textproduct: San Joaquin Valley

KEY MESSAGES

1. Precipitation tapering off across the area today, though a chance for thunderstorms remains possible, particularly in the Sierra Nevada, Coastal Range, and foothills.

2. A gradual warming and drying trend expected this week.

3. Another system brings stronger winds and a risk for thunderstorms Thursday.

DISCUSSION

The upper low that brought active weather this weekend is beginning to exit the area, bringing quieter weather with it for the next few days, though a lingering risk of thunderstorms remains across the area today, particularly in the Sierra Nevada, Coastal Range, and foothills. Probability of thunder is 20-30% in the Sierra Nevada and 10-15% across the rest of the area. Conditions remain windy along the Mojave Desert Slopes, with a 30-40% chance of gusts exceeding 55 mph at Walker pass, increasing to 60-70% near Jawbone.

Looking ahead, Tuesday and Wednesday should be mostly quiet as we enter a quasi-zonal pattern with mild ridging, bringing pleasant conditions, with high temperatures in the low- to mid-70s across the Valley. This may cause a minor decrease in air quality Wednesday and Thursday, which may affect sensitive groups.

Models are in good agreement that a shortwave trough moving down the west coast of Canada will begin to turn east across the US on Thursday. There is not yet good agreement on how deep the trough will be and how far south it will dig. Regardless, the system is likely to bring strong winds to most of the region, with a 5-10% chance of lightning in the Sierra Nevadas at the moment. This trough will clear the region quickly, allowing mild ridging and warming temperatures to build back into the weekend before another system approaches the area early next week. This will create a minor heat risk over the weekend.

AVIATION

VFR conditions expected across the area, with local MVFR and IFR in and near thunderstorms. Wind gusts approaching 40 kts in the Mojave Desert Slopes.

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.