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 Sunday, July 5th, beware of unsettled waters.

2. Weak disturbance moving the California will allow for a slight chance of afternoon thunderstorms across the Sierra Nevada Crest on Sunday.

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

4. Near-normal temperatures expected across the area today, then a warming trend over the holiday weekend.

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

DISCUSSION

There is a small disturbance passing through the Central Valley that has brought morning showers to many cities within the San Joaquin Valley (SJV). They're beginning to move north and out of the CWA now, but it was a welcomed sight. By noon, the cloud cover will recede and we'll be back to sunny skies and warm temperatures. This disturbance will have passed through the Central Valley and be out of California by early Monday morning. As it moves through, it's bringing slightly unsettled conditions to the area, resulting in potential for afternoon thunderstorms in the Sierra Nevada Crest. Today, there is an 18% chance of thunderstorms above 9,000ft. There exists a 5-15% chance of thunderstorms from the foothills up to 7,000ft, with the chance for thunderstorms increasing as elevation increases.

By the middle of next week, an area of high pressure has set up over the Four Corners region. This in turn will set up for warm temperatures for the SJV. Currently, the Probability of Exceedance (PoE) of reaching 100 degrees in SJV is less than 20% on Monday. On Tuesday, the PoE is 21% for Bakersfield, but less than 10% for the rest of the SJV. These probabilities continue to rise throughout the week, with Thursday and Friday being the time of highest percentages, thus the hottest days of the week. Current ensemble guidance has high temperatures in the low to mid-100's, but there exists a 10% chance of temperatures in the 107-109 degree range. Because of these temperatures beginning to increase, much of the area will be under a Moderate (Level 2) HeatRisk. There will be pockets of Major (Level 3) HeatRisk potential (22% chance) in metropolitan areas.

The CPC continues to favor above average temperatures for the 6-10 and 8-14 day outlooks. With both these outlooks, they're also favoring above normal precipitation thanks to Monsoonal influence. They also continue to favor Slight Risk (20-40%) for Hazardous temps from the 13th-19th, with the 13th-17th being a Moderate risk (40-60%). Suffice to say that we are beginning to enter the hottest portion of the year.

As temperatures begin to rise and people seek out ways to cool off, please remember that running streams, rivers and lakes will be colder than the air temperature. Follow all posted signage and law enforcement advice regarding waterways. Exercise cold water safety, as even the most experienced swimmers can lose dexterity in cold water.

AVIATION

VFR conditions expected across the area for the next 24 hours, with a broken band of light showers moving through the Valley for the next few hours. Slight chance (10-15%) of thunderstorms along the Sierra Nevada Crest from Tulare County northward between 20Z SUnday and 03Z Monday.

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

Lake Wind Advisory until 11 PM PDT this evening for CAZ300.