FXUS66 KMTR 170517 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1017 PM PDT Thu Apr 16 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 112 PM PDT Thu Apr 16 2026 - Periods of gusty offshore winds, especially at higher elevations, continue through early Friday morning - Seasonably warm temperatures expected Friday and Saturday - Cooler temperatures and beneficial rain Sunday into early next week && .SHORT TERM... Issued at 112 PM PDT Thu Apr 16 2026 (This evening through Friday) Gusty offshore winds continue across the higher terrain through late Friday morning as a deep upper level trough pushes into the Northern Rockies. The strongest gusts are expected across the Vaca Range and the Mayacamas Range in Sonoma and Napa Counties respectfully. Winds shifted offshore (north to northeast) early this morning with Mt. St. Helena reporting a peak gust of 58 mph at 9:30AM this morning. Outside of the highest peaks (including Mt. St. Helena), gusts are expected to peak between 35 to 45 mph with locally stronger gusts across the highest peaks/ridgelines. Winds ease slightly this afternoon/evening before restrengthening tonight into Friday morning. By late Friday morning, winds will diminish across the higher elevations as the deep upper level trough progresses eastward and ridging builds over the West Coast. Very dry daytime conditions continue across the interior today and tomorrow due to the moderate offshore winds. Overnight humidity recoveries will be good along the coast but poor across the interior higher terrain (where gusty winds continue throughout the night). Fire concerns remain minimal thanks to the recent wetting rains and the upcoming wetting rains next week. Seasonal high temperatures in the 60s to low 70s continue across the interior while highs in the 50s to 60s prevail along the coast. Friday morning continues to look chilly as clear skies overnight will lead to increased radiational cooling. Much of the region will see low temperatures in the 40s on Friday while portions of the eastern Santa Clara Hills and the interior Central Coast drop into the 30s. Residents in the vicinity of Parkfield and Bradley (Monterey County) will see temperatures drop into the low 30s. By the afternoon, chilly temperatures will be a distant memory with highs rising back into the low to mid 70s across the interior and 50s to 60s along the coast. This slight warming trend will continue into Saturday as upper level ridging rebuilds over the West Coast. && .LONG TERM... Issued at 112 PM PDT Thu Apr 16 2026 (Friday night through next Wednesday) Seasonably warm temperatures continue into Saturday as upper level ridging builds. Interior highs will peak in the mid to upper 70s with coastal areas staying in the 60s. Temperatures start to cool Sunday as the ridge progresses east with seasonal temperatures in the 60s to low 70s expected across most of the region. Seasonably warm temperatures continue for one more day across the interior Central Coast where highs linger in the mid to upper 70s. As the ridge exits, a deep upper level trough will push into the West Coast with an associated weak surface low and cold front. Model guidance is still split as to when the trough will arrive. The GFS favors a slower arrival (more so Monday-Tuesday) whereas the ECMWF favors a slightly faster arrival late Sunday into Monday. In terms of ensemble cluster guidance, three of the five clusters support a stronger low that lingers offshore of California Sunday through Tuesday. The other two clusters support a more progressive low that moves inland faster. If the cut-off low lingers offshore, rather than progressing inland, that may allow the storm to overperform slightly and see higher amounts of rain across the region. Thunderstorms are also possible Monday and Tuesday afternoons with around a 10-20% chance of thunderstorms on Tuesday. Guidance shows a few hundred joules of MUCAPE with decent lift and moisture from the low. Models are showing early potential for a NCFR to develop on Tuesday which will be interesting to see how it evolves as this system gets closer in time. Rainfall totals from this event are still beneficial with around 1.5-2.5" expected across the North Bay, 1-2" across the coastal mountain ranges, and 0.5-1.0" across the lower elevations. Locally gusty onshore winds are expected Monday into Tuesday along the coast and across the higher elevations but winds are forecast to stay below Wind Advisory criteria. Temperatures drop into the 60s across the region starting Monday and remain there through midweek while morning lows remain in the 40s to low 50s. && .AVIATION... (06Z TAFS) Issued at 1009 PM PDT Thu Apr 16 2026 VFR is expected to prevail through the forecast period. Enhanced offshore flow aloft is producing LLWS out of the northeast for the North Bay terminals and farther south into KOAK. Vicinity of SFO...VFR is expected to prevail through the forecast period. Expect northeast LLWS aloft through the overnight into Friday morning, especially at KOAK. SFO Bridge Approach...Similar as SFO. Monterey Bay Terminals...Expect VFR through the TAF period with offshore flow overnight, returning back to onshore by late morning. && .MARINE... (Tonight through next Wednesday) Issued at 1009 PM PDT Thu Apr 16 2026 Gale force winds have eased over our northern outer waters this evening. Strong winds will persist through Friday morning with hazardous conditions persisting across our outer waters and continued choppy conditions for inner waters and bays. Winds will ease further by Friday afternoon into Saturday with seas gradually subsiding. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. && $$ SHORT TERM...Kennedy LONG TERM....Kennedy AVIATION...JM MARINE...JM Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, X, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea