textproduct: San Joaquin Valley

KEY MESSAGES

1. Temperatures will remain above average through the weekend.

2. Gusty winds tonight through early Thursday morning along the Mojave Desert slopes and through the weekend.

3. Practice cold water safety, as waterways will be running cold and fast over the next several days.

4. Confidence is increasing regarding Sierra Nevada precipitation by Monday.

DISCUSSION

A slight cooldown is in store for Thursday as the upper level synoptic pattern shifts towards zonal flow, however prevailing flow will quickly shift to the southwest, creating another warmup into the weekend. Ensemble guidance from the NBM expresses an 80 to 90 percent probability for temperatures to rise above 85 degrees in the San Joaquin Valley on Sunday. Beforehand, this evening into Thursday morning, a small localized area of low pressure is expected to push through southern California and into portions of the southern San Joaquin Valley, resulting in stronger wind gusts particularly along the Mojave Desert Slopes as southerly winds move cyclonically around the system.

Confidence is growing in a pattern change for next week, caused by a longwave trough pushing into the western US late Monday into early Tuesday morning. THe highlight from this pattern change is the return of precipiation to portions of the valley areas and snowfall to the Sierra Nevada. Over a 24 hour period ending next Wednesday at 5 AM, there is a 40 to 50 percent probability for the northern San Joaquin Valley to recieve 0.1" of rainfall, with a 30 to 40 percent probability for the southern San Joaquin Valley. Over the same time frame, there is a 50 to 60 percent probability for at least 2 inches of snowfall in the Sierra Nevada with snow levels projected between 7500-8000 feet.

FIRE WEATHER

A drop in temperatures is expected for Thursday before temps rise with a warming trend into the weekend. RH values will rise, then fall again as a result, curing fine fuels across the region. 100- and 1000- hour fuels will continue to trend drier but remaining below critical thresholds for this time of year. No precipitation is expected through the weekend.

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

Wind Advisory until 5 AM PDT Thursday for CAZ338.