Marine Weather and Tide Forecast for Mayfair, CA

DISCUSSION
A change in the weather is now upon the Central California Interior as a disturbance traversed Northern California. While a few showers managed to extend south into Merced County overnight, some cloud cover and cooler temperatures dominated the change in the weather. In addition, the cooler onshore air is allowing for an increase in Kern County winds as breezy conditions currently exist over the Mojave Desert Slopes of the Tehachapi Range. Will see a continuation of cooling and breezy conditions ahead of the next more significant disturbance expected on Saturday.

Cooling trend and breezy conditions will start the short term as Probability of Exceedance (PoE) of reaching 85 degrees drops to below 30% in the coming days. By Saturday, PoE of reaching 75 degrees is below 10% across the San Joaquin Valley. This drop increases confidence in a significant cool-down by Saturday as temperatures fall some 10 degrees below seasonal normal values.
As the storm exits later in the weekend, temperature begin a rebound and rise to the mid 80s by Tuesday. The PoE of mid 80s jumps up to a range of 40%-60% at that time. As a note, PoE of 90 degrees sits at 50% by next Thursday (implying that the warming will continue). As for the winds, ensemble surface wind analysis shows an increase in gusts over the Mojave Desert as speeds reaching into the upper 30 mph range. At best, will see breezy conditions with max gusts below advisory criteria. PoE of wind gusts above 45 mph sits at 20%-35% for the next 24-36 hours. Saturday looks more promising with PoE of 45 mph winds sitting between 30%-50%. Then, a return to ridge will decrease winds for the remainder of the period.

Longer range upper-air ensemble analysis is leaning toward the introduction of a trough pattern this weekend. While widespread precipitation is very unlikely across most of the San Joaquin Valley, mountain locations have a better chance. Current PoE of measurable precipitation sits at 30%-40% from Merced County toward Yosemite NP on Friday night and 30%-50% on Saturday with near 50% for the higher elevations near Yosemite. Therefore, while confidence on mountain precipitation is growing, valley rain still has high uncertainty south of Fresno County.
Thunderstorms will be a threat this weekend over areas north of Kern/Kings and Tulare. This threat includes the San Joaquin Valley, foothills and Sierra Nevada. In addition, more snow will accompany the rain and thunderstorms as Saturday will look very unsettled. Storm moves out around Sunday with ridging, drying and warming dominating the period from Monday through at least next Thursday.

AVIATION
12Z: VFR conditions will prevail across the central CA interior through the next 24 hours. A very slight chance (10%-20%) of Sierra Nevada thunderstorms from 20Z today through 03Z Thursday.

AIR QUALITY ISSUES
None.

CERTAINTY

The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is medium.

Certainty levels include low
medium
and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback.

HNX WATCHES/WARNINGS/ADVISORIES
None.