Marine Weather and Tide Forecast for Danville, CA

UPDATE
Issued at 844 PM PDT Mon Apr 28 2025

No updates to the forecast this evening. The gradual warmup through midweek remains on track with temperatures closer to normal for the end of the week into next weekend. We're keeping an eye on the potential for a relatively short window of gusty onshore winds Friday afternoon/evening.

SHORT TERM
(This evening through Tuesday)
Issued at 1214 PM PDT Mon Apr 28 2025

Quintessential summer-like pattern setting up early this week in the wake of a soggy weekend. Brilliant visible satellite picture this afternoon showing mostly clear skies with a hint of cumulus over some of the higher terrain. Peaking out the window here at our Monterey office, we can see some of the Cumulus to our north over the Santa Cruz Mtns. All in all not too impressive, and they will stay that way thanks to building high pressure over the northeast Pacific promoting compressional warming aloft and large scale subsidence. More of the same tomorrow, perhaps even fewer clouds during the afternoon. The subsidence of the high pressure aloft and onshore wind will aid in the development of a strong marine layer, which will allow our typical stratus and fog conditions to flourish during the overnight and morning hours.

LONG TERM
(Tuesday night through next Sunday)
Issued at 1214 PM PDT Mon Apr 28 2025

The aforementioned fair weather conditions will prevail through much of this week. The peak of temperatures will likely be Tuesday and Wednesday where highs will be in the upper 70s to near 80 for most inland locations. Coastal areas holding on to the marine layer influence will still be warm and clear, but more like the 60s to lower 70s. The pattern changes by the weekend when a progressive open wave is progged to move into the PNW. This will bring much cooler temperatures and light rain by Saturday and gusty conditions beginning Friday afternoon through Sunday morning. Stay tuned for further updates on timing.

AVIATION
(00Z TAFS)
Issued at 424 PM PDT Mon Apr 28 2025

Generally VFR conditions continue through the evening with patchy stratus at the immediate coast, especially on the San Mateo Peninsula. Expected compression of the marine layer will limit the inland expansion of stratus tonight. Low confidence in model solutions that bring stratus to LVK and SJC, but have kept SCT groups at both terminals. Clearing begins around 17-19Z, with most terminals clearing out a few hours later as patchy stratus persists at the immediate coast. Moderately breezy onshore winds continue through the evening, with light and variable winds overnight before breezy onshore winds resume Tuesday afternoon.

Vicinity of SFO...VFR through the evening with moderate to high confidence in MVFR conditions coming in sometime overnight. Main source of uncertainty is the potential compression of the marine layer, as if the marine layer compresses more than the current forecast, it could limit the potential cloud cover at SFO.
Clearing of any ceilings should take place over Tuesday morning.
Moderately breezy onshore flow should continue into the evening, turning light overnight before resuming Tuesday afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR at present, expected to continue into the evening. Low confidence in the timing of stratus development at MRY. Models are trying to push back the stratus development time to around 08-09Z, but with high resolution ensembles still hinting at an early return and lingering stratus clouds in the terminal area, opted to retain the earlier forecast for this TAF.
May need to adjust if the stratus does clear out or if model agreement on a later development of stratus becomes stronger.
Clearing is expected near 17-18Z with the potential for lingering clouds or perhaps an early return (near or shortly after the end of the TAF period) at MRY. Moderately breezy onshore winds continue through the evening, light variable or drainage winds overnight before the onshore flow resumes Tuesday afternoon.

MARINE
(Tonight through next Sunday)
Issued at 844 PM PDT Mon Apr 28 2025

Fresh to strong north to northwest winds continue over the coastal waters through Wednesday as high pressure builds. Near gale force gusts are expected over the far outer coastal waters.
Probabilistic guidance shows a 30 to 40% chance of gale force gusts occurring over the far northern outer waters. Moderate seas are expected over the outer waters as wave heights build to 8 to 11 feet. Winds diminish midweek before another, deeper, upper level trough and surface cold front moves across the coastal waters and bays late Friday with strong winds and hazardous marine conditions returning into the weekend.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory from 3 PM to 9 PM PDT Tuesday for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 9 PM PDT this evening for Pt Pinos to Pt Piedras Blancas 0-10 nm.

Small Craft Advisory until 9 PM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM.