or water of unknown depth. Turn around, don't drown. It is important for campers and hikers to know where they are relative to creeks, streams or rivers which can become dangerous. A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. The Urban and Small Stream Flood Advisory means runoff may cause ponding of water in urban areas, on highways, streets and underpasses as well as other poor drainage areas and low lying spots. Small creeks and streams could flood quickly, possibly covering roads and nearby low areas. Residents are encouraged to monitor later forecasts and be prepared to take action should flash flood warnings be issued. Driving conditions may be very poor at times during this event. Moderate rain is expected to continue for several more hours and lLocal law enforcement reports continued minor roadway flooding concerns. Allow extra time to get to your destination. If water covers the roadway do not cross it. Flood waters are usually deeper than they appear and the water may be too deep to allow your vehicle to cross safely.