Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
040 FXUS66 KHNX 092131 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 231 PM PDT Sun Mar 9 2025 && .KEY MESSAGES... 1. A storm system looks to skate to the south of the region on Monday and Tuesday with the probability of measurable precipitation ranging from 10 to 25 percent for the Kern Mountains and the Mojave Slopes. 2. An Atmospheric River Event is favorable Wednesday into Thursday with significant precipitation for all of Interior Central California. Strong wind gusts are likely to accompany this system along the Sierra crests and in the Kern County Desert. 3. A Winter Storm Watch has been issued for the Sierra Nevada above 3000 feet from 11 PM Tuesday through 11 PM on Thursday due to possibly heavy snow through that time period. Total snow accumulations of 1 to 3 feet above 4000 feet and up to 4 feet at the highest elevations of the Sierra Nevada can be expected. && .DISCUSSION... Another clear day across the region this morning, with highs likely to reach into the 70`s later this afternoon. This is due to the ridge aloft promoting drier conditions and a slight warm-up. Current satellite shows a line of clouds approaching the west coast, with a trough behind it. This trough is expected to become a cut-off low pressure system by tomorrow that will just pass to the south of our CWA, with a 20 to 40 percent chance for measurable precipitation along the Kern County Mountains as a result of the system pushing in moisture from the southeast of the Kern Mountains. The San Joaquin Valley is not likely to see any rain as chances are less than 10 percent, though there may be some sprinkles on the Sierra Nevada as the moisture is lifted up and condensed on those peaks. The main event for this week is likely to begin late Tuesday evening, as a strong low pressure system is anticipated to impact the region through early Friday morning. Significant precipitation can be expected with this system, as it has been showing in the ensemble models for several days, and remaining fairly consistent, adding confidence to this forecast. As a result, a Winter Storm Watch has been issued for the Sierra Nevada mountains above 3000 feet from 11 PM Tuesday evening through 11 PM Thursday evening. Current expected snow accumulations is expected to be 1 to 3 feet above 4000 feet and up to 4 feet at the highest elevations of the mountains. Between 3000 and 4000 feet, snow accumulation can be expected to be 6 to 12 inches. Snow levels are expected to fall fairly quickly as this system moves through, beginning around 6000 feet on Tuesday and falling to around 3000 feet by Wednesday night when the bulk of the snow will have fallen on the Sierras. After the snow level drop, the Kern County Mountains may see 6 to 12 inches of snow above 3000 feet, with a Winter Storm Watch likely to be issued by tomorrow. The mountain passes of Tejon Pass and Tehachapi Pass may also be impacted by this system, as current probabilities for 2 inches of snow are 70 percent and 44 percent respectively. This would make driving on the I-5 and Highway 58 through those passes hazardous. This system is also likely to produce very strong winds along the Sierra Crest and Kern County Mountains and high desert. Wind gusts along the crest during the passage of the system could reach up to 55 mph as the snow is falling, and the Mojave Slopes and Desert may see winds in excess of 70+ mph, with the city of Mojave currently seeing a 62 percent chance for wind gusts of 64 mph or higher and a 45 percent chance for gusts of 74 mph or higher on Thursday. The Kern Desert proper is also likely to see strong winds, with current chances at California City of 55 mph being 61 percent on Thursday, as well. Along with the wind and snow, there may be moderate rain for the San Joaquin Valley and moderate to heavy rainfall for the Sierra Foothills with this system. For the Valley, a 24 hour rainfall total of 0.75 inches on Thursday currently has a 25 to 55 percent chance of occurring, with Fresno near the top of that range, mainly due to the placement of the strongest part of the trough hitting the Fresno and Tulare Counties almost head on. The foothills can expect heavy rain at times, with probabilities of 2 inches of rain over a 24 hour period on Thursday being 30 to 60 percent. The WPC has also put the foothills under a Marginal (5%) Risk for excessive rainfall on Thursday. After this upcoming system clears out, another weak system may glance off Central and Southern California and another trough may bring more precipitation to the region by next week, with the CPC 6 to 10 day outlook showing a 50 to 60 percent chance for above normal precipitation for the middle of the month. && .AVIATION... 00Z Monday Update: VFR conditions will prevail throughout the central California interior for the next 24 hours. && .AIR QUALITY ISSUES... ISSUED: 03/08/2025 13:20 EXPIRES: 03/09/2025 23:59 None. && .CERTAINTY... The level of certainty for days 1 and 2 is medium. 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... Winter Storm Watch from Tuesday evening through Thursday evening for CAZ318-320-322>331. && $$ Public/Aviation/Fire Weather....EW DSS/PIO.........................BSO weather.gov/hanford