Marine Weather and Tide Forecast for Mountain House, CA

SHORT TERM
Issued at 1201 AM PDT Mon Aug 17 2026 (Today and tonight)

Quiet weather today with little to no impactful weather expected through the next week. Temperatures today will be near or slightly below normal for this time of year with slightly more mild overnight lows to wake up to this morning than we've seen the last few days due to mid/high level cloud cover insulating radiative cooling. The mid to high level cloud cover will continue out ahead of a persistent troughing pattern over the EPAC. The additional cloud cover may impact daytime highs as well, limiting peak day heating somewhat. Some patchy fog and drizzle may be possible as well, especially right along the coastline.

LONG TERM
Issued at 1201 AM PDT Mon Aug 17 2026 (Tuesday through Sunday)

Slight shifting in the persistent troughing over the EPAC and the upper level ridging over the Four Corners region will result in subtle warming Tuesday and Wednesday, as the upper ridge pushes west slightly. The troughing pushes back to the east for the remainder of the week, cooling temperatures a few degrees.
Overall, temperatures will be on the cooler side of normal for a majority of forecast period. There is no clear signal for a significant pattern change through the extended forecast.

AVIATION
(12Z TAFS)
Issued at 416 AM PDT Mon Aug 17 2026

High clouds and stratus are pushing into the Bay Area and Central Coast this morning. Stratus coverage is less expansive today than it has been over the previous two days with the marine layer having compressed to approx. 1000 ft. This is bringing IFR conditions to interior sites with LIFR conditions along the coast. Coastal fog is possible with buoys supporting an upwards transport of moisture offshore (a better environment for fog development). Conditions improve by late morning with interior sites to see VFR conditions this afternoon into the evening.
Coastal sites are a little trickier as stratus is forecast to hug the shoreline through the day which may result in patchy stratus intrusions at coastal sites during the afternoon. Kept HAF overcast through the entire day but BKN/OVC ceilings may briefly scatter out during the late morning/early afternoon. MRY and SNS are more likely to clear out today but cloud cover is expected to return during the early evening.

Vicinity of SFO...Stratus is visible on camera approaching SFO but confidence is low as to the exact timing/duration of the stratus.
The current TAF has a tempo in through 16Z for patchy stratus but this may need to be extended through 18Z (which ensembles suggest as a reasonable late clearing time for today). Given that the marine layer will be compressed again tonight, I pushed back the timing for stratus return tonight to closer to 10Z. Confidence is low to moderate on timing given that stratus is expected to be patchy again tonight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR-LIFR ceilings continue through late morning before a brief period of VFR conditions returns this afternoon. This is short lived with IFR-LIFR conditions returning shortly after 00Z. Reductions in visibility become more likely towards the end of the TAF period with a low potential for fog to develop at both sites. Breezy onshore winds return during the afternoon and evening before winds decrease overnight.

MARINE
(Today through Saturday)
Issued at 416 AM PDT Mon Aug 17 2026

Winds gradually increase today with a fresh to strong breeze developing by late tonight and continuing through the end of the forecast period. Locally stronger winds are possible in the coastal jet regions north of Point Reyes and along the Big Sur coast. Seas build to 7 to 9 feet by Tuesday and Wednesday before abating late week. A long period southerly swell around 14 to 15 seconds will continue to subside through the early work week.

FIRE WEATHER
Issued at 1205 AM PDT Mon Aug 17 2026

Nocturnal drying through at least mid-week as the marine layer gradually compresses. Expect more widespread fair to moderate recoveries developing over the higher elevations, especially in and around the Timber Fire.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory from 3 AM to 3 PM PDT Tuesday for Pt Arena to Pt Reyes 10-60 NM.