textproduct: San Joaquin Valley

KEY MESSAGES

1. A warming trend continues through much of the week.

2. Minor Heat Risk expected for the lower elevations of Central California.

3. Areas of Moderate Heat Risk expanding across the San Joaquin Valley and Mojave Desert toward the middle of the Week.

4. Slight chance of showers and thunderstorms along the Sierra Nevada crest during the next few days.

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

DISCUSSION

With the ridge of high pressure dominating the West, maximum temperatures will continue to war. Temperatures this Monday were well into the 90s and will continue to rise into Tuesday. With temperature trends aiming upward, we will see more spots approach the upper 90 degree mark. Probability of Exceedance (PoE) of reaching 95 degrees will range from 20-40 percent over the northern portions of the district (Central San Joaquin Valley) and between 40-70 percent across the Southern San Joaquin Valley. Ensemble upper-air analysis has the axis of the ridge of higher pressure over California on Tuesday and pushing over the Great Basin around Wednesday. With this, support is increasing the Tuesday and Wednesday will see additional warming as PoE of 95 degrees moves up into the 60-80 percent range. Yet, the PoE of reaching 100 degrees is still only in the 5-15 percent range this week. Therefore, out-side of the Mojave Desert, the valley may find it difficult to reach triple digit heat.

Although a disturbance will move across the Pacific Northwest around the middle of the week, minimal effects will be felt over Central California. The shift in the weather pattern toward a slight zonal flow will prevent temperatures from reaching 100 degrees. While still hot, the flow pattern will keep the region closer to normal. Looking toward the longer term periods, ensemble consensus analysis does show a change toward a disturbance entering the region next weekend. Current trajectory has it pushing through the Pacific Northwest as main affect for Central California will be a change in temperatures.

Humidity will lower as it coincides with temperature rises this week. The warming conditions will lead to isolated convection over the Sierra Nevada Crest as the probability of Thunder rise to near 10 percent on Tuesday. Latest CPC outlooks show near normal conditions early in the period and then lean toward a likely probability of above normal temperatures in the 8-14 day period. Precipitation will range from near average in the early 6-10 period with leaning below normal in the 8-14 day period.

AVIATION

VFR conditions expected across the central California interior for 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 and/or to provide feedback.

HNX WATCHES/WARNINGS/ADVISORIES

None.