, Issued at 1152 AM PDT Tue Mar 31 2026 (This afternoon through Thursday morning)
It only took 29 days, but it's finally raining. A stationary front is offering an area of convergence for its tropical moisture tap. Rain shower activity will continue to drift south through the day as surface high pressure tries to nose in from the Eastern Pacific Ocean. A gale force low in the Gulf of Alaska will put a stop to that as it heads to the Washington/Canada border. The attendant cold front will bring us a winter-like feel with below normal temperatures, gusty conditions, and rain. Southwesterly winds will increase ahead of the cold front with northwesterly winds developing in the post-frontal environment. Widespread gusts of 20-30 mph can be expected with gusts up to 40 mph in the highest terrain. Rainfall totals are expected to be in the 0.10"-0.25" range with locally higher totals in the higher terrain of the North Bay and locally lower totals in the Interior Central Coast. Slick roadways can be expected due to the dry spell that has allowed oil to accumulate.
..issued at 1152 AM PDT Tue Mar 31 2026 (Thursday night through next Monday)
The pattern will quickly change Thursday afternoon as upper-level shortwave ridging noses in from the Eastern Pacific Ocean. The short wavelength of the aforementioned trough and ridge will tighten the pressure gradient. Strong northerly winds will result, primarily affecting exposed areas like the higher terrain and marine environment. The SFO-WMC pressure gradient is expected to become negative Thursday night as the wavelength moves inland, resulting in offshore flow. At 5 AM Friday, the ECMWF Ensemble mean is forecasting the gradient to be -9.81 mb while the GEFS mean is forecasting the gradient to be -7.76 mb. The 2 mb discrepancy is due to the ECMWF Ensemble showing a stronger high and stronger low closer together than weaker features farther apart in the GEFS. This uncertainty is propagated through Friday and Saturday with the ECMWF Ensemble bottoming out at -10.96 mb at 5 AM Saturday while the GEFS is well on its relaxing trend at -5.24 mb. Nonetheless, a moderate offshore flow event can be expected Thursday night through the weekend with a 35 knot 925 millibar jet streak across the North Bay. This will translate to gusts of 40 to 50 mph in the higher terrain, namely the North Bay Interior Mountains, East Bay Hills, and Eastern Santa Clara Hills. The ridge will also send temperatures soaring back to well above normal.
(06z TAFS) Issued at 939 PM PDT Tue Mar 31 2026
VFR is expected to prevail until early Wednesday morning in the wake of scattered showers across our area earlier today. One exception is KAPC that is already MVFR and is expected to remain so through the forecast period. KSTS will follow suit later during the overnight hours.
Vicinity of SFO, Bay Area terminals are expected to be VFR until later in the overnight hours when cigs drop to MVFR and are expected to remain MVFR through the remainder of the forecast period. Light rain will increase in coverage from late morning through the afternoon hours with breezy southwest winds out ahead of a cold front that arrives later Wednesday night.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR is expected to prevail through the forecast period with a chance of MVFR cigs in the hours surrounding sunrise. There is a slight chance of light rain late in the TAF period but confidence is too low for mention in the TAF attm.
(tonight through next Monday) Issued at 939 PM PDT Tue Mar 31 2026
Fresh to moderate southwesterly breezes tonight out ahead of a cold front will become northwest behind the cold front as it passes through our area late in the day Wednesday into the evening hours. Strong northerly breezes will develop by Thursday afternoon and persist through Friday with moderate seas building to become rough with widespread hazardous conditions. Conditions improve for the weekend.
Ca, None. PZ, Small Craft Advisory from 3 PM Wednesday to 3 AM PDT Friday for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.
