Issued at 952 PM PDT Sat Mar 14 2026
Surface high pressure is advancing over northern and central California and into the Great Basin. 500 mb heights are also steadily increasing with greater thermal ridging developing in the lower to mid levels tonight through Sunday. Surface pressure gradients are increasing, ACV-SFO is 6.3 mb and UKI-STS is strong at 2.5 mb. The WMC-SFO pressure gradient will strengthen tonight and Sunday morning nearing ~ 10 mb Sunday morning. We're already today seeing signs of downsloping and warming in the North Bay due to north to northwest winds. Santa Rosa NWS coop site high temp peaked well above mid March normal at 79F (not far from today's record high 82 in 2004). Sonoma County Airport high temperature was well above normal at 80F.
There is a strong temperature gradient over the northern CONUS, jet stream with positive west-east i.e. zonal anomalies for early March and a 500 mb wave pattern including overall strengthening of a long wave ridge. As advertised strong long wave ridging (with 500 mb heights 590+ decameters) will shift to and become focused over southwestern U.S. through much of if not all this week. This is a strong dynamic development that'll place our forecast area under well above normal warm/hot weather with record high temperatures. For additional info on the forecast please see the discussions below.
Equipment report: 00z 03/15/2026 Oakland upper air sounding is unavailable due to a ground equipment failure. Techs are aware of the issue. It's uncertain at this time if there'll be a 12z upper air balloon launch.
, Issued at 1205 PM PDT Sat Mar 14 2026 (This evening through Sunday)
The combination of a shallow marine layer and weak, shortwave trough is keeping temperatures slightly cooler today. High temperatures across the interior will be in the 70s with the warmest locations (generally higher terrain) reaching the low 80s. Coastal temperatures are forecast to peak in the low to mid 60s. Low level clouds are currently clearing at a faster rate today than they were at this time yesterday. This is increasing confidence that temperatures for the coast will not need to be adjusted downwards to account for prolonged cloud cover like they were yesterday. A shallow (500 ft) marine layer is likely to redevelop again tonight along the coast before upper level ridging suppresses it next week. This will bring a low potential for fog along the coast tonight into early Sunday morning. High clouds are expected to move in across the region this afternoon and continue into the overnight hours. Fog/low clouds are not expected to be widespread across the Bay Area overnight but there may be some patchy instances of stratus/fog directly along the SF Bay Shoreline. Overnight lows generally stay in the upper 40s to low 50s across.
..issued at 1205 PM PDT Sat Mar 14 2026 (Sunday night through next Friday)
Sunday marks the start of our heatwave with highs rising into the mid to upper 80s across the interior and 60s to low 70s along the coast. High clouds return overnight Saturday into Sunday which will keep afternoon temperatures a few degrees cooler than forecast next week. On the synoptic scale, upper level ridging reaches the West Coast late Saturday/early Sunday and will build throughout the day on Sunday. This initially results in a 591 dam upper level high centered just offshore of California. The center of this high will slowly shift eastward Monday through Wednesday before strengthening to 594 dam (500 mb heights) and remaining almost stationary over the Southern California/Arizona border through late next week.
The overall forecast for the upcoming heatwave with temperatures running 20-30 degrees above normal remains on track but there are a few changes to address. Initially, the warmest days were expected to be Monday through Wednesday but it now appears more likely that the warmest days will be Wednesday to Friday. This is largely a result of the ridge restrengthening mid to late next week and remaining nearly stationary (compared to earlier in the week) over the desert southwest. The temperature difference between each day is relatively small and each day will be within 1-3 degrees of each other. High temperatures will be in the upper 80s to mid 90s across the interior and upper 70s to mid 80s along the coastline. The hottest locations will be across interior Monterey and San Benito Counties, the Santa Cruz Mountains, the North Bay Interior Mountains, East Bay Hills, and potentially the southern Santa Clara Valley. Both daily records and potentially all time March records are still on the table Monday through Friday next week. Long range guidance suggests we could see these warmer temperatures extend into next weekend before we see some relief (still above normal but only by 10-15 degrees) the week after. There is the potential to break some upper air records at OAK this week (namely 850 mb temperatures and potentially 500 mb heights). Probabilistic guidance is showing the potential for portions of the higher elevations to reach the low 100s late next week. The most likely areas to break 100 would be the Gabilan Range but the NBM is showing a low (~10%) chance of portions of the Santa Cruz Mountains, the southern Santa Clara Valley (Gilroy/Hollister), and the East Bay Hills reaching 100 as well.
This is our first major heatwave of the year and it is going to be a marathon. We are primarily expecting Moderate HeatRisk with some relief overnight from overnight lows in the upper 50s to low 60s. There are patches of Major HeatRisk (impacts most people) in the higher elevations of the Santa Cruz Mountains and interior Central Coast next week. Given the long duration of this heat event, susceptibility to heat related illnesses will increase throughout the week. If you are going to be outside for prolonged periods of time make sure you are drinking plenty of water and allowing time to rest in the shade. Never leave people or pets unattended in the car. If possible, avoid going outside during the peak afternoon heat (approx. 10AM - 4/5PM). Heat Advisories will be in effect for much of the Bay Area and Central Coast Monday through Friday with some potential to expand into next weekend.
Expect increased potential for grass fires next week as much above normal temperatures cure small, fine fuels (grass). Offshore winds will remain light to moderate which will help mitigate how much any fires that do develop can grow. If you are participating in any outdoor activities (camping, offroading, hiking, etc) exercise caution when using fire and be aware that the risk of grass fires will be elevated next week.
(06z TAFS) Issued at 1000 PM PDT Sat Mar 14 2026
Low CIGs are forming along the coast as winds reduce affecting HAF then MRY slightly later into the night. Spotty CIGs will push into the bays further into the night, bringing CIGs to OAK and SNS then SJC into Sunday morning. Cloud cover erodes into the afternoon but hazy conditions look to form in some of the valleys and along the coast. Winds build in the late morning and afternoon, but look to become light into that night.
Vicinity of SFO, VFR through the TAF period. Moderate to breezy northwest winds linger into the night before reducing. Winds become light and variable into Sunday morning with some slight reductions in visibilities. Northwest winds build again Sunday afternoon and last into late that night before becoming light again.
SFO Bridge Approach, IFR-level clouds look form around the eastern SF Bay in the early to mid morning, with the potential for some moving through the approach until the late morning before the clouds clear.
Monterey Bay Terminals, VFR lasts into the night before winds become light and LIFR CIGs arrive to MRY. IFR CIGs will be slower to arrive to SNS, but are in the late night and into early Sunday morning. These lower CIGs will also be accompanied by reduced visibilities. VFR returns in the late morning as moderate west to northwest winds build. Slight haze will be possible through much of Sunday. Winds become light again Sunday night.
(tonight through next Friday) Issued at 843 PM PDT Sat Mar 14 2026
Fresh to moderate north/northwest continue to produce steep fresh swell. Wind and seas will ease over the inner water Sunday afternoon followed by the outer waters on Monday. Wind and seas are expected to remain relatively calm through the remainder of the week into next weekend.
Ca, Heat Advisory from 10 AM Monday to 8 PM PDT Friday for CAZ006- 502>506-508>510-512>518-528>530.
PZ, Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 AM PDT Monday for Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 9 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM.
