Saint Helena, CA 94574 Weather

Key Messages

Updated at 1202 AM PDT Thu Oct 22 2026

- Rain showers continue through this afternoon

- A warming and drying trend expected for the upcoming weekend into early next week

Short Term

Issued at 1202 AM PDT Thu Oct 22 2026 (Today and tonight)

Primary concern in the short term remains rainfall from the upper level low just offshore of the Central Coast into early this morning. The window for a chance of low-top supercells and the accompanying severe threat has closed with just light rain expected for spots that see any rainfall over the next 24hrs or so. The slow moving upper level system is still expected to produce anywhere from 0.10"-0.50" for most spots over the course of the day today, with coastal areas assisted by upslope flow to see the highest totals. The rainfall on the back side of the system should taper off entirely by sunset tonight and drier conditions filling in amid subsidence on the backside of the exiting wave.

Long Term

Issued at 1202 AM PDT Thu Oct 22 2026 (Friday through Wednesday)

PWATs begin to drop more considerably later in the day and evening Friday indicating further drying conditions and warmer temperatures for the weekend into the beginning of next week. However, temperatures for the weekend into the beginning of the work week will hover right around normal for this time of year, with no big warmup indicated under relatively low amplitude, progressive ridging through the middle of next week when troughing begins to develop well offshore.

Aviation

(12Z TAFS) Issued at 433 AM PDT Thu Oct 22 2026

VFR with temporary drops in visibility and ceiling heights likely as stronger showers move through the Bay Area and Central Coast. More persistent MVFR conditions are expected at LVK this morning where showers are more consistently training over the airport. Showers are likely to continue through late this afternoon with a low potential (10-15%) of thunderstorms this afternoon. This is a more widespread risk compared to yesterday so we will need to keep an eye on the radar/amend if needed this afternoon. Moderate onshore winds are likely this afternoon with winds decreasing tonight into tomorrow morning. Confidence is low on the cloud cover forecast for tonight/tomorrow morning. Current thinking is that MVFR CIGs will become more likely early tomorrow morning after showers end and mid-level clouds start to clear out.

Vicinity of SFO...VFR. Scattered showers will continue to impact SFO through this afternoon with a low potential for thunderstorms. Expect temporary reductions in visibility/ceiling heights and gusty winds if a stronger shower or thunderstorm moves over the airport. Shower activity decreases by late this evening and mid/upper level clouds will start to clear out. MVFR CIGs look likely to develop overnight but confidence is low to moderate in the current CIG forecast.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Showers return by mid to late morning and persist through the rest of the day. There is a low potential for thunderstorms this afternoon/evening which may reach MRY and SNS. Temporary reductions in visibility and ceiling heights are possible if a stronger shower moves over the airports. Shower activity prevails longer over the Central Coast than the Bay Area so have kept vicinity showers in through the overnight hours as guidance shows occasional showers continuing overnight.