textproduct: San Joaquin Valley

KEY MESSAGES

1. A low pressure system brings chances for more widespread precipitation tonight and tomorrow. There is a 10 to 20 percent chance for thunderstorms from the eastern San Joaquin Valley to the central Sierra Nevada and adjacent foothills.

2. Wind Advisory for the Mojave Slopes and Desert through 5 AM Monday.

3. Slight chances for precipitation continue each day over the higher elevations of the Sierra Nevada until Wednesday, including a 10-20% chance of thunder every day.

4. Warning trend to end next week.

DISCUSSION

Widespread precipitation across the area as a cutoff low slowly pushes its way into central California, resulting in additional chances for precipitation to round the week off. Through 5 PM Sunday, there is a 50 to 80 percent probability for greater than a quarter-inch of rainfall in the eastern San Joaquin Valley. increasing to 80 to 95 percent in the Sierra Nevada from Yosemite NP through the southern Sierra in Tulare County. Probabilities for an inch or more in this area is at 40 to 50 percent. However, with snow levels generally around 7,000 feet today and falling to 5,500 to 6,000 feet tomorrow, much of the precipitation in the mountain areas will be falling as snow. Through 5 AM Sunday, expected snow totals at the higher elevations of the Sierra are between three to six inches.

This system will also bring stronger wind gusts to the region, especially in the Mojave Desert Slopes in the lee side of the Tehachapi Mountain range, beginning this afternoon and lasting through early Monday morning. During this time period, there is a 60 to 80 percent probability for maximum wind gusts to exceed 55 mph and as such, a Wind Advisory has been issued for this area.

Into next week, a series of weak troughs are expected to track through central California, resulting in additional minor chances for precipitation, though mainly confined to the higher elevations of the Sierra Nevadas. Snow levels rising to 8,000 feet on Tuesday will keep much of the potential precipitation as rainfall. The procession of weak troughs will keep the threat of precipitation and lightning in place through much of next week.

A high pressure ridge is favored to build in over the region towards the end of the work week, driving temperatures upward. There is a 70 to 90 percent probability for maximum temepratures to exceed 85 degrees across the Valley and desert areas by next Saturday.

AVIATION

IFR to MVFR conditions at times in showers across the Valley through 15Z. IFR to MVFR conditions over the Sierra Nevada through at least 00Z in showers and clouds. Otherwise, VFR conditions will prevail for the next 24 hours. Winds of 15 to 25 mph in the Mojave Slopes and Desert through 12Z Monday with gusts up to 55 mph.

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 Monday for CAZ337>339.