June 15, 2020 – Another weather system will bring increasing clouds and wind to the region today along with a slight chance of showers across the far northern mountains of California. Warmer temperatures, lower humidity and breezy north winds will bring elevated fire weather concerns during mid-week. Hot weather settles in for the end of the week.
Clear to partly cloudy skies cover the region early this morning. Current temperatures are considerably milder compared to 24 hours ago and generally range from the lower 40s in the mountain valleys to the 60s to lower 70s across the Central Valley and foothill thermal belts.
Clouds and gusty southwest winds will increase across the region today as upper trough approaches NorCal and pushes a mostly dry cold front southward into far northern California. Moisture is pretty limited, but a few light showers will be possible across the higher peaks of the northern Coast Range and across the extreme southern Cascade Range.
Wind gusts in the 20-30 mph range will be possible today across the southern Sacramento Valley and northern San Joaquin Valley with locally higher gusts in the mountains. Temperatures will be several degrees cooler today compared to Sunday across the northern half of the forecast area, while readings to the south will be similar to yesterday.
Ensembles are in good agreement indicating the trough will move inland across the PacNW on Tuesday before lifting out to the northeast across the northern Rockies into the Canadian prairie provinces during mid-week as ridging from the eastern Pacific builds into NorCal.
Temperatures will cool a bit across the region on Tuesday with the trough moving through, and winds will begin to shift to the north with some local breezes developing across the Sacramento Valley.
Significant warming returns Wednesday and Thursday with valley highs forecast to return to the 90s. Gusty north winds will also develop through the Central Valley on Wednesday as surface gradients tighten behind the departing trough (MFR-SAC gradient forecast to be around 10-12 mbs early Wednesday). Combined with lowering humidity, the breezes will result in elevated fire weather concerns for the lower elevations. North wind will continue Thursday, but won’t be as strong as Wednesday.
Extended Discussion (Friday through Monday)
Strong upper ridging persists over interior NorCal Friday through Monday resulting in continued hot and dry weather. High temperatures in the Central Valley expected to range from around 95 to 103, hottest in the Northern Sacramento Valley. Mountains and foothills will see highs from the 70s to 90s. Locally gusty north to east wind continues Friday into Saturday.