textproduct: San Joaquin Valley

KEY MESSAGES

1. Minor Heat Risk across the lower elevations of central California through Tuesday with a warming trend starting Wednesday.

2. Strong winds expected for the Mojave Desert Slopes through early Tuesday morning.

3. Widespread Moderate Heat Risk, including triple digit heat, in the lower elevations Thursday until next weekend.

4. Practice safety around lakes, rivers, and streams, as water is still running cold.

DISCUSSION

A period of stagnant air is currently over central Califronia between two low pressure troughs, the first moving northeast into the northern Plains, and the second that will push throuhg the Pacific states in the coming days. West to northwest flow with the trough will keep temperatures across central California near season averages, with highs across the lower elevations in the upper 80s. While temperatures will be near average, these upper level winds are expected to result in continued dry conditions over the region on Monday, especially at lower elevations. MinRH values in the San Joaquin Valley are anticipated less than 20 percent, with Desert RH values under 15 percent. Tuesday will bring a quick influx of moisture, raising dew point temperatures, and as a result, pushing relative humidities above 30 percent for most of the area. The influx is also expected to increase wind gusts across protions of the area, particularly in the Mojave Slopes where there is a 50 to 60 percent chance for wind gusts to exceed 60 mph overnight Monday into Tuesday monring. Because of this, a Wind Advisory has been issued for this area valid through 5 AM Tuesday.

As the aformentioned trough pushes eastward midweek, a warming trend will start, resulting in afternoon highs across the lower elevations to enter the triple-digits. Ensemble guidance expresses a 60 to 70 percent probability for maximum temperatures to exceed 100 degrees both Thursday and Friday. A relative cooldown will develop into next weekend, however there is still a 40 to 50 percent probability for triple-digit temperatures Saturday through Monday. These warmer temperatures will drive another threat for fire danger as relative humidities across the valley areas are projected to be below 15 percent, with 20 percent or less RH values creeping into the lower elevations of the Sierra Foothills.

AVIATION

VFR conditions expected across the central California interior for the next 24 hours. Surface Wind gusts to 40kts over the Mojave Desert slopes in eastern Kern County continue through 12Z Tuesday.

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 Tuesday for CAZ338.