textproduct: San Joaquin Valley

KEY MESSAGES

1. A 5 to 15 percent chance of thunderstorms exists through this evening.

2. Cooler and unsettled weather continues today with snow above 7,000 feet in the Sierra Nevada.

3. A warm up is anticipated late this weekend into early next week with high confidence for at least Moderate Heat Risk in the valley areas.

DISCUSSION

The upper-level low pressure system that has been bringing us cooler, unsettled weather is currently centered over the Southern CA coast and will continue to move inland today. This feature will continue to bring a chance of showers and thunderstorms over mainly the Sierra Nevada through this evening. Storm movement will generally be from the northeast due to the position of the low. High pressure ridging will build into the region by Thursday. In the meantime, expect cooler than average temperatures to continue today with a return to seasonal temperatures Wednesday.

The ridge will strengthen further over much of the Golden State on Friday into next week. Above average temperatures return, but will be similar to late last week's initially. For Sunday until at least next Tuesday, even hotter temperatures are in store. Triple digit heat has a low to moderate probability (20-30 percent chance) on Sunday in the warmest locations in the San Joaquin Valley and Kern County desert. There is a 65 to 75 percent probability of seeing our first widespread triple digit highs in the Central Valley and a 50 to 60 percent chance for the Kern County desert by Monday. This will be a significant change from what we have seen in recent days!

Latest CPC outlooks show a high probability of above average temperatures (at least 60-70 percent chance for the 8-14 day outlook and 80-90 percent for the 6-10 day outlook) and below to near average precipitation (or around a 40 percent chance of below average for the 6-10 day period and near average for the 8-14 day outlook) for the middle part of this month.

AVIATION

VFR conditions will prevail for the next 24 hours over Central California. However, up to a 15 percent chance of thunderstorms exists over the Sierra Nevada until 03Z Wednesday, where MVFR and IFR conditions can be expected. Also, MVFR to IFR conditions will continue over the Kern County mountains due to low clouds and mist.

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.