textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 911 PM PDT Wed Mar 25 2026

- Above normal temperatures persist into the weekend

- Offshore winds across the North Bay Interior Mountains thru Friday

- Pattern change with chances for largely beneficial rain next week

SHORT TERM

Issued at 911 PM PDT Wed Mar 25 2026 (Tonight through Friday)

Generally quiescent conditions are forecast during the short term period, with the exception being across some of the higher terrain of the North Bay Interior Mountains as well as parts of the East Bay Hills tonight, but especially pre-dawn Friday morning.

A dry/cool frontal boundary continues to slide southward through portions of the North Bay this evening, with a pretty discernible northerly wind shift evident on observations upstream across Lake and Mendocino Counties. This frontal boundary will usher in some cooler air and as noted previously, min temperatures should be a touch cooler (at least across the North Bay), but sunrise Thursday compared to the past few days. Overall, not anticipating a potential for widespread frost/freeze conditions, though a few spots may dip down into the upper 30s across extreme northern Sonoma and Napa Counties.

925mb flow does increase some on Thursday morning, in the immediate wake of the front, but the real potential for any type of mountain wave activity is greater on Friday morning. This will be due to building high pressure in the wake of the front through the day on Thursday. As the MSLP gradient tightens beneath a largely stable regime, flow will become trapped and forced around the complex terrain. Areas such as Mt. St. Helena and other peaks across the North Bay Mountains may see winds gust as great as 45 mph pre-dawn Friday morning. The SJSU/PG&E WRF as well as our in- house model highlight this potential well.

Otherwise, mid/upper level clouds will continue to invade from the southwest resulting in partly sunny skies. Despite largely filtered sunshine, high temperatures will remain 10 to 15 degrees above normal. This trend will continue through the weekend.

LONG TERM

Issued at 911 PM PDT Wed Mar 25 2026 (Friday night through next Wednesday)

The weekend is anticipated to be quite pleasant. With the magnitude of offshore flow weakening slightly, this may allow for the afternoon sea-breeze to bring MaxTs down a few degrees compared to the previous days. Still highs are expected to remain 5 to 10 degrees above normal.

Our ridge pattern that has resulted in our well above normal heat will yield to more pronounced troughing as we venture into next week. There do remain some temporal and spatial differences in the placement of more vigorous shortwaves in the longwave trough and we'll continue to examine the latest guidance as it arrives for next week.

Some of the synoptic scale progs from the deterministic guidance advertise swift mid-level flow extending from the southwest with favored large scale ascent beneath the exit region of a 50 knot jet. This will equate to cooler conditions next week. At this time, Monday appears largely precipitation-free and this is a slight change from previous forecast cycles due to a slower evolution of the upper trough as it amplifies across the West Coast. Overall, NWP is in fair to good agreement with this feature. After a few days of troughing, a corridor of 180-200% of normal precipitable water air will stretch from the Central Pacific eastward toward California. Both GEFS and EPS renditions of the probability of Integrated Vapor Transport (a useful tool for quantifying moisture transport) above 250 kilogram/meter/second have gradually increased from less than 10% 72 hours ago to near 50% in the latest guidance. There are some spatial differences among model guidance with regard to the exact location of this plume of rich moisture and thereby the placement of the greatest rainfall and we'll continue to iron out these details through the weekend.

Current forecast rain amounts appear respectable for this time of year, with the greatest potential for at least 1" of rainfall across the North Bay from late Monday into Wednesday. Chances for at least 2" of rainfall (which would be the higher end rain amount) are around 10% across the Western Sonoma Hills, Santa Cruz Mountains, and the Diablo Range. As noted above, once we get closer, we'll be able to refine these rain amounts.

With actual upper level dynamics, surface/low level cyclogenesis appears that it'll give some of the higher terrain and Pacific Coast regions around a 40-70% chance for SW'ly wind gusts near/above 40 mph. Increased onshore flow and subsequent cloud cover will also equate to temperatures being 5 to 15 degrees below normal by the time we get into next week with daytime highs ranging between the mid 50s to mid 60s.

AVIATION

(06Z TAFS) Issued at 957 PM PDT Wed Mar 25 2026

Generally VFR conditions persist overnight with a few high clouds. Lingering westerly flow will diminish into light winds overnight, with some low confidence for stratus development at the immediate coast. Thursday morning, a pulse of gentle north to northwest winds moves through the inland terminals with the rest of the region seeing some onshore winds developing a little later onwards. LLWS is expected to develop in the interior North and East Bay on Thursday evening, as the surface winds decouple from strong northerly flow aloft.

Vicinity of SFO... VFR with a few high clouds through the TAF period. Breezy west-northwest winds continue through the next couple of hours. Winds gradually diminish in the late evening with light winds Thursday morning, before the breezy west-norhtwest winds resume during the afternoon.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... Low confidence for sub-VFR conditions tonight at MRY, not high enough to place a ceiling in the TAF, otherwise VFR throughout the TAF period. Breezy northwest winds at present, with winds turning light over the next couple of hours. Thursday morning, light northerly winds will back to a northwest flow at MRY, with gentle northwest winds through the afternoon at SNS, before winds diminish into the evening.

MARINE

(Tonight through next Tuesday) Issued at 857 PM PDT Wed Mar 25 2026

Northwesterly gales across will persist tonight into Thursday morning across the outer waters and the inner waters north of Pigeon Point. Conditions begin to improve south to north by Thursday evening, persisting over the northern outer waters through Friday afternoon. Wind and seas ease for the weekend, then begin to increase once again by the middle of next week a developing system begins to move toward shore.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Gale Warning until 3 AM PDT Thursday for Pt Arena to Pt Reyes 0- 10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

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

Gale Warning until 9 AM PDT Friday for Pt Arena to Pt Reyes 10- 60 NM.

Gale Warning until 9 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM.