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

As the Ridge of High Pressure becomes the dominate feature over the West, Max temperatures will continue to warm. So far this Sunday, while max temperature values approached the 90F-degree mark, some locations across the San Joaquin Valley fell short of reaching 90F-degrees. With temperatures trends aiming upward, will see more spots reach the 90F-degree mark on Monday. Probability of Exceedance (PoE) of reaching 90F-degrees will range from 70-90 percent on Monday, yet, PoE of reaching 95F-degrees falls below 30 percent. Therefore, the rise in temperatures will be slow as Tuesday has a much better chance of reaching 95F-degrees. PoE on Tuesday ranges from 60-80 percent. Ensemble Upper-air analysis has the axis of the ridge of higher pressure well inland and closer to the Great Basin. With this, Wednesday will see additional warming as PoE of 95F-degrees goes above 80 percent. Yet, the PoE of reaching 100F-degrees is still only in the 5-15 percent range. Therefore, out-side of the Mojave Desert, the valley may find it difficult to reach triple digit heat this week.

While a disturbance does move across the Pacific Northwest around the middle of next week, minimal effects will be felt over Central California. The chance in the weather pattern toward a slight zonal flow will inhibit temperatures from reaching the century mark (100F-deg) through the first days of June. However, the ridge will rebound as the heat of seeing temperatures reach into the 90s will remain over the region through at least the end of the week.

Humidity will lower as they coincide with temperature rises this week. The warming conditions will lead toward some isolated Convective showers over the Sierra Nevada Crest as Probability of Thunder rises to near 5-10 percent on Monday and Tuesday Afternoon's. 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.