textproduct: San Joaquin Valley

UPDATE

KEY MESSAGES

1. Dry conditions and brief warm up are expected through the weekend before temperatures dip back below normal early next week.

2. Another trough moving in out of the Pacific Northwest may bring precipitation to the region once again by next Friday.

DISCUSSION

The system that finally broke the summer-long dry spell will continue to move east through the overnight hours, followed by a small ridge coming out of the Pacific. This will lead to a short warm-up and drier conditions over the next few days, though temperatures are expected to be at or a couple of degrees above normal (normal being in the upper 70's for the lower elevations at this time of year). And while the Valley will see minRHs in the 40-50% range, both the Sierra Nevada and Mojave Desert will see minRHs fall into the teens and lower 20's by Tuesday and continuing into Wednesday.

This will begin to change by Thursday next week in the lead up to a potential second system in the form of a broad trough moving through the west coast by next Friday and into the Halloween weekend. But this potential precipitation is very uncertain due to the fact that the day of occurrence is 8 days away, and, as of current model runs, precipitation is only seen in the 75th percentile and above, meaning the chance for the region receiving any rainfall is 25%. So we will need further model runs to see if the confidence in the event will become weaker or stronger, but this will of course be monitored everyday for any changes.

AVIATION

Areas of MVFR to IFR due to lowered visibility until 16Z. Otherwise, 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.