As we approach the weekend, the National Weather Service brings a positive outlook for weather conditions, anticipating pleasant weather and clearing skies through the weekend and early next week throughout the Bay Area.
However, cooler overnight temperatures are expected Sunday into midweek, setting the stage for potential changes in weather patterns.
The latest update from the National Weather Service indicates that a cold front is currently moving southeastward across the forecast area. Earlier Friday evening, San Francisco International Airport experienced a peak wind gust of 30 knots (35 mph), though winds have since diminished.
Some areas of low clouds have developed due to a combination of factors, including nocturnal radiative cooling, cool air advection, and upslope cooling.
With diminishing surface winds overnight, patchy fog may develop early Saturday morning, potentially impacting visibility.
Friday saw temperatures above to well above normal, with one record high temperature tied at San Jose. The high temperature of 67°F tied records from 2013, 1999, and 1919. Looking ahead, daytime high temperatures are expected to cool back to near late December normals during the weekend. Night and morning temperatures will also cool, ranging from the 30s in inland valleys to the lower to mid-40s near the coast and bays.
Clear and mild conditions are expected going into the weekend as weak ridging builds behind a departing upper low.
The passage of a weak, dry frontal boundary has effectively cleared out fog and most cloud cover for the day. Saturday will see the full development of ridging, bringing clear skies and cooler temperatures.
The coolest temperatures of the forecast period are anticipated Saturday night into Sunday morning, with overnight lows ranging from the mid-30s to lower 40s for most locations.
A weak shortwave trough around the periphery of a deep upper low in the Gulf of Alaska may slightly flatten the ridge late Sunday, with the possibility of a few showers in northern Sonoma County and coastal Marin.
Looking further into the week, the National Weather Service anticipates the approach of the next storm system, potentially bringing rain chances by midweek.
Ensemble guidance suggests the main upper low moving from the Gulf of Alaska into the West Coast by Tuesday, with uncertainty remaining about the extent of rainfall.
Confidence will increase as the event approaches, and additional updates will be provided as the model guidance refines the evolving features of this upcoming weather system.
