textproduct: San Joaquin Valley

KEY MESSAGES

1. Lake Wind Advisory continues for West Side Coastal Mountains north of 198 and San Luis Reservoir through 11 PM PDT Tuesday, July 7th. Beware of unsettled waters.

2. Chance of thunderstorms across the Sierra Crest Monday afternoon.

3. Slow but steady warmup next week, with Heat Risk reaching elevated to major levels by weekend.

4. Dry and breezy conditions create elevated fire risk into next week, especially in the Mojave Desert.

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

DISCUSSION

As we get into July properly, the temperatures will begin to reflect that. There is good agreement between models about a ridge beginning to build over the desert Southwest. As such, the San Joaquin Valley (SJV) will have a steady warm up into these warm temperatures. Today, there is only a 15% Probability of Exceedance (PoE) of reaching 100 degrees in the Bakersfield area. The northern portion of the SJV is at less than 5%. Though, the Mojave Desert is at a 80-95%, with California City being at 80% and Ridgecrest at 95. There is a PoE of reaching 105 degrees of only 15%, thus the hottest places today will not exceed 105 degrees.

With this steady warm up, the SJV will see the PoE of reaching 100 degrees become more widespread, yet remain low (>20%) through Wednesday. By Thursday, the PoE of reaching 100 degrees is between 25-50% for the northern SJV, while the southern portion is at 50-75%. Friday is shaping to be the hottest day this week, as the PoE expands to be 50% in Merced county, but 65-80% for the rest of the northern SJV. The southern SJV is currently at 90-95% for Friday's PoE of 100 degrees. The PoE of exceeding 105 in the southern SJV is currently at 25-40%, so there exists a chance of exceeding 105. Looking at the 10th-90th% range, there is a 10% chance of Bakersfield exceeding 108 degrees on Friday. That is the most extreme scenario on deck, currently.

Thanks to the passing shortwave yesterday (remnants of tropical storm Douglas), there is a thunderstorm chance all throughout the Sierra Nevada today. Between 2,200 feet and 5,300 feet in elevation, there exists a 4-8 percent of thunderstorms. Elevations above 7,000 feet (and Yosemite NP) will see a 10% chance of thunderstorms. Elevations higher than 9,000 feet will see a 20% chance of thunderstorms today. The probability of thunderstorms will drop significantly tomorrow and the rest of the week as moisture leaves the area.

Looking ahead into the future, Day 8 Models (Monday, July 13th) are hinting at a similar story. There is a 90% chance of exceeding temperatures in the mid to high 90s for the entire SJV, with a 10% chance of exceeding 105-107 degrees, with the north portion SJV being at 105 degrees and the south at 107 degrees. Ensembles are beginning to show a high pressure system set up north of the Four Corners region, which'll aid in these hot temperatures. The CPC's 6-10 day outlook has the SJV within a 50-60% probability of above average temperatures, as does the 8-14 day outlook. With the positioning of the high pressure, it'll help surge monsoonal moisture into the SJV as well, as the 6-10 day outlook has the SJV in both the 33-40% and 40-50% above average precipitation. The 8-14 day outlook having the entire SJV in a 40-50% above average precipitation. Nevertheless, we are really starting to get into the dog days of summer.

With these increasing temperatures, most areas will be under a moderate (level 2) HeatRisk on Friday, with a few pockets of major (level 3) HeatRisk. Take precautions to ensure proper cooling for you, your neighbors, and pets.

Water temperatures are still in the upper 60s and low 70s and much colder near water flowing from higher elevations. Exercise cold water safety at all times.

AVIATION

VFR conditions expected across the area for the next 24 hours. Gusty winds, brief heavy rain, and lightning in and near Mountain thunderstorms from 20Z Monday through 03Z 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 high.

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

Lake Wind Advisory until 11 PM PDT Tuesday for CAZ300.