SAN FRANCISCO (KRON) -- Following lighter rain overnight Wednesday into Thursday, a heavier storm system is due to arrive in the Bay Area Friday. While Thursday's system saw light and scattered showers, more intense rainfall that could bring flooding concerns across the North Bay is expected Friday into Saturday, according to the National Weather Service. San Francisco Bay Area Forecast A flood watch has been issued for the North Bay, beginning at 2 p.m. Friday and lasting until 4 p.m. Sunday. The NWS is warning of possible ponding on roadways and low-lying areas, rising creeks, rivers and streams, and flooding of creeks and streams in urban areas. Follow our Bay Area storm blog for the latest updates