Marine Weather and Tide Forecast for Port Costa, CA

DISCUSSION

Today
Warm and dry weather prevails across the area as ridging remains in place. Forecast highs are expected to be in the 70s in the Valley and foothills, and 50s to 70s in the mountains. Patchy fog may develop tonight into Saturday morning, mainly across portions of the southern Sacramento and northern San Joaquin valleys.

...Saturday - Sunday...
Ensemble guidance indicates an upper level low approaching the West Coast and moving into California this weekend into early next week. This will bring showers and thunderstorms to the area with best chances over the northern/central Sacramento Valley and in the foothills and mountains. The National Blend of Models (NBM)
shows roughly a 15-40% chance of thunderstorms on Saturday and a 10-30% chance on Sunday over those aforementioned locations with best chances to see storms from 1 PM - 9 PM, potentially lingering into the overnight hours. Heavy downpours, gusty winds, and potentially severe hail are the main threats with any thunderstorms that develop. Very light high elevation mountain snow is possible above 6500 feet late Sunday into Monday, with amounts generally less than 2 inches at the highest peaks.

Warmer than average temperatures are also favored to continue over this timeframe with highs generally in the 60s to 70s in the Valley and foothills, and 50s to 70s in the mountains.

...Monday-Tuesday...
Lingering showers are expected over the Sierra through Monday, otherwise dry weather is anticipated as ridging builds back into the region briefly. Afternoon highs in the 60s throughout the Valley with fairly quiet weather.

Mid to Late Week
A trough moving into the Pacific Northwest clips the area by mid- week, bringing some light showers to the northern Sacramento Valley, foothills and mountains north of Highway 50 on Wednesday.
Dry conditions return on Thursday, with breezy north to east winds developing behind the system. NBM probabilities of wind gusts greater than 30 mph sit around 50-70% for Thursday, with the highest chances along and west of I-5 and mountains.


AVIATION

General VFR conditions with light north to east winds until 06z Saturday before patchy MVFR conditions from mist with a low chance of IFR to LIFR conditions impacting the Sacramento area (SMF, MCC, MHR, and SAC) from 10z to 15z Saturday. Chances for vicinity showers over N Sac Valley (KRDD) near 18z Saturday ahead scattered showers and thunderstorms afterwards.

STO WATCHES/WARNINGS/ADVISORIES
None.