


Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
383 FXUS66 KHNX 271843 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1143 AM PDT Thu Mar 27 2025 && .KEY MESSAGES... 1. Light precipitation is possible in the central Sierra Nevada and along the Sierra Foothills today into tomorrow. There is a 50 to 80 percent chance for greater than one tenth of an inch in these areas by Friday morning. 2. Strong wind gusts will propagate in the Mojave Desert Slopes today through Saturday. A Wind Advisory has been issued for this area due to expected winds 30 to 40 mph with gusts to 60 mph. 3. Above normal temperatures this afternoon will give way to near normal temperatures tomorrow which will last through the next week. 4. There is potential for a system to move through the region next week, however there remains a large amount of uncertainty in associated precipitation totals. && .DISCUSSION... A modest low pressure system currently sits off the coast of the Pacific Northwest region, driving moisture aloft over central California from the west to southwest. Cloudier conditions have been observed this morning as a result, especially along the west wide hills where the deepening marin layer has overcome the coastal range. Skies will gradually clear across the San Joaquin Valley through the morning and early afternoon as surface temperatures begin to warm. However as the system tracks closer to the Pacific coast later this afternoon to evening, another round of increased moisture is anticipated to make its way over central California. While most of the area will only see an increase in cloud cover, there are chances for light precipitation in the northern San Joaquin Valley, central Sierra Nevada, and along the foothills. There is a 40 to 60 percent chance for measurable rainfall in Madera, Merced, and Fresno counties through 5 AM tomorrow morning, mainly on the eastern side of the valley. Moderate low level winds continuing from the west will create a rain shadowing effect for the western valley areas. However, as moisture banks up against the Sierra Nevada due to the regions topography, there is an increased chance for precipitation for the foothill communities. Across the next 24 hours, there is a 50 to 80 percent chance for one tenth of an inch or more including, but not limited to, Oakhurst, El Portal, Camp Nelson, and Alta Sierra. The areas with the greatest probabilities for precipitation are those in and around Yosemite National Park, which has a 60 to 100 percent chance for one tenth of liquid precipitation. Though, with snow levels 7000 to 7500 feet, there is a 30 to 80 percent chance for accumulated snowfall greater than one inch at the higher elevations. Temperatures are anticipated to be a handful of degrees above normal for this time of year due to the flow propagating out to the west to southwest. There is a 50 to 80 percent chance for afternoon temperatures to exceed 75 degrees today in the San Joaquin Valley south of Madera County. A gradual shift to zonal flow is expected beginning tomorrow, which will cause temperatures to decrease back near normal. These temperatures are favorable to maintain into next week as this pattern continues through the forecast period. Due to the near-constant westerly flow through the remainder of the week, stronger wind gusts are expected in the Mojave Desert Slopes and along the crests of the Sierra Nevada. There is a 50 to 80 percent chance for wind gusts to exceed 50 miles per hour in these areas today, with these probabilities shifting to the Mojave Slopes for Friday and Saturday. A Wind Advisory has been issued for the slopes due to expected sustained winds 30 to 40 miles per hour with gusts of 60 miles per hour. In the early to mid period of next week, there are favorable indications that a low pressure system will drop south from the Gulf of Alaska to just off the coast of the Pacific Northwest region. However, from there the models have a fair degree of uncertainty as to the location and intensity of this system moving forward. This uncertainty is best exemplified by the daily 24 hour precipitation probabilities from the National Blend of Models next Tuesday through Friday. For each day in the San Joaquin Valley, the 25th percentile expresses no precipitation occurring. For reference, the 25th percentile indicates a 25 percent chance to remain below the indicated value, with a 75 percent chance to exceed the value. Though on the flip side, the 75th percentile 24 hour precipitation values (specifically for next Thursday) range between half and three quarters of an inch in the San Joaquin Valley. The 75th percentile indicates a 75% chance to remain below these values, with a 25% chance to exceed these values. All this considered, there is still a significant amount of spread in precipitation for next week, which also extends into the foothills and mountain areas of the Sierra Nevada. && .AVIATION... 18Z Update: VFR conditions will prevail across the central California interior until 00Z Friday. MVFR to IFR conditions due to mountain obscuring cloud cover are possible along the Sierra crest and in the Sierra foothills until 12Z. Winds become westerly 15-25kts for much of the San Joaquin Valley after 21Z Thursday. In addition, westerly winds 20-30kts with gusts 40-50 kts expected towards the Mojave Desert slopes in eastern Kern County after 21Z Thursday. && .AIR QUALITY ISSUES... ISSUED: 03/26/2025 14:49 EXPIRES: 03/27/2025 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 low. 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... Wind Advisory until 5 PM PDT Saturday for CAZ338. && $$ public/aviation...SM idss..............EW weather.gov/hanford