Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
532 FXUS66 KHNX 092239 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 239 PM PST Sat Nov 9 2024 && .KEY MESSAGES... 1. There is a 75 to 95 percent chance of a high temperature of at least 70 degrees through Monday in the San Joaquin Valley before lowering less than 10 percent on Tuesday. The probabilities climb back up to 25 to 55 percent for Wednesday and Thursday. 2. There is a 40 to 70 percent chance of a tenth of an inch of rain or more between Monday afternoon and Tuesday morning for most of the San Joaquin Valley north of Kern County. Chances are 20 to 40 percent for Kern County. 3. There is a 30 to 45 percent probability of 2 inches of snow or more above 7000 feet between Monday afternoon and Tuesday morning near Yosemite with lower probabilities and snowfall amounts further south in the Sierra Nevada. && .DISCUSSION... A weak upper level ridge is currently centered over the western United States, continuing seasonable conditions across central California today that will prevail through the remainder of the weekend. Maximum afternoon temperatures in the San Joaquin Valley are projected to be in the low 70s today and Sunday, around two to five degrees above normal for this time of year. A weak upper level trough in the eastern Pacific will slowly approach the region this evening, but is expected to break down on approach. Some moisture associated with the trough will entrain across California, resulting in slightly increased cloud cover overnight, though no precipitation is expected. The lack of moisture associated with this trough will struggle to raise the relative humidity in the San Joaquin Valley, with minimum values during the day remaining around 15 to 25 percent and as such, there is still an elevated risk for fire danger in the area. A pattern change will come Monday into Tuesday as a stronger upper level low pressure system tracks into the Pacific Northwest region. A deep trough is anticipated to extend south along the west coast from the center of the trough, entering central California late Monday into Tuesday morning. Conditions during the day on Monday ahead of the trough will be mainly representative of the weekend, with temperatures a few degrees above normal for this time of year. However, there will be increased moisture associated with this early week trough due to stronger southwesterly winds aloft. The National Blend of Models expresses a 40 to 70 percent chance for 24 hour rainfall totals to exceed one tenth of an inch for the San Joaquin Valley north of Kern County; Kern County has a 20 to 40 percent chance of these values. Snow levels have trended down from the previous few days to 6,500 to 7,000 feet on the front side of the trough to below 5,000 feet behind the central axis. The combination of additional moisture and these lowered snow levels will bring a moderate to high chance for snowfall to the Sierra Nevada. The following are probabilities from the Weather Prediction Center for various snowfall total thresholds associated with this system. >=0.1" >=1" >=2" >=4" Tioga Pass 89% 71% 42% 3% Tuolumne Meadows 86% 64% 29% 0% Yosemite Valley 63% 30% 8% 0% Badger Pass 76% 44% 9% 0% Wawona 44% 7% 0% 0% Glacier Point 63% 26% 6% 0% Crane Flat 33% 0% 0% 0% Huntington Lake 64% 25% 3% 0% Wishon Lake 47% 15% 1% 0% Lodgepole 37% 5% 0% 0% Along with the probabilities for precipitation, the trough will bring increased winds to central California, particularly the Sierra Nevada crests Monday evening, followed by the Kern County Desert and Mojave Slopes on the backside of the system Tuesday. Areas including Tioga Pass and Mammoth Lakes have a 60 to 70 percent chance to experience wind gusts greater than 40 miles per hour. Meanwhile, there are similar probabilities for wind gusts to exceed 50 miles per hour in and around the town of Mojave Tuesday. These elevated wind gusts Tuesday will be due to winds on the backside of the trough directed from the northwest. These winds will also bring a cooldown to the region, with the San Joaquin Valley struggling to get out of the 60s; NBM ensemble guidance shows a 70 to 90 percent chance for temperatures to remain below 67 degrees Tuesday afternoon. In the midweek period, a weak ridge of high pressure will warm temperatures back near normal with a 70 to 90 percent chance to exceed 67 degrees Wednesday and Thursday. Otherwise, conditions will be similar to those experienced over this weekend. Cluster analysis from the Weather Prediction Center continues to point towards another trough propagating into central California from the Gulf of Alaska. In contrast to the system earlier in the week, this late week system appears favorable to deepen further southward, driving additional moisture and colder air into our region. && .AVIATION... 18Z Update VFR conditions will prevail across the Central CA Interior for the next 24 hours. && .AIR QUALITY ISSUES... ISSUED: 11/08/2024 16:00 EXPIRES: 11/09/2024 23:59 On Saturday November 9 2024, Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno, Kern, Kings, Madera, and Tulare Counties. Burning Discouraged in Merced County, and Kern (Greater Frazier Park Area) and Sequoia National Park and Forest. && .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... None. && $$ public/aviation...SM weather.gov/hanford