textproduct: San Joaquin Valley

UPDATE

Updated 00Z Aviation Section.

KEY MESSAGES

1. Temperatures will remain above average through the weekend.

2. Gusty winds will develop late Wednesday through early Thursday morning along the Mojave Desert slopes and at times through the weekend.

3. Practice cold water safety, as waterways will be running cold and fast over the next several days.

4. Chances for precipitation and cooler temperatures return early next week.

DISCUSSION

Another warmer than average day is in store today, although low temperatures were slightly lower than yesterday's. The chances of highs reaching at least 85 degrees for today are at 70-80 percent in the SJ Valley, while for the desert the probability reaching or exceeding 90 degrees is also at 70-80 percent. Noticeably cooler temperatures arrive on Thursday, as the probability of reaching 80 degrees or warmer is at 50-60 percent for the Valley. This is due to an upper-level low that is currently off the coast of Baja California. As this low moves inland during Wednesday into Thursday morning, winds are projected to increase along the Mojave Desert slopes, with a probability of 75-85 percent reaching at least 40 mph. A warming trend occurs Friday until Sunday, although highs remain in the 80's to near 90 degrees in the warmest locations. Additional opportunities for increased winds in this area will return during the weekend into early next week, and confidence is moderate. Flow aloft becomes more zonal over the weekend as the upper-level ridge flattens.

A trough arrives early next week that will result in a shift to a cooler, more unsettled pattern, with a slight chance of precipitation on Monday in mainly the Sierra Nevada. More widespread chances, including a 30-40 percent chance over the Sierra and 15-25 percent over our SJ Valley and Kern County mountains by Tuesday. The latest CPC outlooks show continued above average temperatures (70-80 percent at 6-10 days and 40-50 percent at 8-14 days), but near average precipitation at 6-10 days with a 33-40 percent chance of above average precipitation at 8-14 days.

AVIATION

VFR conditions are expected for the next 24 hours.

FIRE WEATHER

Warm air temperatures and steady dew point temperatures will continue to result in lower minimum relative humidities, especially for the Mojave Desert, high Sierra, and Coastal Range through this weekend. This will coincide with much lower 100- and 1000-hr dead fuel moistures and higher ERC (Energy Release Component) in these areas. Rapid curing of fine fuels will bring about some risk for isolated grass fires. However, live fuel moisture remains below critical thresholds and significant wildfire potential remains at little or no risk.

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.