textproduct: San Joaquin Valley

KEY MESSAGES

1. Below normal temperatures continue in the near future with localized rain and snow showers (above 9,000 feet) across the area from tonight through the start of the weekend.

2. More substantial precipitation will move into our area by Saturday evening with a 40-65% chance of at least a half an inch of rainfall from Saturday evening through mid-day Sunday.

3. A Winter Weather Advisory will continue for the higher elevations along the Sierra Nevada mountains with a 15-20% chance of greater than 4 inches of snowfall above 7,000 feet, and a 50-70% chance of greater than 10 inches of snowfall above 9,000 feet.

DISCUSSION

Its All Hallows Eve eve! The spookiness of the season is in full swing. Maybe not tonight, but surely, the ghosts, goblins and ghouls will be out tomorrow. The big ticket item continues to be the rain and snowfall event thatll happen starting tomorrow night and continue through Sunday. The trough and low pressure system is beginning to make its way into California and combine forces, which is why today was overcast with those fluffy cumulus clouds floating lazily throughout the area. Throughout the day tomorrow, expect to see those same clouds.

For those trick-or-treating tomorrow night, this is important! As the time period gets closer, the models continue to stay in good agreement of rainfall. For the 24 hour precipitation chances, by 5pm on Saturday night, those enjoying Halloween events in the Fresno, Madera, and Merced counties can expect a 35-50% chance of 0.1 or greater of rain. In the Foothills, that goes to 80-87% chance of 0.1 or greater of rain. For the remaining counties, there is a 20-35% chance of seeing that 0.1 or more of rain by 5pm. By 11pm, the chance of seeing a quarter inch of rain (0.25) or more is 90% for the Foothills and 40-50% in Fresno, Madera and Merced counties. Kings, Tulare and Kern counties will have a 25-30% chance of 0.25 or more by 11pm. Needless to say, Halloween is going to be bit wet and a bit chilly.

Sunday continues to be the big day for rain and snow. This is due to the trough and low really joining together Saturday into Sunday night. Snow levels will drop to about 7,000 feet, so elevations higher than that will see snow. Currently, theres a 25-50% chance for elevations above 7,000 but below 9,000 feet to see 4 or more of snow by early Sunday morning. Areas above 9,000 feet will have a 60-80% chance to see 8 or more of snow. The highest elevations of the Sierra Nevada have a 50-90% of seeing 12 or more of snowfall through Monday morning (the next 72 hours), hence our Winter Weather Advisory for Sierra Nevada above 7,500 feet. Its happening people!! Time for snowball fights and sledding! Down here in the Valley, itll be rather wet. Theres a 40-80% chance for the SJV to see 0.25 or more of rain by Sunday evening. Even the Mojave desert has a small (15-20%) of seeing that much rain in the same time frame. However, theyre more likely to see 0.1 of rain.

The trough is still expected to move out of California rather quickly. By late Sunday night/early Monday morning, ridging will be setting up and sticking around for a few days. Thisll bring temperatures up to the normal range. And, as it is the season where the fog starts becoming a thought in peoples mind, this is a good time to point out that there is a chance for fog on Monday and Tuesday. That ridge will keep the moisture trapped closer to the surface. We will have better probabilities for fog density as we get closer to the potential event.

AVIATION

A reduction in visibility to around 4-5 statute miles due to haze is possible tomorrow morning at KFAT, KVIS, and KBFL. 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

Winter Weather Advisory from 8 AM Saturday to 7 AM PDT Sunday for CAZ323-326>328-330.