Swell Matrix

Area Forecast Discussion

National Weather Service San Francisco CA

436 am PDT Sat may 2 2026

Short Term

, Issued at 143 AM PDT Sat May 2 2026 (Today and tonight)

The upcoming pattern for the weekend and early week will shift over to chillier temperatures and there is a potential for periods of light drizzle and/or rain. A Beach Hazards Statement is in effect this morning through Sunday evening for long period northwesterly swell, an increasing risk of sneaker waves and strong rip currents.

It's a good idea to pay extra attention to our neighboring NWS office's forecasts too since e.g. the pattern may affect travel near and across high mountain passes.

Today and tonight: A 500 mb closed low near the Pacific Northwest will move southward and gradually strengthen. The low is forecast to be located 400 miles west of San Francisco tonight. Out ahead of the low, plenty of clouds will accompany steady cooling through the lower levels today. High temps along the immediate coastline ended up slightly below early May normal highs Friday. The longer clouds linger today the the more difficult it'll be e.g. to warm past the mid to upper 50s today along the immediate coastline. Farther inland it'll be easier to reach the 60s and 70s including possibly a few lower 80s well inland in the afternoon. Low clouds move back inland tonight with temperatures lowering to the 50s and 40s. Spotty light drizzle is possible today and/or tonight, best probability is along the immediate coastline.

Long Term

..issued at 143 AM PDT Sat May 2 2026 (Sunday through Friday)

The 500 mb low is then forecast to move eastward later Sunday and become located over the Central Coast and San Joaquin Valley Monday and Monday night, then forecast to move across southern California Tuesday. A fair amount of dynamic cooling will accompany the 500 mb low for early May as will relatively higher precipitable water (pw) in situ along the west coast; it's residual pw leftover from a recent northward extension far north of Hawaii earlier in the week. The GFS shows up to 0.90" of pw (90th percentile for early May) reaching the Bay Area Monday night and early Tuesday. It's during this time when some model forecasts lean wet and some lean dry. The wet solutions show wetting rain (at least 0.10" or greater) over much of the Bay Area, while drier solutions are closer to a trace to maybe a few hundredths of an inch. It's a low confidence forecast, please stay tuned to the latest updates.

During mid to late week the 500 mb low will have moved eastward away from California. Behind the low, high pressure ridging is forecast to move in. There still may be a weak trough passing across far northern California late next week. Otherwise a dry and warming trend returns.

Aviation

(12z TAFS) Issued at 436 AM PDT Sat May 2 2026

MVFR-IFR CIGs currently being observed at all airports across the board. Model guidance has been trending too low for much of the night (consistently IFR whereas most airports are MVFR) so went slightly more optimistic with prevailing MVFR CIGs through late this morning. Given that most sites are sitting with CIGs around 1000 ft there may be some CIG fluctuations into IFR territory but these are expected to be short lived and not the prevailing ceiling. Moderate confidence in CIGs clearing by late morning with lower confidence for coastal sites (HAF, MRY). A similar ceiling setup looks likely again tonight with CIGs on the MVFR-IFR border. Left CIGs on the MVFR side for tonight given models are trending too low with CIG heights in the short term. Breezy onshore winds return during the afternoon/evening before winds ease again overnight.

Vicinity of SFO, MVFR with a low potential for IFR CIGs to at least temporarily develop this morning. CIGs clear by early afternoon and return during the evening/overnight. Gusty onshore winds redevelop during the afternoon/evening with gusts peaking between 20-25 knots. Winds ease overnight but remain moderate (10-14 knots).

SFO Bridge Approach. Similar to SFO.

Monterey Bay Terminals, CIGs have been bouncing between MVFR and IFR early this morning. Ceilings have recently trended up (slightly) with MVFR CIGs set to prevail through the remainder of the morning. Low to moderate confidence that MVFR CIGs will not clear at MRY today while CIGs briefly clear at SNS during the afternoon. Breezy onshore winds between 10-12 knots are expected during the afternoon before winds ease overnight.

Marine

(today through Thursday) Issued at 436 AM PDT Sat May 2 2026

Fresh to strong NW breeze continues through Saturday morning with winds diminishing, becoming moderate to fresh, this afternoon. Moderate, wind driven, seas between 8 to 10 feet continue across the northern outer waters through this morning. Seas subside Saturday afternoon into Sunday as winds diminish. Moderate seas and a gentle to moderate NW breeze prevail Sunday into the early work week.

Watches, Warnings, Advisories

Ca, Beach Hazards Statement from 11 AM PDT this morning through Sunday evening for CAZ006-505-509-529-530.

PZ, Small Craft Advisory until 9 AM PDT this morning for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena to Pt Reyes 10-60 NM.

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