Marine Weather and Tide Forecast for Hercules, CA

SHORT TERM
Issued at 150 PM PST Fri Mar 6 2026 (This evening through Saturday)

All focus remains on the warm up over the weekend. High pressure is dominating the Eastern Pacific while an upper trough and cutoff low linger across the desert Southwest and Southern California. This pattern is having a two fold affect on the Bay Area and Central Coast forecast. First is the broad area of high pressure over the East Pacific. While typically a summertime pattern, it is having summerlike influences on our early spring time. Under this pattern we expect clear skies and warming conditions. This pattern also sets up winds out of the North along the coast. When this happens the area can experience coastal upwelling of cooler subsurface water. In turn this can lead to sea/land breeze circulation as well as some low clouds and fog to form in the lowest layers in the late day and overnight hours. The surface high pressure is being analyzed by the ocean prediction center at 1037 mb, which is a decently stout high for March. The second item is that of the upper trough/cutoff low. This is more of a wind steering items than anything else. When this pattern sets up, adjacent to the high pressure over the East Pacific, it takes the winds that would normally come from the North and veers them toward the Northeast.
This means we can get a bit more offshore flow across the region.
Offshore winds can bring adiabatic warming (downsloping) for many portions of the area.

This pattern over the weekend will bring the warmth that is associated with a strong area of high pressure combine with offshore winds will cause temperatures for Saturday and Sunday to run anywhere from about 10-20 degrees above normal. Models typically handle this pattern decently well, but can run a few degrees too cool at times. Looking at the ensemble envelope we leaned more towards the 75th percentile of the NBM, but did this with the NBM EXP. The place that models do not handle well in this pattern is San Francisco. This is for a few reasons, but the biggest is being a small piece of land surrounded by water on three sides. We look at wind direction carefully to give us an idea of what will happen in SF during these pattern and Saturday morning (some degree Sunday morning) will see winds at 925 mb from the Northeast at about 30 knots. So far models have been a little weak on the 925 winds. Even so, with 30 knots and a coupled atmosphere, high temperatures for SF on Saturday have a good probability (greater than 70%) of exceeding 80 degrees in a few locations. No models will pick this up and forecast was manually adjusted to account for this. The piece to watch will the minimum temperatures for early Saturday and Sunday morning. If we start near 60 degrees in SF, it is almost a sure bet that SF will pop into the low to mid 80s. If we do it again on Sunday morning, the pattern is similar enough that we could pop again for a short time on Sunday.

Everyone else around the Bay Area, rest assured, you were not forgotten. Numerical models handle your locations better than they handle SF. In short, it's going to be a warm weekend.

LONG TERM
Issued at 150 PM PST Fri Mar 6 2026 (Saturday night through next Thursday)

By the time we get late into the weekend and into early next week, the pattern will shift. The stout high will retreat farther offshore, the upper trough over the Southwest will pinch off into a cutoff low over Northern Baja, and a bagginess in the jet stream will start to encroach upon the Northern portions of our service area. This will be short lived though as high pressure starts to reassert itself during the middle of next week. Model really start to diverge late next week with a few going back to a trough and bringing the area a chance of rain and several others holding on to the ridge and maintaining the string of sunny days. As we get through the weekend we'll have more to say about late next week.

AVIATION
(00Z TAFS)
Issued at 353 PM PST Fri Mar 6 2026

VFR is forecast to prevail with largely N'ly winds through the TAF cycle. Wind gusts at or above 25 knots are forecast to subside at KAPC and KSTS over the next 2-3 hours. While surface winds will subside, they should remain elevated to mitigate LLWS, but trends will be monitored for possible inclusion in future TAFs.
Through the day on Saturday, model guidance largely advertises 10 to 15 knot N'ly winds with some of the higher end guidance suggesting 30 knot wind gusts after 21Z Saturday. For now, will omit gusts given the low confidence for now.

Vicinity of SFO...VFR with WNW winds becoming N-NE'ly through the TAF period. Speeds are anticipated to peak around 10-12 knots. A gust or two above 20 knots cannot be ruled out, but limited duration precludes mentioning in the current TAF. These N-NE'ly winds will persist a little longer than usual, but speeds are anticipated to remain low enough to mitigate any crosswind issues. The LLWS potential appears minimal, but non-zero. For now, will omit this from the TAF and monitor trends in profilers and model guidance.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Light northwesterly winds in the 3-6 kt range are forecast this afternoon. In the evening and nighttime, winds are expected to shift to an offshore direction maintaining its speed. At the later end of the TAF period, there is some potential for some high level clouds, though we still anticipate VFR conditions to persist at both airports.

MARINE
(Today through Wednesday)
Issued at 152 PM PST Fri Mar 6 2026

Hazardous conditions will continue through this evening due to strong northerly breezes and rough to very rough seas. Frequent gale force gusts are expected to continue across the northern outer waters through this evening. Conditions will briefly improve this weekend as northerly breezes diminish and seas subside, yet hazardous conditions will linger for the northern outer waters. By Monday, strong northerly breezes and rough to very rough seas return.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory until 9 PM PST this evening 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.

Gale Warning until 3 AM PST Saturday for Pt Arena to Pt Reyes 10- 60 NM.

Small Craft Advisory until 3 AM PST Saturday for Pigeon Pt to Pt Pinos 10-60 NM.