FXUS66 KHNX 302037 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 137 PM PDT Wed Oct 30 2024 .KEY MESSAGES... 1. Afternoon highs continue to trend below normal across Central California through the weekend. 2. There is a 50-60 percent probability of a one inche of snow or more above 6,500 feet in Yosemite NP on Thursday. 3. There is a 50 to 70 percent probability of at least quarter of an inch of rain in the San Joaquin Valley from Friday evening through Saturday afternoon. There is a 20 to 40 percent probability of a tenth of an inch of rain from Saturday afternoon to Sunday afternoon. 4. There is a 50-70 percent probability of 4 inches or more of snow above 6,500 feet on Saturday. && .DISCUSSION... Afternoon highs continue to trend several degrees below normal across the San Joaquin Valley, and this trend is not forecast to change. This is due to low pressure systems that have continued to usher in cooler air across Central California. So far, these systems have not had much moisture associated with them, and the shortwave disturbance that will impact Central California is no different. NBM guidance shows a 40%-50% chance of light precip tomorrow morning in the San Joaquin Valley, with light snow in the Sierra Nevada. This precip event will conclude by late Thursday, with a broader system on its heels. By Friday, a trough of low pressure/closed low will dig southward. This trough will bring renewed chances of precip across the San Joaquin Valley, seasonally cold temperatures, and snowfall in the Sierra Nevada this weekend. Precip chances on Friday begin to increase in the overnight hours. Snow levels are projected to begin at around 7,000 feet and then fall to 6,000 to 6,500 feet on Saturday. As the trough digs southward Saturday morning, the this is when the chances of rain/snow will be at their greatest. Currently, probabilistic guidance is showing the snow continue through Saturday afternoon, with there being a 70% chance of a least 4 inches of snow at Tioga Pass by 5 PM Saturday. Rainfall chances continue in the San Joaquin Valley at the same time, with about one quarter to one half of an inch of rain through Saturday night. As the cold front associated with this disturbance continues to shift southward late Saturday night, mountain snow and valley rain will gradually come to an end. By Sunday, the precip will mostly have ended, leaving cooler afternoon highs in the wake of this disturbance. Model guidance shows afternoon highs running several degrees below normal Saturday and Sunday. Currently, we are seeing about a 70-90% probability for afternoon highs in the San Joaquin Valley to remain below 70 degrees this weekend. Early next week, blended model guidance indicates a slow but steady trend back up to the low 70s across the valley. This modest warming trend can be associated with a ridge of high pressure building in the Eastern Pacific. Central California looks to be on the eastern periphery of this ridge, so the warming trend, at least as of this writing, will be limited. && .AVIATION... VFR conditions will prevail throughout the Central CA interior for the next 24 hours. && .AIR QUALITY ISSUES... ISSUED: 10/29/2024 15:36 EXPIRES: 10/30/2024 23:59 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. && $$ ab weather.gov/hanford