Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
734 FXUS66 KHNX 020814 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 112 AM PDT Thu Oct 2 2025 .KEY MESSAGES... 1. Chances for precipitation are in store for Thursday into Friday as a low pressure system tracks into the western U.S. In 12 hours ending 5 PM Friday, there is a 30 to 50 percent probability for 0.10 inch for the Sierra Nevada north of Kern County. 2. Cooler air moving in Friday will cause an 80 to 90 percent probability for below freezing temperatures at Tioga Pass. Additionally, there is a 40 to 70 percent probability for an inch or more of snowfall in the higher elevations of the Sierra Nevada from Yosemite to Tulare County through 5 PM Friday. 3. There is a 70 to 80 percent probability for 80 degrees in the San Joaquin Valley and Kern County desert today before falling to 20 to 30 percent on Friday. A warming trend will bring increasing probabilities for the weekend. 4. There is a 60 to 70 percent probability for maximum wind gusts greater than 45 mph for the town of Mojave and State Routes 14 and 58 on Friday. && .DISCUSSION... Temperatures will trend downward a little bit today, though will be most noticeable in our northern portions such as Merced and Mariposa Counties. Noticeable cooling will occur elsewhere by Friday, as temperatures lower to several degrees below average due to a trough of low pressure approaching from the northwest. In the meantime, the first wave of showers due to the approaching trough will arrive in Merced and Mariposa Counties, as well as Yosemite later this morning. Shower activity will shift south by this evening. The trough will move southward and bring at least a slight chance of showers towards Kern County (mainly southern San Joaquin Valley into the mountains) during the overnight hours tomorrow night and early Friday morning. There is also a slight chance for thunderstorms with this system, from this afternoon into Friday. Precipitation will continue over the Sierra Nevada into Friday afternoon. Snow levels in the Sierra will be over 10,000 feet today and lower to 8,000 feet by early Friday morning, including from Yosemite to Tulare County. Snow amounts in these areas continue to have a good chance (40-70%) of reaching an inch and a lower probability (25-50%) for at least two inches. As for rainfall, there is a low to moderate probability (30-50% chance) for at least a tenth of an inch in our northern portions this morning and afternoon and will rise to 65-80 percent in the Sierra Nevada by early Friday. Areas that have a good chance of at least 0.50 inch include the Sierra Nevada and foothills for Fresno County northward. The recent burn scars in these areas will need to be monitored, as brief heavy rainfall is possible, especially if some stronger showers or thunderstorms happen to pass over these areas. Gusty winds are likely (60-70% chance of gusts at least 45 mph) along the Mojave Desert slopes on Friday afternoon and evening. Another relatively cool day is in store for Saturday as cool northwest flow continues in the wake of the trough. For Sunday into next week, temperatures rise back to seasonal levels. Dry conditions prevail until at least early next week, although no significant ridges of high pressure will impact the region for the next several days. Models for the past couple of runs have been projecting another upper-level trough over the Western U.S., as well as a tropical system over the Eastern Pacific, including along the coast of Baja California, for the latter part of next week. We will continue to monitor for potential impacts, especially if we receive tropical moisture. && .AVIATION... MVFR cigs with local IFR possible in SHRA towards MCE and MER and into the Sierra Nevada towards Yosemite NP, spreading southward after 00Z Friday. Otherwise, VFR conditions are expected through 12Z Friday. && .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. && $$ BSO weather.gov/hanford