FXUS66 KMTR 190008 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 508 PM PDT Wed Sep 18 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 131 PM PDT Wed Sep 18 2024 Isolated to scattered rain showers continue into this evening, tapering off from north to south gradually through Thursday afternoon. A warming trend is on tap for by this upcoming weekend and into early next week with temperatures rebounding to near seasonal averages. && .SHORT TERM... (This evening through Thursday) Issued at 131 PM PDT Wed Sep 18 2024 An upper level low remains off of the North Bay coast at this hour and will continue to drop southward throughout the day before moving onshore over the Central Coast tonight/tomorrow. As such, much of the rainfall from this system will remain light and some locations may not see any rainfall at all! There remains a slight chance of thunderstorms across the North Bay this afternoon before the thunderstorm threat focuses on the southern portion of the Central Coast on Thursday. The threat generally remains less than 15% however, so confidence of thunderstorm development remains low. Wrap around moisture from the system as it pushes inland will result in the continued rain chances (and low end thunderstorm chances) into tomorrow over the Central Coast but the North Bay and Greater San Francisco Bay Area are expected to be dry beyond late this evening. Any thunderstorms that to develop will have the potential to produce isolated, brief downpours. Temperatures both today and tomorrow will be 5-15 degrees below seasonal averages. && .LONG TERM... (Thursday night through next Tuesday) Issued at 131 PM PDT Wed Sep 18 2024 Friday afternoon will still be below normal across the region as the upper level trough begins to push further inland. The warm-up doesn't begin until Saturday with near to slightly below normal temperatures. Sunday and into early next week is when temperatures are expected to be slightly above average as high pressure from the eastern Pacific begins to build inland. The marine layer also looks to return as a result with night and morning low clouds likely into next week. Low clouds will the retreat to the coast by the afternoon each day throughout the week. && .AVIATION... (00Z TAFS) Issued at 508 PM PDT Wed Sep 18 2024 It's VFR with high based clouds and widely scattered showers. Patchy low clouds and fog /MVFR-LIFR/ developing tonight and Thursday morning, improving to VFR by late Thursday morning. Vicinity of SFO...VFR-MVFR. Onshore wind near 12 knots decreasing this evening and becoming light northeast Thursday morning, then onshore near 12 knots Thursday afternoon and early evening. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR-MVFR, a few passing showers are possible tonight and Thursday. Onshore winds 8 to 15 knots, decreasing this evening and becoming light and variable tonight and Thursday morning. Onshore winds 10 to 15 knots Thursday afternoon and early evening. && .MARINE... (Tonight through next Monday) Issued at 458 PM PDT Wed Sep 18 2024 Northwesterly breezes will be gentle to moderate, increasing to become moderate to fresh over the outer waters by Thursday. Seas will be moderate, building to become rough in the outer waters by Thursday. There's up to a 15% chance for thunderstorms through tomorrow which could produce lightning, locally heavy rainfall, locally gusty winds, and small hail. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM Thursday to 3 PM PDT Friday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...RGass LONG TERM....RGass AVIATION...Canepa MARINE...Sarment 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