, Issued at 900 PM PDT Thu Mar 26 2026 (Tonight through Friday Night)
Above normal warmth is anticipated to continue as we end the work-week. The current expectation is that we'll see a modest push of offshore breezes through the pre-dawn hours on Friday. 925mb flow of 20 to 30 knots is forecast to extend from the northern Sacramento Valley southward through the Bay Area and portions of the Central Coast. This could translate to wind gusts at the highest elevations of the North Bay exceeding 35-45 mph thanks to mountain wave activity through sunrise Friday. In addition to the compressional warming associated with offshore wind patterns, the marine layer will remain nearly non-existent. With a dry airmass in place, there should be a large diurnal temperature range with MinT values in the 40s (a few upper 30s cannot be discounted) with Friday afternoon MaxTs in the 70s and 80s, even across coastal regions.
..issued at 900 PM PDT Thu Mar 26 2026 (Saturday through next Thursday)
The weekend will be largely pleasant with the start of our cooling trend expected to commence early next week. Highs on Saturday and Sunday are expected to remain above normal, especially for areas away from the coast. That said, there are some signs that onshore flow may be a *slightly* stronger on Saturday which may equate to MaxTs a few degrees lower than Sunday. In fact, higher resolution NWP from PGE/SJSU WRF hint that a very shallow and compressed marine layer may try to invade coastal regions (Pacific Coast and SF/Monterey Bays) on Saturday with potentially some morning drizzle/patchy fog. We'll fine tune this in future forecasts. By Saturday afternoon, however, most of the shallow moisture should be scoured out with mostly sunny skies. Depending on the breadth/inland extent, this could modulate MaxTs by 2-5 degrees. Still, it'll be largely pleasant on Saturday. Offshore surface to 925mb flow appears more organized on Sunday, and while morning low clouds/fog cannot be discounted during this time,especially along the coast, Sunday for sure looks to be the warmest day this weekend.
After an extended time of above normal warmth, there will be a very noticeable change as unsettled conditions take shape. This will mean opportunities for rainfall and increased onshore winds. Our stubborn area of high pressure will be dislodged eastward by our longwave pattern that is well-advertised by a majority of deterministic and ensemble guidance. There are some differences with respect to the overall amplitude/depth of the upper trough. That said, the greatest spread in the NWP is due to differences in the progression of various upper troughs. What this translates to is high confidence that we'll see widespread cloud cover and rainfall with lower confidence in specific onset/end times.
A discernible plume of precipitable water (above 150% of normal for this time of year) will stretch from the Central Pacific eastward toward the West Coast by the time we get into Monday. Confidence is increasing that a bulk of the more widespread activity will be later Monday and into Tuesday as a ribbon of 50-70 knot mid-level flow develops ahead of a positively titled upper trough. This corridor of greater winds has shifted a bit farther south compared to what was forecast yesterday by NWP. Not surprisingly, the richest plume of moisture appears that it's aimed a bit more at the Central Coast compared to areas north of the Golden Gate. In fact, the latest QPF through Thursday evening has increased across the Santa Lucia Range/Big Sur Coastline while ticking down slightly across the Western Sonoma Hills. This aligns well with both GEFS and EPS probability of Integrated Vapor Transport above 250 kilogram/meter/second maximized south of the Golden Gate (and probably south of Monterey Bay), at least with this initial upper trough on Tuesday.
A second, more compact upper trough will swing through the region early Wednesday. This second opportunity for precipitation will be what allows totals to tick up a little higher across the North Bay. In total, rain amounts across the Coastal Ranges in Sonoma County still have the best chance of eclipsing 1" (around a 40% chance), with the probability of 1" lower farther south. Of course, areas such as the Santa Cruz Mountains and Santa Lucia Range are likely to be the spots where rain totals could rival regions farther north. Instability does build a little bit more with this second system. While the probability of thunder remains around 10%, the convective nature of activity does complicate rain amounts some due to the isolated to scattered nature of precip.
It does appear that ridging will return sometime Thursday and into Friday, but timing of when this trough will progress eastward is highly uncertain. Total rain amounts are forecast to average between one tenth of an inch across inland areas (including the population centers) to half an inch across coastal regions of the Central Coast and portions of the North Bay. As noted above, western Sonoma County will have the best chance for rain amounts at or above 1 inch. It should be restated that if this second system amplifies more than currently anticipated, then the window for rainfall could be extended into Friday which could drive totals upward. Still, rain amounts appear largely beneficial as even the 90th percentile QPF (reasonable-worst case scenario) are largely 1-2" across the region which shouldn't translate to a major flood risk given the recent dry spell.
This second system will have the potential to produce the stronger non-convective winds (largely across the higher terrain) as the breadth of higher momentum resides through the column. Probability of 40 mph winds are around 60-80% across the North Bay Mountains, East Bay Hills, Sonoma Coastal and Gabilan Range(s).
Ridging is expected to return toward the end of next week. At the surface a cold front will slide southward and dry out the low levels. As surface pressures rise across the Great Basin, we may find ourselves in another period with modest offshore winds. We'll examine this a little closer with time.
(06z TAFS) Issued at 948 PM PDT Thu Mar 26 2026
VFR with widespread high clouds across the region. Winds are gradually diminishing in a generally onshore pattern, except in the higher elevations, particularly in the North Bay, where breezy offshore winds persist. Light winds develop overnight, along with LLWS concerns in the interior North and East Bays as the winds aloft remain strong. Widespread onshore flow resumes Friday afternoon. High resolution models depict the return of marine layer stratus Friday night into Saturday morning, although the greatest confidence for impacts, especially for locations away from the immediate coast, comes after the end of the 24-hour TAF period.
Vicinity of SFO, VFR with thin high clouds through the TAF period. Breezy west-northwest winds persist through the evening hours. Winds gradually diminish in the late evening with light winds Friday morning, before the breezy west-northwest winds resume during the afternoon. Beyond the TAF period, monitoring the potential for stratus impacts at the terminal early Saturday morning, although confidence is very low.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Moderate to high confidence of VFR throughout the TAF period. Light drainage winds overnight before breezy northwest winds resume Friday afternoon. Marine layer stratus expected to develop Friday night, but the greatest confidence for impacts to the terminals comes after the end of the TAF period on Saturday morning.
(tonight through next Wednesday) Issued at 948 PM PDT Thu Mar 26 2026
Fresh to strong gusts continue through the far outer waters overnight, diminishing on Friday before strong gusts return to the northern outer waters Friday night. Rough seas will begin to subside into Friday, becoming moderate by the weekend. Relatively light onshore winds develop Friday into the weekend with light rain returning by the middle of next week.
Ca, None. PZ, Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
