Marine Weather and Tide Forecast for Marina, CA

UPDATE
Issued at 950 AM PDT Wed Aug 5 2026

Solid marine layer this morning impacting the Bay Area and Central Coast. As another forecaster in the office pointed out this morning pretty impressive to see an over performing marine layer deepen to nearly 1800 feet with anomalously high 500mb heights. Not as much drizzle being reported this morning, but the ample moisture in the low levels has led to mist. Above the marine layer is a completely different story. High elevation sensors showed another classic nocturnal drying event this morning.
Sensors showed humidity "recovery" to around 30 percent yesterday evening then humidity values plummeted through sunrise as the marine layer moved inland. This would definitely be a fire weather concern, but fortunately winds are relatively light. Other item of note this morning is some high level smoke being picked up by satellite lurking over the coastal waters and potentially the North Bay. Surface sensors are not showing it reaching the ground as of now therefore it's likely high level drift smoke.

For today - the over performing marine layer is bringing much needed relief to the interior. No Heat Advisories are needed as temperatures cool and HeatRisk concerns decreases. The marine layer will slowly ease back to the coast, but linger for the day.

No update needed this morning.

Will be focusing on another round of heat later in the week and developing near critical fire weather conditions.

MM

SHORT TERM
Issued at 1148 PM PDT Tue Aug 4 2026 (Tonight through Thursday)

The picture from space this evening shows stratus snaking through the the region. Earlier model guidance struggled with the onset of its arrival and to some extent the depth as well. It's currently around 1000ft and has the potential to get to 1200ft, with coastal drizzle and patchy fog possible tonight and into Wednesday morning.
The good news is that this will cool temperatures overnight and perhaps take a bit longer to retreat to the coast Wednesday morning.
With ridging not as strong and those factors in place, the threat for Moderate HeatRisk has been pulled back with only a few pockets found across the interior Central Coast and interior E and S Bay regions. Some of those pockets include areas above the marine layer, where temperature recovery won't be as great. Like the prior shift, will not be issuing a Heat Advisory for Wednesday.

Wednesday night into Thursday morning, the forecast will be on repeat. Look for the marine layer and associated stratus to seep into the region leading to another cloudy night.

LONG TERM
Issued at 1148 PM PDT Tue Aug 4 2026 (Thursday night through next Tuesday)

The ridge starts to build back into the region on Thursday, which will compress the marine layer to perhaps 500ft for the next few days. At the surface, winds will have shifted from the south to a more north/northwesterly flow; however, aloft, guidance shows the southerly flow holding. Deterministic models and ensembles show a slug on moisture pushing into our region Thurday-Saturday giving us PWATs ranging from 0.75-1.0, which could lead to things feeling humid. In terms of the heat portion of the forecast, it looks to be on track. Data continues to signal 850mb temps in the 28-30C range, leading to toastier daytime and overnight temperatures. Highs, especially for interior areas and those not affected by the marine layer, will be in the 90s to low 100s while low temperatures there fall into the upper 60s-70s. Widespread Moderate HeatRisk is expected, with some pockets of Major HeatRisk on Saturday.

Sunday and Monday, the upper level pattern shows the ridge flattening some. The latest NBM seems to keep temperatures a tad warmer on Sunday, with the more notable interior cooling trend occuring on Monday and Tuesday.

AVIATION
(12Z TAFS)
Issued at 509 AM PDT Wed Aug 5 2026

Strong 500 mb high pressure remains over the area, however there is also a stationary and weak surface low pressure system over the CA coastal waters within the marine layer. Counter-clockwise winds with the surface low is entraining higher surface dewpoint air (water vapor) from the west, the water vapor upon closing in on the CA coastline is crossing a cooler gradient in sea surface temperatures.
This is resulting in stratus and mist/fog /MVFR-IFR/ reaching the coastline and inland on onshore winds. Even under strong high pressure, the marine layer has deepened to ~ 1800 feet. It's sharply drier and warmer aloft at and above the marine layer temperature inversion, supporting nocturnal radiative cooling to space. Onshore winds are supported by a 2.4 mb SFO-SAC pressure gradient. It'll take the morning for stratus, mist/fog to mix out to VFR.

Wildfire smoke from the Pacific Northwest may also get entrained into the aforementioned low over the coastal waters today based on recent high resolution near surface smoke forecasts. If smoke is drawn into the stratus, this may lower surface visibilities in a mix of smoke, haze and mist today.

Coastal stratus, mist/fog /MVFR-IFR/ return inland on onshore winds tonight and Thursday morning.

Vicinity of SFO...Stratus /MVFR/ until 20z today then mixing out to VFR. Stratus returns late tonight-early Thursday by 10z. Light and variable wind becoming northwest 10 to 15 knots in the afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Stratus /IFR/ until late morning then mixing out to MVFR-VFR. Stratus /IFR/ returns this evening and overnight. Mainly northwest winds 5 to 15 knots.

MARINE
(Today through Monday)
Issued at 950 AM PDT Wed Aug 5 2026

Light to gentle south to southwesterly breezes will persist through Thursday along with seas between 2-6 feet. Winds will begin to increase again out of the northwest going into Friday with building seas and hazardous conditions for small craft returning for the upcoming weekend.

FIRE WEATHER
Issued at 1000 AM PDT Wed Aug 5 2026

Marine layer brought relief to lower elevations this morning, but above the marine layer another nocturnal drying event bringing single digit RH. Simply put, little to no recovery last night.

Cooler and slightly more humid conditions are expected across the interior today and Thursday. Despite the "cooldown" temperatures across the interior will still be in the 90s to low 100s Wed/Thu with min RH teens. Still expecting an onshore push each afternoon/evening with breezy to gusty winds leading to a few hours of elevated fire weather conditions.

High pressure will build back over the district late Thursday into Friday. As such, the marine layer will become more compressed and interior heat increasing and humidity decreasing. Peak times of greatest concern will be each afternoon/evening Sat/Sun. This will push Energy Release Component (ERC) back up to critical levels.
ERC values have climbed above the 97th percentile within the Interior Central Coast and Diablo-Santa Cruz (Diablo Mountains and Santa Cruz Mountains) zones with the Mid Coast to Mendocino Zone (North Bay) to reach the 97th percentile this week. Large fires become more frequent after ERC values cross the 90th percentile with extreme burning conditions expected with ERC values above the 97th percentile. 100 hr fuels continue to respond to the hot and dry conditions with values reaching critical levels across the region. Latest intel also shows Live Fuel samplings are also heading toward critical levels.

Lastly, we're tracking some high level moisture streaming in from the south Friday and over the weekend. As of right now, upper level instability seems limited so high based thunderstorms are not likely. If anything, some high cirrus is possible with some higher dew points.

MM

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...None.