, Issued at 1221 AM PDT Tue Jul 28 2026 (Today and tonight)
If you read the evening AFD update micro-climates were highlighted. Seems fitting to kick off this AFD with another micro-climate highlight. If one looks at the overnight satellite imagery they'll notice only patchy stratus developing. I do expect more by morning, but patchy for now. So why is it patchy, pockets of offshore flow most notably over the N Bay and along the Big Sur coast. Offshore flow is a drying and warming wind for our region. Taking a closer look at Big Sur there are two sensors called Highlands Peak. It's close to midnight and both are reporting temperatures near 80 degrees. N to NE flow leads to compressional warming as the air descends the Santa Lucias, hence the warm temperatures.
Tuesday will be another pleasant day weather wise most areas. The longwave pattern continues to advertise broad upper level troughing just offshore and upper level ridging to the SE. Similar to Monday we'll see a large spread of temps from the coast to the interior. Onshore flow will keep coast/bays in check with highs in the 60s/70s. Farther inland with marine layer influence will see much warmer temperatures with highs in the upper 80s to near 100.
Given the temperature contrast expect another round of breezy afternoon winds in the valleys and inland gaps/passes.
Tuesday night the upper level trough begins to ease with upper level ridging building in from the east. As such, a more stable marine layer will develop with slightly better stratus coverage. Above the marine layer temperatures will be on the milder side.
..issued at 1221 AM PDT Tue Jul 28 2026 (Wednesday through Monday)
Wednesday will be a transition day as the longwave pattern shifts from nearby trough to a building ridge. It should be noted the building ridge from the east brought very dangerous heat to the Desert SW. Not expecting that here, but a marked warm up nonetheless. Expect an initial jump in temps of 3-5 degrees from Tuesday to Wednesday. Still seeing some night/morning marine stratus given lingering onshore flow. Additionally, we will continue to see the large temp spread from the coast to the interior.
Thursday through Monday - The heat dial gets turned up each day and peaks over the weekend before moderating early next week. The very warm upper level ridge to the east will overspread the region for much of the long term. Projected 850mb temps will be in the mid to upper 20s, which when fully mixed will easily support temps in the 105-110 range. However, onshore flow remains at the surface. Therefore, the fullest potential of the airmass will only be realized across the interior. That's the key to keeping the coastal areas and bays in check temp-wise - onshore flow. Some guidance does show periods of easing onshore flow and that has bust potential written all over it with coastal areas ending up warmer than forecast. Confidence isn't high enough to fully buy that solution just yet. Much higher confidence exists for interior locations to experience triple digit heat. Given the very mild airmass thermal belts will be very active too with minor relief in the hills overnight. Could easily see temps staying in the upper 60s to mid 70s in the hills. Therefore, as daytime temperatures increase and less nighttime relief is observed overall HeatRisk increases. While most areas without any marine influence will be moderate HeatRisk from Thursday through early next week there will be pockets of Major to Extreme for interior Monterey/San Benito. As the weekend forecast becomes more clear will need to take a look to see if a heat advisory is needed.
Longer range guidance diverges on extent of the heat, but some guidance keep the heat going for much of next week.
(12z TAFS) Issued at 439 AM PDT Tue Jul 28 2026
Areas of coastal stratus /MVFR-IFR/ continue to develop and move inland on onshore winds otherwise it's clear /VFR/. Diurnal mixing will reduce stratus coverage back to the coastline today then areas of coastal stratus /MVFR-IFR/ redevelops and moves inland tonight and Wednesday morning.
Vicinity of SFO, Stratus /IFR/ mixes out to VFR by 17z today then redevelops 06z tonight and prevails until 17z-18z Wednesday. Onshore winds 15 to 25 knots today, decreasing to near 10 knots tonight and Wednesday morning.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Stratus /IFR/ mixes out to VFR by 18z today then redevelops mid evening and prevails through 12z Wednesday morning. Onshore winds 5 to 15 knots.
(today through Sunday) Issued at 434 AM PDT Tue Jul 28 2026
Fresh to strong northwest breezes will persist through the week into next weekend, especially across the outer waters. Frequent gale force gusts are likely across coastal jet regions along Big Sur and Point Reyes. Moderate seas will become rough by the middle of the week with the increasing northwest winds. Long period southerly swells will continue along our coastal waters into the weekend.
Issued at 145 PM PDT Sun Jul 26 2026
Distant tropical cyclones in the Eastern Pacific will continue to generate 16-18 second (long-period) southwesterly swell which has reached the coastline of the San Francisco Bay Area and Central Coast. As such, sneaker waves and strong rip currents are the primary concerns. Breaking waves can reach up to 12 feet along some south and southwest facing beaches and break points, such as Santa Cruz, Pacifica, and parts of Stinson or Ocean Beach. This can be particularly surprising when wave heights increase suddenly after a period of seemingly tranquil wave action. In fact, sneaker waves can have 20+ minutes in between the larger sets (breaking waves) with significant "flat/calm looking" times between them. Due to the long period, sneaker waves are powerful and can catch beachgoers by surprise, resulting in people and pets being swept into the cold, turbulent ocean. Rip currents are strong enough to pull even the strongest swimmers away from shore. Check marine conditions before you head out! Swim near a lifeguard, if possible. Maintain a safe distance from the water, and stay away from jetties, piers, beachside rocks, and other waterside infrastructure. Never turn your back to the ocean and if you have small children or pets at the beach, please keep an eye on them. Hazardous beach conditions are anticipated to persist through Saturday afternoon.
Ca, Beach Hazards Statement through Saturday afternoon for CAZ006- 505-509-529-530.
PZ, Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Mry Bay-SF Bay N of Bay Bridge.
Small Craft Advisory until 3 PM PDT Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm.
Gale Warning until 3 PM PDT Wednesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
