009 FXUS66 KMTR 181956 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1256 PM PDT Wed Jun 18 2025 ...New SYNOPSIS, SHORT TERM, LONG TERM, FIRE WEATHER... .SYNOPSIS... Issued at 1255 PM PDT Wed Jun 18 2025 Cooling trend begins on Thursday and continues through the weekend. Gusty winds and low daytime humidities lead to elevated fire weather conditions in the interior. Seasonal conditions resume early next week. && .SHORT TERM... (This evening through Thursday) Issued at 1255 PM PDT Wed Jun 18 2025 Satellite imagery shows patchy stratus lingering at the immediate coast, with general clearing through the rest of the afternoon. Overnight, a cold front currently analyzed over the North Coast approaches the region, and while it will not progress further south than the North Bay, the associated upper level low coming into the Pacific Northwest will still provide enough wind aloft to disrupt stratus formation, with any stratus overnight limited to the coastal regions and perhaps parts of the East Bay west of the Berkeley-San Leandro Hills. Speaking of winds, gusty onshore winds will develop this afternoon with peak gusts up to 25 to 30 mph through gaps, passes, and the Salinas Valley, but the winds won't diminish as much as they typically would overnight, especially along the coast and across the higher elevations of the North and East Bay. These gusty winds will lead to increased fire weather threat across the interior (see FIRE WEATHER below). Today sees the last day of warm conditions across the region with high temperatures ranging in the lower 90s to near 100 inland, the 70s and lower 80s along the Bayshore, and the lower to middle 60s along the Pacific coast. Low temperatures on Thursday morning range from the lower to middle 50s in the lower elevations, into the 60s for the higher elevations. Thursday's highs will dip due to the influence of the upper low, with highs reaching the lower 70s to the lower 80s inland and the upper 50s to middle 60s along the coast and Bayshore. Light coastal drizzle is also possible tonight into Thursday morning. && .LONG TERM... (Thursday night through next Tuesday) Issued at 1255 PM PDT Wed Jun 18 2025 Breezy and chilly conditions continue through the weekend, with high temperatures dropping to the 70s inland and the upper 50s to lower 60s along the coast, or around 8 to 15 degrees below the seasonal average, on Friday and Saturday. The upper level low moves northeastward into the Canadian prairie provinces, but some of its energy remains trapped in the western United States, courtesy of a very strong upper level ridge centered over the Ohio River Valley and the Northeastern US. Temperatures will begin to rise on Sunday, and by the middle of next week, it may still feel chilly along the coast, but temperatures in the inland valleys should be much closer to the seasonal averages. CPC guidance suggests that temperatures remain near or slightly below seasonal averages into the first couple days of July, with precipitation totals remaining near the seasonal averages (read: almost nothing) for the same period. && .AVIATION... (18Z TAFS) Issued at 1044 AM PDT Wed Jun 18 2025 VFR anticipated at most TAF sites, except Half Moon Bay and the Monterey Bay Terminals. Otherwise, generally medium confidence in forecast flight category, with low to medium confidence in surface wind forecasts. IFR will linger a little longer at KHAF, before stratus is shunted offshore by daytime heating around 21 UTC. A cold front was analyzed across the Pacific NW this morning per WPC guidance. Some hi-res guidance does suggest that winds become more NW'ly at KSTS this afternoon for a few hours. There's a brief window for MVFR BR at KSTS during the morning hours on Thursday, should winds abate. There's a brief window for MVFR stratus at KOAK during the morning hours. Otherwise, winds will remain elevated with gusts between 20 and 25 knots. Vicinity of SFO...VFR is forecast throughout the TAF period, with medium confidence. There's some guidance that suggests a brief window from 12-15 UTC of MVFR at SFO, but confidence is too low to include at this time. Otherwise, W'ly winds will gust to around 25 knots, largely during the afternoon hours. Sustained winds will remain elevated through the entire TAF period with speeds near 12 knots. SFO Bridge Approach...Similar to SFO with VFR. Monterey Bay Terminals...An eddy continues to swirl across Monterey Bay, but will eventually dissipate through the afternoon. Still, intermittent IFR to borderline LIFR is forecast for a few more hours at KMRY. Confidence in timing is medium. VFR is anticipated through the evening hours with IFR Monterey Bay Terminals...An eddy cigs more probable to return at KMRY around 05Z and linger through the TAF period. Confidence in IFR cigs is low to medium. If onshore flow is weaker than anticipated, VFR may continue through the pre-dawn hours. At KSNS, VFR will dominate the TAF cycle, with a short window of intermittent IFR during the pre-dawn hours (10-14 UTC) on Thursday. && .MARINE... (Today through Monday) Issued at 248 AM PDT Wed Jun 18 2025 Gale Warnings are in effect for the coastal jet areas south of Point Reyes and Point Sur and across the outer coastal waters. Hazardous conditions continue through the forecast period with gusty northwesterly winds and moderate to rough seas continue. Significant wave heights build to 10 to 12 feet across the coastal waters Thursday into the weekend. && .FIRE WEATHER... Issued at 1255 PM PDT Wed Jun 18 2025 A period of elevated fire weather threat begins on Thursday as strong winds gusting at 20 to 35 mph and daytime relative humidities of 15 to 25% develop across the interior, with the biggest threat coming in the interior mountains of the North Bay, the interior East Bay, the eastern Santa Clara Hills, and the Gabilan Range in interior Monterey and San Benito Counties. Fuels have been curing across the interior, especially across the finer fuels of grass and brush, and there's already been several notable grass fires across the interior portions of the region. However, the fact that winds will remain onshore and temperatures will cool will keep fire weather conditions below critical levels. The fire weather threat continues into the weekend, before gusty winds begin to subside heading into the early part of next week. DialH && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-SF Bay N of Bay Bridge. Gale Warning until 9 AM PDT Thursday for Pt Arena to Pt Reyes 0- 10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 9 AM PDT Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt to Pt Pinos 10-60 NM. Gale Warning until 9 AM PDT Thursday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...DialH LONG TERM....DialH AVIATION...Bain MARINE...MM 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