The National Weather Service in San Francisco has released an update on the local weather conditions, indicating a transition towards drier and slightly warmer weather as we head into the weekend. According to the latest report, today marks the beginning of a switch from the grip of a positively tilted upper trough to a ridge pattern, likely leading to a 5-10 degree rise in temperatures across the region. The marine layer shows signs of return, with a depth of around 1500 feet, suggesting potential cloud coverage along the coast throughout the day.
There's also an eye on potential wildfire smoke, not from nearby Garnet Fire as one might expect, but from blazes in Washington State, as per the NWS update, "some upper level haze" is expected, although no ground-level smoke is anticipated. The marine layer is expected to deepen overnight, ushering in more robust humidity recovery, which bodes well for combating dry conditions, despite moderate humidity recovery forecasted for the highest peaks above 3-4k feet, which also will be in an active thermal belt.
Moving into the weekend, forecasters are predicting even warmer and drier conditions with Saturday's shortwave ridge bringing temperatures that could hit the 90s inland; meanwhile, coastal areas should remain in the more temperate 60s and 70s. Although initially, there were chances of showers in the northern regions on Sunday, "the 00z runs have all but erased it," the NWS update stated, which suggests that precipitation appears unlikely for the Bay Area over the weekend.
Next week, an upper-level ridge is expected to increase temperatures, with interior locales potentially experiencing highs of 95-100 degrees. "HeatRisk values away from the coast do surge into the Moderate category with a few pixels of Major," the NWS San Francisco warns, indicating heightened heat-related risks. However, those near the coast will be spared the worst heat thanks to persistent onshore flow and marine influences. By Thursday, there could be a stir in the weather pattern with a possible influx of tropical or monsoonal moisture.
As for San Francisco's flyers and sailors, the NWS San Francisco forecasts a mix of IFR-MVFR ceilings this morning with anticipated clearings by mid to late morning, except for Half Moon Bay, which could see persistent stratus. Moderate confidence is placed on the marine layer's push back ashore this evening, primarily affecting ceiling visibility for aviators. The marine advisory warns of breezy northwest winds and choppy seas, especially along the Big Sur coastline. Boaters should anticipate "another round of widespread fresh to strong NW winds" starting Sunday, continuing into next week.
