textproduct: San Joaquin Valley

KEY MESSAGES

1 Temperatures drop slightly Thursday and Friday before a significant decrease over the weekend.

2. Moisture tracking over the region in the late week period will bring a 10 to 30 percent chance of thunderstorms over the Sierra Nevada on Friday. 5 to 25 percent chance of precipitation Friday in the Valley.

3. Precipitation chances return middle of next week.

DISCUSSION

Here comes the clouds! A nice cloudy morning greeted most of the San Joaquin Valley as the first remnants of the former Tropical Storm Iselle makes its way on shore. As such, our neighbors along the Central Coast are getting some showers. The atmosphere is a bit too dry still for the Central Valley to see anything more than some virga and maybe a sprinkle or two hitting the ground. So, don't get your hopes up for any rain today. What you can get your hopes for is cooler temperatures! There's currently a 15-20% chance of temperatures exceeding 100 degrees in parts of Fresno, Madera and Merced counties. That drops down to a 5-10% chance further south. Tomorrow, the chance for temperatures exceeding 100 degrees is 10-20% in the southern half of the SJV. Until Sunday, temperatures are looking to be more seasonal and even slightly below normal. Normal for this time of year 95-96 degrees.

Friday continues to be the day of most interest around here. Chances of thunderstorms are continuing to increase and now envelop most of the foothills. Elevations above 2,000 feet are having a 10% chance of thunderstorms. These chances increase the higher up in elevation one goes, with the highest peaks of the Sierra Nevada Crest having the best chance of thunderstorms at 32%. There's also a chance of rain in the Central Valley. Currently, there's a 5-15% chance of at least 0.10" rain over the northern portion of the SJV, while from Bakersfield up to Visalia is a 3-10% chance of the same amount.

Going into the weekend, the rain chances will move out as the precipitation tracks further to the north towards Sacramento. To replace that, we'll have those slightly below seasonal temperatures and increased cloud cover. A quiet, but nice weekend.

Looking ahead into next week, models are beginning to hint at another round of precipitation for early to mid week. It's still a bit too early to say what will happen, when it'll happen and where, but the models are at first indicating that another trough will be situated off the Pacific Northwest coast, high pressure will be over the south, and the flow could be from the southwest. Whatever does end up happening, pleasant temperatures should continue on. The CPC has the SJV split in half regarding if we'll be near normal or leaning above normal (33-40% chance).

AVIATION

VFR conditions prevailing for the next 24 hours. Over Merced county, expect hazy and smokey conditions due to a fire north of the city.

AIR QUALITY ISSUES

None. The Air Quality Alert was expired today at 11am per the San Joaquin Valley Air Pollution Control District.

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.