textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1203 AM PDT Fri Apr 10 2026

- Rain and thunderstorms through the weekend

- Gradual warming and drying trend next week

SHORT TERM

Issued at 1203 AM PDT Fri Apr 10 2026 (Today and tonight)

A surface low near 37 N, -128 W in the Eastern Pacific Ocean will continue to trek eastward through the night. Rain showers from the main rain band will push into the area around 2-3 AM and push off to the northeast by the afternoon. Isolated rain showers/thunderstorms will remain possible behind it. Rainfall totals will be dependent upon where rain showers/thunderstorms develop and thunderstorm development will be dependent upon where breaks in the clouds allow for the convective temperature to be realized. Rainfall is expected to be strictly beneficial. The only caveat would be for minor flooding in poor drainage and urban areas if a heavier rain shower/thunderstorm develops and/or rain showers/thunderstorms train. Thunderstorms will pose the risks of lightning, locally heavy rainfall, erratic/gusty winds, and small hail. Weak low- level shear does not support a mention of rotation leading to tornadoes and/or waterspouts.

LONG TERM

Issued at 1203 AM PDT Fri Apr 10 2026 (Saturday through Thursday)

An upper-level low in the Gulf of Alaska will dig down the West Coast and absorb the first low as it does so on Saturday. This will be a whole new ballgame as this system is much more dynamic by nature with the inclusion of the jet stream. The cold front will sweep through Saturday afternoon and evening bringing widespread rainfall to the region. Even with the QPF continuing to trend higher with 1"-2" and up to 4" in the coastal ranges when all is said and done, this rainfall is expected to be purely beneficial thanks (I guess) to the dry March that we are coming off of. The three ingredients for thunderstorms of lift, instability, and moisture will all be in place Saturday. The merging of the two lows and the associated cold front will offer lift, the atmosphere will destabilize as cold air filters in aloft, and remnant tropical moisture will remain in place through the cold frontal passage. Thunderstorms will pose the risks of lightning, locally heavy rainfall, erratic/gusty winds, and small hail. With the reintroduction of the jet stream and veering winds in the low- levels, rotation yielding waterspouts and/or weak tornadoes is possible. The slower trend of returning to ridging is thanks to the low filling instead of remaining progressive Sunday. As a result, wraparound rain showers and thunderstorms are now in the forecast all of Sunday. Cold air with remnant moisture will allow for snow across the highest peaks on Sunday. Anglers should take special note of the expected weather and have a plan to reach safe harbor quickly when the weather turns. Even without thunderstorms, the marine conditions will deteriorate through the day Saturday. If thunderstorms develop, the associated wind gusts are capable of capsizing small vessels. Fishing leads to more lightning deaths in the U.S. than any other activity. When thunder roars, head indoors!

Heights will slowly begin to rise on Monday, kicking off a warming and drying trend. Widespread below normal temperatures are expected Monday before slowly rebounding to seasonal normals by Thursday. As we get back into the growing season, patchy frost is possible in sheltered locations Monday morning due to the combination of cold conditions and remnant moisture. The frost risk decreases through the week as temperatures slowly rise and drier air filters in.

AVIATION

(06Z TAFS) Issued at 1003 PM PDT Thu Apr 9 2026

MVFR-IFR stratus is developing at the coast and moving inland through the next few hours, and will be reinforced overnight by the first band of showers expected to arrive sometime Friday morning. As the showers pass, ceilings should lift to become generally VFR-MVFR, along with isolated to scattered thunderstorms across the region, with the best chances focused on the North Bay and East Bay on Friday afternoon and evening. Have decided to go ahead and put VCTS in for the STS, APC, and LVK TAFs for the 18-00Z time period, but note that this is a lower confidence forecast. Chances for thunderstorms decrease on Friday evening, but scattered showers remain possible through the end of the TAF period, with another band of widespread rainfall expected after the end of the TAF period on Saturday afternoon through Sunday. Onshore wind flow will continue to diminish tonight, with light winds overnight before moderate southwest winds prevail through much of Friday. Gustier winds are expected where thunderstorms do develop.

Vicinity of SFO... VFR conditions continue through the next couple of hours. MVFR conditions will set up overnight as a band of showers passes through the terminal area through Friday morning, with VFR conditions with mid-level clouds returning once the showers pass. Friday afternoon should see a moderate southwesterly flow develop through the evening. There is around a 25-35% chance of thunderstorms at the terminal Friday afternoon and evening, but confidence is too low to put VCTS or PROB30 in the TAF at this time. Chances for showers continue through the end of the TAF period.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR stratus is developing around the terminals with a "sucker hole" at present around MRY, with a band of showers expected to pass through the region through the course of Friday morning. VFR conditions return as the showers pass with breezy southwest winds developing Friday afternoon. There is a 20- 35% probability of thunderstorm development at the terminals Friday afternoon and evening, but confidence is too low to put VCTS or PROB30 in the TAF at this time. Chances for showers continue through the end of the TAF period, with a low confidence forecast that winds at the terminals will abate overnight with potential development of MVFR stratus.

MARINE

(Tonight through next Wednesday) Issued at 1003 PM PDT Thu Apr 9 2026

Unsettled weather is expected Friday through the weekend, including increasing winds, building seas, and a few rounds of thunderstorms. Thunderstorms will be capable of producing frequent lightning, gusty and erratic winds, localized heavy rain, small hail, and waterspouts. Gentle to moderate south to southwest winds will become fresh to strong by Saturday, with occasional near gale force gusts. Winds become westerly late Saturday and northerly by late Sunday as the low pressure system passes near the northern waters. Fresh north winds last through midweek.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Gale Watch from Saturday morning through late Saturday night for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.