969 FXUS66 KMTR 160114 AFDMTR Area Forecast Discussion National Weather Service San Francisco Bay Area 614 PM PDT Sat Oct 15 2022 .SYNOPSIS...A robust marine layer continues to bring patchy fog, low clouds, and coastal drizzle each night and morning, while the interior remains dry. Some cooling this weekend brings interior temperatures close to or below normal, but temperatures warm up again next week. && .DISCUSSION...as of 12:15 PM PDT Saturday... Today and Tonight: An amplified upper ridge will extend from the eastern subtropical Pacific through the Pacific Northwest States and southwest Canada. Meanwhile a closed upper low will move onshore over northern Baja. At the surface, weak upper troughing will exist just offshore from CA and this will induce a more southerly wind component across the area for today. Otherwise it's pretty much status quo from a forecast perspective with a robust marine layer remaining in place. Therefore look for clouds to gradually retreat towards the coast by this afternoon with plenty of interior sunshine. Despite the sun, inland areas should cool off a bit with the onshore flow with readings only in the 70s and 80s. Coastal and near-coastal areas will remain cool with highs mostly in the 60s. Clouds and some fog should return for many areas tonight with patchy drizzle along the coast. Lows will drop into the upper 40s (inland valleys) and 50s (elsewhere). Sunday through Friday: The previously mentioned upper low will devolve into an open-wave trough and eject towards the Southern Plains early in the period. Mid to upper ridging should then build across much of the western CONUS, with another trough/closed low near SoCal by late week. This will place our area between the influence of the large-scale ridge and the upper trough to our south, with increasing influence from the trough towards week's end. While no sensible impacts to our weather are anticipated, temperatures will be modulated by these features with a warming trend for inland locations by mid week under the influence of the upper ridge. Thereafter expect some cooling on Thursday into Friday as its influence wanes. Onshore flow should prevail through the period keeping coastal locations on the cool side. Next Weekend: A more progressive flow pattern should evolve aloft with upper troughing digging into the Pacific Northwest and Intermountain West. Of less confidence is whether the trough's influence could extend into NorCal. Based on model ensembles and clusters it appears the most likely forecast outcome is for our area to remain dry. However it's noted that a few ensemble members do bring very small rain chances into the Bay Area. And while this is worth watching will defer to the most likely forecast outcome at this time which suggests a continuation of dry conditions for our area. && .AVIATION...As of 6:14 PM Saturday... For the 00Z TAFs. The marine layer depth is 2,500 feet, coastal ceiling bases have increased with the marine layer depth to MVFR. Inland it's VFR. Onshore winds will usher stratus inland again tonight and Sunday morning. Patchy light drizzle tonight and Sunday morning. Surface to lower level cool air advection tonight and Sunday then becomes neutral Sunday afternoon and evening. Stratus /MVFR, possibly IFR/ returning Sunday night and Monday morning. Vicinity of SFO...MVFR ceiling tonight and Sunday morning, west to southwest wind 5 to 10 knots. VFR forecast by 19z Sunday, continuing Sunday afternoon and early evening. KSFO Bridge Approach...Similar to SFO. Monterey Bay...MVFR ceilings and west to northwest winds 5 to 10 knots tonight and Sunday morning. Patchy light drizzle tonight and Sunday morning. VFR from late Sunday morning to afternoon. Stratus returning Sunday night and Monday morning. && .MARINE...as of 05:09 PM PDT Saturday...Light to moderate southwest winds are expected as mixed seas prevail. Winds will be locally breezy through the Golden Gate and across the San Francisco Bay in the afternoon and evening. Patchy fog is possible at times in the Bays during the overnight and morning hours. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...None. $$ PUBLIC FORECAST: SPM AVIATION: Canepa MARINE: SPM Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea