


Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA
Issued by NWS San Francisco Bay Area, CA
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417 FXUS66 KMTR 191009 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 309 AM PDT Thu Jun 19 2025 ...New SYNOPSIS, SHORT TERM, LONG TERM, MARINE, FIRE WEATHER... .SYNOPSIS... Issued at 305 AM PDT Thu Jun 19 2025 Cooling trend starts today and will continue into the weekend. Elevated fire weather concerns across much of our interior today, especially elevated grassy areas where gusty winds will combine with dry conditions and increasing fuels. King tide coastal flooding possible Sunday into the beginning of next week. && .SHORT TERM... (Today and tonight) Issued at 305 AM PDT Thu Jun 19 2025 The first of several shortwave troughs will begin to transect our area later this afternoon into tonight. Temperatures will be right around normal today with breezy winds this morning out ahead of the first weak cold front that pushes through our area this afternoon. Winds increase behind the surface becoming gusty later today and tonight front especially at higher elevations inland and near the surface along the coast. Wind gusts up to 50 MPH are possible above 2000ft across the East Bay hills during the overnight into early Friday morning. A wind advisory is not expected attm. && .LONG TERM... (Friday through Wednesday) Issued at 305 AM PDT Thu Jun 19 2025 Robust onshore flow Friday will result in the marine layer expanding and penetrating farther inland as an upper low pushes inland across the Pacific Northwest and a tightening pressure gradient continues the gusty winds along the coast and elevated interior locations through late Saturday into early Sunday. Fire weather concerns abate for Friday into the weekend despite the gusty winds with improved RH recovery. Still watching the upper level pattern for Sunday into the beginning of next week, for the potential of a stalled upper low/trough possibly leading to weak offshore flow and increased fire weather concerns. && .AVIATION... (06Z TAFS) Issued at 941 PM PDT Wed Jun 18 2025 850 mb cold air and dry air advection arriving on northwest winds are helping to keep VFR going area-wide except it`s 5 miles /MVFR/ in haze/mist at KHAF. The ACV-SFO and UKI-STS pressure gradients are 8.2 mb and 1.7 mb respectively while the onshore pressure gradient is 3.5 mb. Nocturnal radiative cooling to space and lower level cold air advection may combine to produce redevelopment of coastal stratus later tonight to the predawn hours Thursday, though by how much areal extent of development is a very challenging forecast. It`s moderate to high confidence the Bay Area terminals stay VFR tonight with exception of IFR in stratus and mist/fog developing at KHAF tonight and Thursday morning and it may be slow for KHAF to mix out Thursday. Otherwise for the north Central Coast it`s a moderate to high confidence VFR forecast for early to mid evening then it`s a low to moderate confidence IFR forecast mid to late evening and overnight. VFR inland Thursday, along the immediate coastline patchy stratus /IFR-MVFR/ may linger. Vicinity of SFO...VFR. Gusty west wind to 30 knots gradually subsiding tonight. Gusty west wind near 30 knots Thursday and Thursday evening. Stratus /MVFR/ returning Thursday evening and night. SFO Bridge Approach...Similar to SFO with VFR. Monterey Bay Terminals...VFR conditions extending into late evening, then nocturnal cooling and lower level cold air advection favors redevelopment of stratus /IFR/ tonight and Thursday morning. Tempo IFR forecast 04z-08z at KMRY and KSNS terminals then IFR prevailing tonight/Thursday morning then mixing out to MVFR-VFR by late Thursday morning or early afternoon. Stratus /MVFR-IFR/ returning Thursday evening and night. && .MARINE... (Today through Tuesday) Issued at 305 AM PDT Thu Jun 19 2025 Hazardous conditions and widespread gale force winds over the coastal waters continue into Friday as a dry cold front passage occurs. Winds ease from gale force to near gale to strong late Friday into Saturday which will persist into early next week. Winds will be strongest across the outer waters and for the inner coastal waters north of Point Reyes and south of Point Sur where coastal jets are expected to develop. Significant wave heights build to 10 to 12 feet across the coastal waters Thursday into the weekend before abating early next week. && .FIRE WEATHER... Issued at 305 AM PDT Thu Jun 19 2025 Elevated fire weather concerns today with strong winds gusting at 25 to 40 mph and daytime relative humidities of 15 to 25% developing 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 into the weekend. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 1 PM this afternoon to 3 AM PDT Friday for Mry Bay-SF Bay N of Bay Bridge. Gale Warning until 9 AM PDT Friday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory until 9 AM PDT this morning for Pt Reyes to Pigeon Pt 0-10 nm. Gale Warning from 9 AM this morning to 9 AM PDT Friday for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 9 AM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm. Gale Warning until 3 AM PDT Friday for Pigeon Pt to Pt Pinos 10- 60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. && $$ SHORT TERM...JM LONG TERM....JM AVIATION...Canepa MARINE...Kennedy 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