Area Forecast Discussion
Issued by NWS Sacramento, CA
Issued by NWS Sacramento, CA
698 FXUS66 KSTO 152047 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 147 PM PDT Wed Oct 15 2025 For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing. .KEY MESSAGES... - Showers have tapered off as the upper level low exits the region, leaving behind drier weather and well below normal temperatures across the region today - Potential for patchy fog development in the southern Sacramento and northern San Joaquin valleys Thursday morning - Slight warming and drying trend mid to late week as shortwave ridging moves into the area with weak northerly flow - A weak system passing to the north will bring chances for isolated showers, mainly over Lassen Peak and the northern mountains Sunday into Monday - Low confidence in breezy northerly winds early next week behind the passage of this weather system .DISCUSSION... Today...Showers have tapered off and the Winter Storm Warning expired at 5 AM this morning. The upper level low that brought widespread precipitation and mountain snow the past 48 hours will continue to shift off to the east today. Drier weather has returned to NorCal behind the storm and well below normal temperatures are being observed, generally in the 60s in the Valley, 50s in the foothills, and 30s to 50s in the mountains. Current visible satellite imagery shows a swath of broken to overcast cloud over across interior northern California this afternoon. Cloud cover will be decreasing through the day today and tonight. Thursday through Saturday...There is potential for patchy fog development Thursday morning across the southern Sacramento and northern San Joaquin valleys as a result of the recent rain, decreasing clouds and cooler mornings. High resolution guidance indicates a 40-60% chance of visibilities less than a half of a mile in those aforementioned locations for early Thursday morning. Otherwise, weak upper level ridging will develop and move into the region, allowing for weak northerly flow and slightly warmer and drier weather, closer to normal for mid October climatology. Forecast highs in the Valley are in the 70s each day. Sunday...Ensembles and clusters are in decent agreement for an upper trough to move across the Pacific Northwest. Some isolated showers may clip the northern mountains and southern Cascades Sunday and Sunday night. The most recent precipitation forecast from WPC has trended lower and little to no impacts are expected from this. Monday through Tuesday...Behind the passage of this system, there is potential for some breezy northerly winds, mainly along and west of Interstate 5 in the Sacramento Valley and adjacent Coast Range foothills where there is a 35-55% chance of wind gusts greater than 30 mph on Monday. Little to no impacts are expected at this time especially since fuels and fire weather concerns are minimal due to recent rain. We will continue to monitor trends in the pattern and pressure gradient in case the winds trend stronger, as there is still a spread in the ensembles for peak wind gusts. Northerly flow may linger into Tuesday morning as well. /KH .AVIATION... General VFR conditions expected over the area over the next 24 hours. Exceptions to this are local MVFR conditions from lower cloud ceilings possible through 02Z this evening over the northern Sacramento Valley and the potential for patchy fog 12-18z Thursday over the southern Sacramento Valley and northern San Joaquin Valley, bringing IFR/LIFR. Surface winds are expected to be generally light for TAF sites. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$