Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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846 FXUS66 KMTR 171934 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1234 PM PDT Tue Sep 17 2024 ...New SYNOPSIS, SHORT TERM, LONG TERM... .SYNOPSIS... Issued at 1233 PM PDT Tue Sep 17 2024 The next weather system will bright light rain to parts of the region on Wednesday and then taper off from north to south on Thursday. A warming and drying trend is expected by this upcoming weekend and into early next week. && .SHORT TERM... (This evening through Wednesday) Issued at 1233 PM PDT Tue Sep 17 2024 Another upper level low will approach the coast tonight and move across on Wednesday brining generally light rainfall to the region. Coastal drizzle will be possible ahead of the system tonight but transition to light rain showers throughout the day tomorrow. By tomorrow afternoon, the greatest potential for thunderstorms will be across the North Bay with a ~15% (a non-zero chance elsewhere). Rainfall amounts are expected to be light, not amounting to more than 0.10" in most locations expect for locally higher totals in the coastal ranges or where any stronger showers develop. Lastly, winds will not be a concern with this passing system with only 15-25 mph onshore gusts. && .LONG TERM... (Wednesday night through next Monday) Issued at 1233 PM PDT Tue Sep 17 2024 Rain showers will linger into Thursday morning across the Central Coast, tapering off from north to south throughout the afternoon and ending by the evening. Friday looks to remain cool as the mid/upper level trough begins to exit the region but still having an influence. Temperatures over the weekend will trend upward towards seasonal averages. 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... (18Z TAFS) Issued at 1102 AM PDT Tue Sep 17 2024 Stratus is expected to clear out of most airports between 18-20Z. Most sites should clear by 19Z but additional tempos may be needed from 19-20Z for any lingering stratus coverage. VFR conditions are then expected through the afternoon before MVFR CIGs return late this evening/overnight. Stratus is expected to return earlier along the coast with MVFR CIGs to return 00-03Z at MRY and SNS. Winds generally stay light to moderate with southwesterly winds gradually becoming more west to northwesterly during the afternoon/evening throughout the Bay Area. Drizzle chances increase everywhere, except STS and APC, after 12Z with a few sites seeing drizzle chances starting earlier between 05-06Z. Any precipitation that makes it to the surface will be fairly light with totals less than a few hundredths of an inch. Drizzle chances continue through the TAF period but likelihood will decrease heading into late Wednesday. Vicinity of SFO...MVFR becoming VFR by 19-20Z before MVFR CIGs return overnight. Stratus is expected to return between 02-03Z tonight and persist through late tomorrow morning. Drizzle chances generally increase after 12Z through the end of the TAF period. Scattered showers may become more likely after 15-18Z tomorrow but confidence remains too low to include in TAF. West to southwest winds become more moderate during the afternoon/evening before weakening overnight. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Stratus coverage is dissipating at MRY and SNS with patchy scattered clouds showing up on satellite. Ensemble guidance indicates an early return of stratus around 00Z but a few scenarios leaned towards an earlier return closer to 22-23Z. CIGs are generally expected to stay MVFR overnight but there is some potential for CIGs to become IFR overnight. Drizzle chances generally increase after 06Z with the highest probability of drizzle occurring after 12Z. Light, variable winds continue through the remainder of the morning before more moderate west to northwest winds return this afternoon. && .MARINE... (Today through Sunday) Issued at 900 AM PDT Tue Sep 17 2024 Seas continue to abate and light to gentle northerly winds persist through Tuesday. Hazardous seas return Wednesday as a cold front arrives and brings moderate to fresh NW winds and rough seas to the outer coastal waters. Locally stronger winds are expected over the far northern outer waters. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...None. && $$ SHORT TERM...RGass LONG TERM....RGass AVIATION...Kennedy MARINE...Kennedy 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