National Weather Service - Discussion

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Area Forecast Discussion

National Weather Service - San Joaquin Valley / Hanford, CA
Issued: Sunday, April 11 2021 - 1:45 AM PDT

SYNOPSIS... Well above average temperatures today and tomorrow as the ridge of high pressure aloft remains in place. A trough of low pressure is forecast to enter the Great Basin on Tuesday, which may lead to isolated snow showers along the Sierra Crests Tuesday and Wednesday afternoons, along with cooler afternoon valley highs. Strong winds will also be likely to occur by Tuesday evening through the Mojave Desert. Warming trend to resume late next week as high pressure builds.

DISCUSSION... Afternoon highs today are forecast to reach into the low 80s across the valley as the ridge of high pressure prevails. Blended model guidance is showing Monday being the warmest day of the week, with highs expected to hit the low to mid 80s across the San Joaquin Valley, which is about 10 degrees above average. Probabilistic data show that there is a 36% chance of the afternoon high in Fresno reaching 85*F and a 42% chance of 85*F in Bakersfield on Monday.

On Tuesday, model guidance is showing a slow-moving trough of low pressure enter the Great Basin, which may trigger an isolated snow shower or two over the High Sierra for Tuesday and Wednesday afternoons. The jet associated with trough may also align itself favorably with the Tehachapi Mountains by Tuesday afternoon, which could support strong winds through and below the mountains passes. Finally, expect a bit of a cool down Tuesday and Wednesday over the area, with afternoon highs retreating into the mid 70's by Wednesday as 500 mb heights fall.

By Thursday, the GEFS and EPS ensemble means are showing the Eastern Pacific ridge of high pressure begin to rebuild over the area, which would mark the start of another warming trend over the area. The ridge is forecast to build through the weekend and may become the dominant synoptic feature over the forecast area for some time. For us, this would mean the continuation of dry weather, with perhaps even higher afternoon highs than we have seen this year in the extended period. This would seem to be supported by the CPC day 8-14 outlook, which favors both above average temperatures and below average precipitation over Central California.

AVIATION...VFR conditions are forecast to prevail across the central CA interior over the next 24 hours.

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 an/or to provide feedback.

HNX WATCHES/WARNINGS/ADVISORIES... None.