521 FXUS66 KHNX 102227 AFDHNX Area Forecast Discussion National Weather Service San Joaquin Valley - Hanford CA 327 PM PDT Wed Oct 10 2018 .SYNOPSIS...With the exception of isolated showers over the high Sierra Thursday, dry weather will prevail over the central California interior for the next 7 days. Temperatures will average cooler than normal through Thursday. Friday through next Wednesday will bring much warmer afternoons. && .DISCUSSION...Temperatures are trending 3 to 9 degrees lower across much of the central California interior this afternoon compared to 24 hours ago. The cooler change can be attributed to a weak upper level trough that is currently settling southward into the Great Basin. Although this system is limited on moisture, it is producing a good deal of cloudiness over the higher elevations of the Sierra from Kings Canyon National Park northward this afternoon. Additional energy that feeds into this upper level trough during the next 24 hours will produce some instability showers over the Sierra which could bring up to a tenth of an inch of rain in some locations and local snow accumulations of an inch or less above 8,000 feet between tonight and Thursday night. This will probably be the last time precipitation falls in the high Sierra for awhile. In fact, it looks as through dry weather will be the rule for much of the next 7 days over the CWA as a blocking upper air pattern sets up along the West coast. The aforementioned block will consist of a strong upper level ridge of high pressure that is currently centered off the Pacific Northwest coast and a closed Low that is going to develop off the southern California coast during the next 24 hours. As this pattern evolves, it will produce a modest offshore flow over the Golden State by the end of this week. These offshore flow patterns ultimately warm up the atmosphere across much of central California, especially along the coast and in the interior valleys. After another cooler than normal day Thursday, Friday will become noticeably warmer as a result. The offshore flow will likely become accentuated over the northern half of the state this weekend as a strong surface high pressure system settles into the northern Rockies. This offshore flow will also bring a drier air mass into the district by Sunday, especially over the mountains and desert. While the high pressure ridge off the Pacific Northwest coast becomes the primary player in our weather pattern by this weekend, we will be keeping our eyes on the closed low that develops off the southern California coast during the next 36 hours. The models forecast this low to tap into tropical moisture from Sergio and direct it toward Arizona and New Mexico from late Thursday into Saturday. It's possible that some of this higher level moisture could become wrapped around the closed low off the southern California coast and be thrown into Kern county Friday into Saturday. If so, it may be in the form of opaque cirrus in the Kern county mountains and desert and probably nothing more than that. Nonetheless, it's something we'll be monitoring. Otherwise, once our weather warms up Friday, it will remain warmer than normal for many days thereafter (at least through next Wednesday). The nights, on the other hand, will be relatively cool/chilly through the period. && .AVIATION... Local MVFR/IFR ceilings are possible over the higher elevations of the Sierra into Thursday evening. Otherwise, VFR conditions will prevail over the Central CA Interior for at least the next 24 hours. && .AIR QUALITY ISSUES... 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.php for additional information an/or to provide feedback. && .HNX Watches/Warnings/Advisories... NONE. && $$ public...Durfee avn/fw...MV synopsis...Durfee weather.gov/hanford