UPDATED 4:15pm Wednesday December 10, 2014 

The Flash Flood Watch issued by the National Weather Service goes into effect at 9:00 p.m. this evening and continues through late Thursday night. A High Wind Warning is in effect from 10:00 p.m. tonight through 10:00 p.m. Thursday. The latest forecast indicates that the Napa area may experience the heaviest rainfall between 4:00 a.m. and 7:00 a.m. Thursday, December 11, with up to one inch per hour possible. Total rainfall in the North Bay may reach 5 to 7 inches with up to 10 inches in the higher elevations. The Napa River is expected to rise to the monitor stage if the predicted amounts of rain occur. Milliken Reservoir and Lake Hennessy are not full and spilling at this time.

A Flash Flood Watch means that conditions may develop that lead to flash flooding. Excessive runoff from heavy rainfall will cause elevated levels on small creeks and streams and ponding of water in urban areas, on highways, streets and underpasses as well as other poor drainage areas and low lying spots. Winds are expected to increase this evening with the strongest winds expected overnight. Winds of 25 to 35 mph with local gusts over 50 mph for urban locations are possible, along with winds of 30 to 50 mph with local gusts greater than 80 mph for higher elevations. These winds may cause downed trees, falling power lines, property damage and difficult driving conditions.

Beginning at 8:30 a.m. Tuesday, the City of Napa made self-serve sandbags available to those who want to take precautions. As of 3pm today, two sandbag stations are in operation: (1) In the parking lot near First Street and Freeway Drive. (2) On Menlo Avenue adjacent to Memorial Stadium. As of 7:00 a.m. today, 110 tons of sand and 9,000 bags have been distributed. Sandbags will remain available as long as there is a need. Residents should bring a shovel and gloves and plan to fill and transport their own bags.

All drainage ditches and channels were inspected and cleaned last week. Leaf pickup was increased to diminish clogged storm drain problems. Stream gauges have been checked, and the weather monitoring center is staffed.

For public safety, Trancas Crossing Park is now closed through the weekend, and the Oxbow Preserve will be closed Thursday and Friday. The gangway for the Main Street Boat Dock will be hoisted out of the floodway today, and the dock will be closed until the storm passes and water levels subside.

City and County personnel will continue to monitor the weather forecast and make all necessary preparations. All residents are encouraged to evaluate emergency plans and supplies in advance of the storm. Visit PG&E's Storm, Outages and Safety page for preparedness information.