Issued at 959 PM PST Mon Feb 23 2026
A long fetch of moisture extends from the tropics to northern California and the Pacific Northwest. The precipitable water (pw) on the evening 00z Oakland sounding increased to 0.92" which is just above the 90th percentile in late February. A fair amount of the pw is at or above 9 thousand feet; surface observations show higher based ceilings near 8 to 9 thousand feet, while it is drier below this level and some evaporation of high ceiling based rain is taking place.
The plume of moisture is forecast to shift east and southeastward tonight through Tuesday night, placing our forecast area within a peak of ~ 1.4" to 1.5" pw (near the maximum for Jan and Feb on Oakland soundings since 1948) by later Tuesday. The higher pw corresponds to an area of increasing low level warm air advection (upward vertical motion). This will combine with southwesterly orographic lift (upward forced air parcels expand and cool to saturation) and result in light to moderate rainfall. Otherwise the 500 mb height pattern is broadly anti-cyclonic with 500 mb heights in the 570s range which is usually not too conducive to precipitating. By late Tuesday the focus of pw, low level warm advection and rain chances diminish while shifting southward with a gradual deeper layer wind shift to westerly post cool frontal by Tuesday night. Forecast on is on track, no updates anticipated this evening.
, Issued at 200 PM PST Mon Feb 23 2026 (This evening through Tuesday)
High clouds streaming over the region ahead of the incoming weather system. Comfortable temperatures in the 60s across the region with the thickest clouds over the North Bay. Moist and mild southerly flow this evening in warm frontal structure but no excessively strong winds forecast given the lack of cold advection. A few stray showers late this afternoon and early evening near the Mendocino county line otherwise mainly dry through 10 pm tonight. Warm frontal light rains develop overnight across the North Bay, especially Sonoma county and the coastal hills down to Marin. Clouds and southerly winds will keep temps mainly in the 50s overnight. Wet roads for the early morning commute mainly for areas north of the Golden Gate.
..issued at 200 PM PST Mon Feb 23 2026 (Tuesday night through next Sunday)
Weak to moderate AR and associated warm frontal structure will keep steady rains pointed from San Francisco northward from 12-18z Tuesday morning with the heaviest rains continuing across Sonoma county. Light rain will gradually shift southward across San Mateo county and the Santa Cruz mountains during the day Tuesday with some light rain pushing into the East Bay. The Santa Clara Valley and points southward will see little or no rain with this system on Tuesday. Rain will continue through the evening commute for much of the Bay Area with wet roads but generally light winds. Rainfall totals by late Tuesday night of 1-3 inches for the North Bay with some some localized 4 inch totals in the Sonoma hills and around Mt Tamalpais. Rain amounts around 1 inch in San Franciso/Oakland with amounts tapering off to around 0.25 for San Jose. Santa Cruz mountains may top off around 1.5 inches but the weakening nature of the system looks to keep amounts generally light for the Santa Cruz mountains with only 0.10-0.25 for the Santa Lucia hills in Monterey County. So in general expect beneficial late February rains from this system with the only place for some possible nuisance flooding across portions of Sonoma county. However, no signs of the system stalling or intensifying beyond Tuesday evening so confidence remains high for no widespread flooding impacts.
Any lingering showers end by 12z Weds with perhaps some soupy morning fog in the moist airmass. High pressure then builds with highs warming back into the 60s and lower 70s with mild overnight lows generally in the 50s at least through Saturday.
Next feature of interest is a weak cutoff low that could impact the region later Sunday into Monday. The main impact would to drop temperatures back down to more seasonable levels with a slight chance of instability showers though no significant rainfall is forecast. Long range trends beyond that keep the pattern somewhat active but not seeing any signs of notable March storms or rainfall.
(06z TAFS) Issued at 1005 PM PST Mon Feb 23 2026
VFR continues with areas of light rain in the North Bay. Cloud layers increase tonight with rain spreading southward tonight and Tuesday. Conditions MVFR-VFR Tuesday with southerly winds then winds shifting to westerly Tuesday evening and night.
Vicinity of SFO, VFR tonight, MVFR in rain Tuesday. Wind becoming light southeasterly tonight and Tuesday morning. South-southeasterly wind increasing to 15 to 20 knots Tuesday, decreasing to 10 knots Tuesday evening.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR tonight and Tuesday. VFR with light rain Tuesday night. Light and variable winds becoming southeasterly 5 to 10 knots tonight and early Tuesday. Southeasterly winds 7 to 15 knots Tuesday becoming light and variable Tuesday night.
(tonight through next Sunday) Issued at 902 PM PST Mon Feb 23 2026
Light to moderate rain will spread farther south tonight through Tuesday night. Winds stay breezy then ease by Wednesday. Dry weather prevails late for the second half of the week with light seas.
Ca, None. PZ, Small Craft Advisory until 3 PM PST Tuesday for Pt Arena to Pt Reyes 0-10 nm.
Small Craft Advisory from 3 AM to 3 PM PST Tuesday for Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 PM PST Tuesday for Pt Arena to Pt Reyes 10-60 NM.
