textproduct: San Joaquin Valley

KEY MESSAGES

1. Low pressure trough begins to lift today, leading to a slight increase in temperatures.

2. A ridge will build Wednesday, leading to temperatures well above seasonal normals through at least this weekend.

3. Moderate Heat Risk is expected across our forecast area from Thursday into next week.

DISCUSSION

The couple days of cooler weather will unfortunately be short lived as a ridge builds into the southwest beginning on Wednesday and seemingly parks itself in place for the next week or more. This will cause temperatures to rise 10 to 15 degrees above normal, keeping the summer-like heat even after the astronomical beginning of fall that occurred on the Autumnal Equinox a week ago. By Thursday, Moderate Heat Heat will enter the Valley before becoming widespread by Friday and maintaining a similar area through mid next week. Temperatures are expected to peak on Saturday, and the southern Valley has a 50-70% chance to see the return of triple digits in the afternoon. These chances decrease the next day, but only to 40-60%.

These conditions are not likely to let up in the week after next either, as the Climate Prediction Center continues to have our CWA under the 80-90% likely above normal temperatures for both the 6 to 10 day and 8 to 14 day outlooks, though the area of that percentile is reduced in the latter outlook, suggesting a potential weakening of the ridge. But even with that, temperatures may continue to be above normal, just not to the current expected extreme.

AVIATION

VFR conditions will prevail 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.