Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
846 FXUS66 KHNX 022114 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 114 PM PST Tue Dec 2 2025 && .KEY MESSAGES... 1. Fog development will continue overnight into Wednesday morning across the San Joaquin Valley. 2. A dry disturbance will introduce increasing winds across the deserts and mountain peaks from Wednesday into Thursday; cold morning lows also anticipated for the high Sierra. && .DISCUSSION... Low stratus cloud cover continues over the central valley this afternoon after lifting from the valley surface. Stagnant and subsiding air aloft will cause rising moisture from the valley to settle in the low levels of the atmosphere, gradually improving visibilities at the surface. However, a knock-on effect will need to occur to remove this stratus cloud deck where warmer surface temperatures cause the clouds to erode, which will in turn lead to more of the surface receiving sunlight, causing warmer temperatures, and so on.Clearer skies yesterday came about with help from stronger low level winds mixing out the saturated air, which will likely need to happen again today, given that the persistence of the stratus deck has extended further than model guidance indicated. Without clearing, we can expect this cloud deck to continue into tomorrow morning. This being said, a shortwave upper level trough is expected to make its way through the Great Basin this afternoon through early Thursday morning, with the vorticity maximum of the trough tracking due north/south over central California. The vortmax and increased winds at the center of the troughs axis may allow for enough low level mixing to occur over the valley areas to cause clearer conditions to prevail into Wednesday, however these elements will need to extend into the lower levels in order to do so. More definitive impacts from the incoming trough will be seen in the higher elevations of the region. Cold, dry northerly air will be entrained into this area, causing dangerously cold conditions Wednesday and Thursday mornings. Minimum temperatures above 9000 feet are expected to approach 10 degrees Fahrenheit, but with the added effect of the wind, apparent temperatures are projected to fall into the negatives. Due to this, a Cold Weather Advisory has been issued for the Sierra Nevada above 9000 feet. Starting in the late week, more benign conditions will return due to the influence of a high pressure ridge over the eastern Pacific. The high will direct more significant weather further north and east of central California, while prolonging the stagnant conditions currently observed over the region. && .AVIATION... Conditions are expected to improve into MVFR/VFR after 20Z and continue through at least 06Z-09Z Wednesday. IFR/LIFR conditions will return for the valley areas afterwards, especially for KFAT, KVIS, KPTV, and KHJO which have a 50 to 60 percent chance for LIFR visibility or less through at least 15Z-18Z Wednesday. && .AIR QUALITY ISSUES... On Tuesday December 2 2025, Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno, Kern, Kings, Madera, Merced, and Tulare Counties. Burning Discouraged in Kern (Greater Frazier Park Area) and Sequoia National Park and Forest. && .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... Cold Weather Advisory from 7 PM this evening to 9 AM PST Thursday for CAZ323-326>328-330-331. && $$ public/aviation...SM weather.gov/hanford