A "fast-moving" low pressure system is developing over the Pacific Northwest and is heading south, forecaster Logan Johnson said today.
The front brings the possibility of the season's first frost in North Bay valleys, where temperatures could drop into low to mid 30s Tuesday through Thursday nights, Johnson said.
Low temperatures in the San Francisco area are expected to be in the upper 40s, with highs in the upper 50s, according to the Weather Service.
There is a slight chance of rain across the Bay Area after midnight tonight, Johnson said.
"Unfortunately for us, there is not a lot a moisture associated with the system," he said.
High elevations in the South Bay have the highest chance of rain, he said.
The Weather Service issued a wind advisory for Sunday night, when gusts could reach 45 mph in higher elevations.
Northwest winds between 15 mph and 25 mph are expected throughout the region tonight and should die down before sunrise on Monday, according to the Weather Service.
