textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 107 PM PDT Fri Apr 3 2026

- Moderate to strong offshore flow through remainder of today

- Warmer temperatures return Saturday and Sunday before a cooling trend begins next week

- Beneficial rain chances increase mid to late next week

SHORT TERM

Issued at 107 PM PDT Fri Apr 3 2026 (This evening through Saturday)

Breezy offshore winds continue through early tomorrow morning. The strongest wind gusts have largely been confined to the higher elevations of the North Bay Interior Mountains and the Diablo Range. The strongest gust reported so far was 67 mph at the Mt. St. Helena West Station (elevation of 4340 ft) at 7:30 AM this morning. At that time the SFO-WMC pressure gradient peaked at -10 mb. Winds have since come down slightly but are likely to increase again during the afternoon and evening hours. The SFO-WMC gradient has regained strengthen over the last few hours (after initially weakening from early this morning) with the 11AM observation coming in at -9.80 mb. GFS guidance most closely resembles the observed SFO-WMC gradient and keeps offshore winds continuing into Sunday. Another, brief, round of breezy winds is possible across the higher elevations early Saturday morning before winds decrease through the remainder of the day.

High temperatures today are seasonably warm in the 60s along the coast and 70s across the interior. This is running about 5 to 10 degrees above normal for this time of year and is the result of upper level ridging and surface high pressure building in. The warming trend continues into Saturday with high temperatures in the 70s to 80s expected (15-20 degrees above normal). Currently only Minor HeatRisk is forecast today and tomorrow thanks to good overnight cooling. Light, offshore winds prevail on Saturday which will play a role in keeping coastal areas warmer thanks to an effect called downsloping. Downsloping occurs when wind is forced down the leeward side of the mountain with an air parcel compressing (and warming) as it sinks. This type of setup is favorable for bringing much warmer and drier temperatures directly along the coast compared to the normally cooler temperatures we observe. For the afternoon forecast package, did adjust high temperatures up slightly for Saturday and Sunday given that the deterministic NBM was running much cooler than other models. Given the very dry atmosphere, fog is not expected to develop tonight with HREF only showing high clouds moving through.

LONG TERM

Issued at 107 PM PDT Fri Apr 3 2026 (Saturday night through next Thursday)

Above normal temperatures continue into Sunday with highs remaining 15-20 degrees above normal. This keeps temperatures in the 80s across the interior and 70s along the coastline. There is a little more uncertainty with regards to Sunday's high temperatures than Saturday's. On Saturday, the center of the upper level ridge is centered more over California while on Sunday the ridge is progressing rapidly eastward. As the ridge departs, the SFO-WMC pressure gradient is expected to reverse (becoming positive) and onshore flow returns. Currently, offshore winds are likely to remain through at least Sunday morning but potentially into early Sunday afternoon. The longer offshore winds stick around, the more surface temperatures are able to warm. The current thinking is that temperatures will peak early to mid afternoon and start decreasing as the sea breeze/onshore winds kick in. Another factor is the potential for the marine layer to redevelop, bringing a return of coastal stratus and fog. The marine layer now looks to return overnight Sunday into Monday than Sunday afternoon/evening. This limits the impact it would have on Sunday's high temperatures but it's worthwhile noting that the signal is there for the marine layer to redevelop heading into next week. There is the potential for some daily high temperature records to be broken Saturday and Sunday (one site being Half Moon Bay) depending on how high temperatures warm.

Temperatures cool slightly, becoming seasonably warm, into the 70s to low 80s across the interior Monday and Tuesday as upper level ridging progresses eastward and zonal flow returns. The coast will be noticeably cooler with seasonal high temperatures in the 60s expected. The cooling trend continues through late next week as an upper level trough moves through the West Coast. This system will bring us our next chance of beneficial rain. Totals are still light with the majority of the region seeing less than a quarter of an inch. The higher elevations of the Santa Cruz Mountains and the Santa Lucia Range may see between 0.25 to 0.5" of rain. There is also the potential for this system to bring locally gustier onshore winds to the coast and across the higher elevations on Wednesday.

AVIATION

(00Z TAFS) Issued at 424 PM PDT Fri Apr 3 2026

High confidence of VFR through the TAF period, with moderate confidence of a few high clouds tonight into Saturday. Gusty offshore winds prevail across the interior regions, with a northwesterly breeze developing at the coast. Winds will decrease at the terminals overnight with light winds through Saturday morning. Although LLWS magnitudes are not high enough to note in the TAFs, the continuing winds aloft may make takeoffs and landings bumpy from the interior terminals. Saturday afternoon winds look to be largely a repeat of today's pattern with offshore winds in the interior, balanced by an onshore breeze in the coastal regions.

Vicinity of SFO... High confidence of VFR through the TAF period with possible high clouds overnight through Saturday. Breezy northwest winds should arrive within the next hour or two, persisting through the late evening hours when winds become light and southeasterly. A similar pattern with breezy northwest winds in the late afternoon and evening hours and light winds otherwise should persist through Saturday.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... High confidence of VFR through the TAF period with possible high clouds overnight through Saturday. Gentle to moderate northwest winds continue through the evening hours with light drainage winds overnight. At SNS, the southeast winds will pick up early Saturday morning before turning northwest late in the afternoon, while at MRY, onshore flow develops in the afternoon hours on Saturday.

MARINE

(Tonight through next Wednesday) Issued at 424 PM PDT Fri Apr 3 2026

Fresh to strong northerly breezes will persist over the northern outer waters through late tonight. Otherwise winds and seas will abate tonight and through the weekend. Light to moderate northerly breezes prevail this weekend and into next week. A low pressure system over the Pacific will approach the coastal waters and bays by the middle of next week bringing a chance of rain.

CLIMATE

Issued at 110 PM PDT Fri Apr 3 2026

The following are the record high temperatures at the long term stations for April 4th and April 5th.

Location April 4th April 5th

Santa Rosa 88 in 1961 90 in 1939 Kentfield 85 in 1957 88 in 1924 San Rafael 86 in 1960 87 in 1957 Napa 86 in 1985, 1960 86 in 1989, 1957 Richmond 89 in 2011 83 in 1989 Livermore 87 in 1959 84 in 1989, 1916 San Francisco 84 in 1985 88 in 1989 SFO Airport 82 in 1985 84 in 1989 Redwood City 86 in 1960 87 in 1989 Half Moon Bay 77 in 2011 74 in 2016 Oakland Museum 85 in 1985 85 in 1989 San Jose 87 in 1960 89 in 1989 Salinas Airport 86 in 1989, 1960, 1952 95 in 1989

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 3 AM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM.