textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 333 AM PDT Fri Mar 20 2026

- The last day of the long-duration, record- breaking temperatures, and Moderate HeatRisk.

- Elevated potential for grass fires today, but fire concerns begin to east into the weekend.

- Gradual cooling trend begins this weekend and lasts through the next work week.

UPDATE

Issued at 844 AM PDT Fri Mar 20 2026

A clear morning across the region, with the clear skies continuing throughout the day. This morning's 12Z (5 AM PDT) sounding at OAK set another 850 mb temperature record at 23.4 C, a maximum temperature record that is not reached again until the middle of May. It follows that today is another day of extreme heat across the region with a lot of daily temperature records, and possibly some monthly records, under threat. For more details on the expected conditions today, and the cooling trend this weekend, see the previous discussion.

DialH

SHORT TERM

Issued at 333 AM PDT Fri Mar 20 2026 (Today and tonight)

Another warm morning followed by a hot day. Overnight lows plateaued in the mid 50s to mid 60s for the lower elevations, while some of the higher elevations remain in the 70s and a few along the Big Sur Coast remain in the 80s. The warm start will allow another day of widespread 80 to 90 degree high temperatures for all but the immediate coast. A very compressed marine layer will affect those coastal areas, but its influence will not make it very far inland. Today will offer some of the warmest temperatures of the week as air aloft (850 mb temperatures) continue to cook. Some areas may be slightly cooler than previous days by a degree or two as the ridge of high pressure weakens slightly into the afternoon.

The weakening of the high pressure and the influence of a trough to our north will allow for improved cooling into the night and pull us out of heat advisory criteria into the weekend. As such, it doesn't look like the current Heat Advisory will need to be extended into the weekend. But we'll still be far from average high temperatures.

LONG TERM

Issued at 333 AM PDT Fri Mar 20 2026 (Saturday through Thursday)

Saturday will be the first day of notable relief from the week-long heat event. Most of the region will see the upper 70s to mid 80s for highs; which is an improvement from previous days, but is still 10 to 15 degrees above average. The immediate coast looks to fall back into the lower 60s, which is around average and will benefit from a slight expansion of the marine layer that will move slightly more inland in the next few days.

Temperatures overall will continue to slowly cool going into the next work week as the jet stream sees a modest zonal flow develop with some very slight ridging to the south. This will allow for weak onshore flow and an expanding marine layer. Models are hinting at a weak southerly surge of marine stratus and fog moving up the Big Sur coast early Sunday, which could result in much cooler coastal temperatures in Monterey County, especially if it makes it all the way to Monterey Bay. Longer term models also entertain the possibility of coastal drizzle along the tail end of a cold front in the mid week, but these chances look unimpactful.

The extended model outlooks continue to offer a building trough at the end of the month, which could push a deteriorating low pressure down the coast from the Pacific Northwest. This could result in good chances for light, scattered rain, but this is way to far out to speak on this with too much confidence. It's still worth keeping an eye on as the forecast continues to develop.

AVIATION

(18Z TAFS) Issued at 1041 AM PDT Fri Mar 20 2026

Dry boundary layer will continue VFR conditions through the first half of tonight for all terminals. After 06Z the sfc pattern begins to change with some hi-res models showing a quasi- southerly surge (more in cloud field and less on wind field) coupled with a stratus deck developing over the Pacific with an approaching cold front to the NW. That being said, highest confidence for cigs will be for HAF,MRY, and SNS.

Vicinity of SFO...VFR. E push through this afternoon then switching W with breezy winds after 20Z. Some low level moisture does sneak into SF Bay. Previous TAFs for SFO/OAK had few/sct for Saturday AM. This is a good approach for now.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...VFR through at least 06Z. After 06Z moisture begins to increase along the Big Sur coast and from the NW. Will keep the arrival of IFR cigs and some patchy fog at LIFR. Conf is 40-50% on low end LIFR.

MARINE

(Today through Wednesday) Issued at 844 AM PDT Fri Mar 20 2026

Lingering high pressure will maintain northerly flow over the coastal waters today. Northwesterly winds will increase this weekend as a cold front sweeps through. Gales will develop across the northern waters Saturday into early Sunday. Hazardous seas will develop due to strengthening winds.

CLIMATE

Issued at 1021 PM PDT Thu Mar 19 2026

The following are the record high temperatures at the long term sites for March 20th.

Location Mar 20

Santa Rosa 84 in 2004 San Rafael 82 in 1960 Kentfield 82 in 2001 Napa 86 in 2004 Richmond 81 in 2004 Livermore 87 in 1915 San Francisco 78 in 2004 SFO Airport 78 in 2004 Redwood City 82 in 2004 Half Moon Bay 75 in 2010 Oakland Museum 78 in 2001 San Jose 78 in 2004 Salinas Airport 80 in 1934

The following are the record high temperatures at the long term sites for the entire month of March.

Location

Santa Rosa 92 March 19, 2026 San Rafael 89 March 19, 2026 Kentfield 91 March 28, 1923 Napa 92 March 17, 1914 Richmond 88 March 18, 2026 Livermore 90 March 25 and 26, 2025 San Francisco 87 March 11, 2005 SFO Airport 85 March 25, 1952, March 17, 2026, March 19, 2026 Redwood City 93 March 17, 2026 Half Moon Bay 83 March 31, 2000 and March 17, 2004 Oakland Museum 89 March 17, 2026 San Jose 89 March 14, 2015 Salinas Airport 93 March 18, 2026

MTR WATCHES/WARNINGS/ADVISORIES

CA...Heat Advisory until 8 PM PDT this evening for CAZ006-502>506- 508>510-512>518-528>530.

PZ...Small Craft Advisory from 3 PM this afternoon to 3 PM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm.

Gale Warning from 3 PM to 9 PM PDT Saturday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory from 3 AM to 9 PM PDT Saturday for Pt Reyes to Pigeon Pt 0-10 nm.

Small Craft Advisory from 3 PM to 9 PM PDT Saturday for Pigeon Pt to Pt Pinos 0-10 nm.

Small Craft Advisory from 9 AM to 9 PM PDT Saturday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory until 3 PM PDT Saturday for Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory from 3 PM this afternoon to 9 PM PDT Saturday for Pigeon Pt to Pt Pinos 10-60 NM.