, Issued at 235 PM PDT Sun Apr 19 2026 (This evening through Monday)
Pleasant end to the weekend for the Bay Area and Central Coast weather wise with filtered sunshine and seasonably mild temperatures. Max temps today will peak in the 60s to mid 70s with a few interior spots making a run at 80 plus.
Stepping back and taking look at the bigger picture reveals a system lurking off the coast. In fact, pretty impressive looking visible satellite imagery this afternoon. A discernible circulation is spinning off the PacNW with a band of clouds wrapping around the system and stretching along the West Coast. The circulation is an anomalously deep upper low. At the surface is a double barrel low pressure system with a marked frontal structure. The surface low and front will begin to inch its way eastward Sunday evening and Sunday night. The advancing cold front will bring increasing clouds and a few scout showers to the northern coastal waters and far northern Sonoma county. Not expecting much in the way of accumulating precip with these leading showers through Sunday night.
More widespread precip is expected on Monday as the highly amplified upper jet begins to phase off the CA coast. Light to moderate rain will begin across the North Bay toward the end of the AM commute. Rain will spread S and E through the day with the passage of the cold front. Expect the evening commute to be pretty messy with wet roads.
In addition to the rain on Monday, southerly flow will ramp thanks to a tightening surface gradient. Winds are initially strongest over the waters before hitting the coast and inland areas by the afternoon. Not strong enough for a wind advisory, but general gusts in the 30-40 mph range seems reasonable. Given the southerly flow, initial rain chances for some areas will be eaten thanks to downslope flow and rain shadowing.
As for temperatures, despite a pattern change temperatures will be mild since the region will be in a warmer sector until fropa. Given the solid S flow think there could be some enhanced downslope warming - thinking Monterey.
..issued at 238 PM PDT Sun Apr 19 2026 (Monday night through next Saturday)
Monday looks wet, but Tuesday may end up being a little more dynamic thanks to convection. A few things we'll be watching for Tuesday: cold pool aloft behind the front destabilizing the atmosphere, approaching upper low, position of left exit of jet aloft, and wind profiles relating to low level shear. While those pieces varying from model to model, enough of a signal is present to justify having thunderstorms in the forecast for Tuesday. Putting things into better context, the ECMWF Extreme Forecast Index has strong signal for CAPE over the coastal waters giving more confidence to thunderstorms. SPC Day 3 outlook does have the entire region in a general mention of thunderstorms.
Monday's rain and Tuesday additional shower activity should be mostly beneficial rain, but given the convective nature local ponding/minor flooding is possible. Lingering showers will continue into Wednesday afternoon thanks to a trailing shortwave behind the departing upper level low/trough.
Warmer and drier conditions there after.
(06z TAFS) Issued at 937 PM PDT Sun Apr 19 2026
The slow moving cold front continues to creep towards the coast. SE winds ahead of the front have dropped the dew points to remarkably low values across the interior terminals. SJC is currently reporting a dew point of 8 degrees celsius! While this dry air will not be enough to stop the incoming rain, it will help keep ceilings and visibility in the VFR category until it gets here tomorrow.
Vicinity of SFO, There is virtually no chance for visibility or ceiling impacts before 12Z. Monday will bring moderate southerly or SW winds that will likely be strong enough to impact the runway configuration at times. Rain is set to arrive in earnest around 21Z with frontal passage early Tuesday morning.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, The front is creeping very slowly and impacts will take longer to reach the southern terminals. The best chance for rain onset is Monday evening.
(tonight through next Saturday) Issued at 937 PM PDT Sun Apr 19 2026
Prefrontal southerly winds will increase to a strong breeze through the morning before the front passes and winds shift to a moderate SW'rly breeze by Tuesday. The front will also bring steady rain Monday with showers and possible thunderstorms on Tuesday. As the weather breaks, winds will gradually shift back to the standard NW direction Wednesday before increasing to a strong NW breeze by Thursday.
Ca, None. PZ, Small Craft Advisory from 9 AM to 9 PM PDT Monday for SF Bay N of Bay Bridge.
Small Craft Advisory from 9 AM Monday to 3 AM PDT Tuesday for Mry Bay.
Small Craft Advisory from 3 AM to 9 PM PDT Monday for 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 Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory from 3 AM Monday to 3 AM PDT Tuesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.
