Marine Weather and Tide Forecast for Concord, CA

DISCUSSION

Today
There was a very brief period of morning fog around daybreak in the Sacramento metro area and the northern San Joaquin Valley, as well as the Delta. A weak shortwave is brushing through the northern Sacramento Valley and adjacent northern mountains today, bringing light scattered showers in that area. A light dusting of snow is possible over the higher mountains (7000-8000 feet) tonight. Temperatures this afternoon are again quite mild, with Valley, Delta and foothill highs in the mid to upper 60s, and even some lower 70s in a few spots.

Monday through Wednesday
As the shortwave exits overnight into early morning Monday, some breezy northerly winds will develop, with gusts to around 20-25 mph in the Central Valley by afternoon. The northerly winds should limit widespread fog development, though more winds sheltered areas on the eastern side of the Valley could see some patchy dense fog. The best potential for this is over the eastern portion of the northern San Joaquin Valley. Most areas will be dry Monday, with mostly cloudy skies, cooler, more seasonable temperatures. The next system approaches from the eastern Pacific Monday afternoon, with some rain and snow showers developing ahead over the Sierra.

This stronger, more significant trough passes through on Tuesday into early Thursday, bringing widespread rain showers, moderate mountain snow, breezy winds and cooler temperatures Sunday through the middle of next week. This system has trended slower, with the heaviest snow now a little later, expected Tuesday afternoon through the day Wednesday. A Winter Weather Advisory continues to be in effect from 10 pm Monday through 4 pm Wednesday for the northern Sierra and the southern Cascades and Lassen Park above 5000 feet. Snow levels start around 5000 to 6000 feet early Tuesday, dropping to around 4500 feet Wednesday.
Snowfall totals have increased, with 4 to 10 inches above 5000 feet, 10 to 18 inches above 6000 feet, and up to 2 feet possible over higher peaks. Expect delays and chain controls on mountain freeways such as I-80 and US Highway 50. Rainfall amounts in the Valley have recently trended higher are expected to be generally around a half inch to an inch, though they could be locally higher in thunderstorms. This should limit impacts from rainfall to be mainly slippery travel on roads. The latest probability of thunderstorms has increased to 1520 % for Tuesday afternoon through Wednesday, centered over the southern Sacramento Valley, the northern San Joaquin Valley and into the foothills.

Friday and onward

A potentially wetter and colder system arrives Friday through next weekend, which could bring heavy snow. The colder air means lower snow levels, possibly into the upper foothills. With increased travel due to the Presidents Day holiday, next weekend could see significant travel impacts. There remains uncertainty about this storm, especially the timing, which has recently trended a little later more into early the next week. Stay tuned as more details become available!

The Climate Prediction Center 8 to 14 day outlook favors below normal temperatures and above normal precipitation for the February 15th through 21st timeframe, leaning towards the active weather pattern continuing through the 3rd week of February.

[Monday-Wednesday 4PM] Sierra Chances for 4" of Snow or More: 90-100% [Monday-Wednesday 4PM]

Sierra Chances for 8" of Snow orMore:85-95% [Monday-Wednesday 4PM]

Sierra Chances for 12" of Snow or More:50-80%

AVIATION

General VFR conditions continue the rest of today into tonight.
Light rain showers are possible over the northern Sacramento Valley through 06Z this evening as a weak weather system passes through. Increasing northerly winds from the departing weather system should limit dense fog development in the early morning hours, though some areas of MVFR conditions in BR are expected tonight across the southern Sacramento Valley into the northern San Joaquin Valley from mist through 18z Monday. The northern San Joaquin Valley could briefly see conditions worsen to IFR to LIFR conditions around 15-18z Monday. Breezy north winds are possible after 18z Monday, gusting up to around 15-20 kts over the western side of the Sacramento Valley.

STO WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory from 10 PM Monday to 4 PM PST Wednesday for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park.