October 27, 2020 – Critical fire weather conditions will continue today due to gusty winds, low humidity and dry fuels. Lighter winds are expected by mid-week, but very dry conditions will persist.
Discussion
Other than a few high clouds moving down in NE flow, skies are clear across NorCal. Moderately strong offshore flow continues, though surface pressure gradients are a little weaken than 24 hours ago. Critical fire weather conditions persist, though winds are not as gusty as early Monday. Local gusts of 30-40 mph continue over the foothills, and 40-60 mph or higher across the higher elevations of the northern Sierra. RH’s remain very low over most of the area, in the single digits to 20s percent.
Breeziness will continue across the region today. Strong east winds will decrease across the higher elevations of the northern Sierra this afternoon. The Eastern Pacific ridge shifts over NorCal for the second half of the week for dry and unseasonably warm conditions, but lighter winds. Continue practicing fire weather safety.
Extended discussion (Saturday through Tuesday)
EPAC High shifts inland through interior NorCal Saturday and into the Great Basin Sunday. Closed meso low off the CA coast is progged to weaken as it shifts inland across SoCal Monday. Deterministic models differ Tuesday with the GFS/FV3 much more progressive with shifting Pacific frontal system and associated precip into the CWA.
Preferred ECMWF is similar to the ensemble solutions which keep ridging and dry weather in place through Tuesday. Above normal high temperatures expected with upper 70s to lower 80s for the Central Valley and upper 50s to mid 70s for the mountains and foothills.