National Weather Service - Discussion


Area Forecast Discussion

National Weather Service - San Joaquin Valley / Hanford, CA
Issued: Thursday, January 20 2022 - 2:34 AM PST

SYNOPSIS... High pressure will continue until Friday and allow continued chances of morning Tule Fog. Gusty northeast winds will be possible in the Sierra Nevada by Friday afternoon until Saturday morning as an inside slider passes through the Great Basin. Dry weather is expected to continue into the foreseeable future.

DISCUSSION... Benign weather will continue throughout Central California due to a prevailing ridge of high pressure until Friday, while high temperatures will rise to several degrees above average again today. The exception is patchy dense fog will develop in the San Joaquin Valley once again this morning. While the ridge is expected to weaken by Friday, valley fog could also develop in the morning hours.

During Friday afternoon and evening, an upper-level low pressure system will pass over the Great Basin as an inside-slider trough and produce northeast flow over the mountain areas. This feature will allow a slight lowering in afternoon high temperatures; however, the primary impact due to this system will likely be windy conditions over portions of the Sierra Nevada. Per blended guidance, probabilities of gusty winds exceeding 50 mph have risen considerably for locations in the higher elevations of the Sierra Nevada, mainly towards Yosemite and south to Fresno County. Some isolated gusts to 70 mph are also conceivable. So, confidence is increasing in terms of this development. Later Friday evening into Saturday, the upper-level low will pass south over the Colorado River Valley and eventually over Baja California. Gusty northeast winds will likely spread southward into Kern County as this system progresses. Gusts around 50 to 55 mph with isolated stronger gusts are also possible in these areas. It appears we could have a brief break from valley fog, if enough atmospheric mixing occurs with this system.

For Sunday into early next week, high pressure returns, and no precipitation is projected. The possibility of morning/nighttime dense fog returns to the Central Valley, although daytime highs will remain above average.

AVIATION... MVFR with local IFR to LIFR visibility in fog across the San Joaquin Valley through 18z Thursday and possibly redeveloping after 06Z Friday. Otherwise, VFR conditions will prevail across the Central CA interior during the next 24 hours.

AIR QUALITY ISSUES... On Thursday January 20 2022... Unhealthy for sensitive groups in Fresno and Kern Counties. Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Kings... Madera... Merced and Tulare Counties. No Burning For All in Fresno and Kern Counties. Further information is available at


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 for additional information an/or to provide feedback.

HNX WATCHES/WARNINGS/ADVISORIES... High Wind Watch from Friday morning through late Friday night for CAZ323-326.