From PG&E’S weather awareness page
Thursday, Sept. 24, 2020
PG&E Meteorology is closely tracking the potential for dry northerly winds to develop Saturday evening and continue into Monday morning across Northern CA. The event start is still about 60 hours away from this time (Sept. 24, 8 am) and as we get closer, some details regarding strength, timing and location of the event may change if models evolve. The northerly winds will coincide with very hot temperatures and the National Weather Service has issued a Fire Weather Watch for portions of Northern CA valid from Saturday through Monday. The Northern Operations Predictive Services has also forecast ”High Risk” for strong and dry offshore winds combined with dry surface fuels. Please refer to weather.gov, https://gacc.nifc.gov/oncc/, or https://gacc.nifc.gov/oscc/ for the latest updates from federal forecast agencies. At this time PG&E Geographic Zones 2 and 5 are in PSPS Watch Saturday night through Monday morning.
Details: A passing cold front brought rain to northern Humboldt last night, but precipitation has tapered off and fair and dry weather is expected for all locations today. Temperatures will remain close to or slightly above normal today and tomorrow before a strong ridge of high pressure builds over California and results in a pronounced warming trend this weekend. Widespread triple digit heat is possible Sunday and Monday, including near the coast and in coastal valleys. Breezy north or northeast winds are also expected at times across the northern interior starting Saturday afternoon/evening and continuing at times through Monday morning. Strongest winds are expected during the overnight and morning hours Saturday and Sunday in the northern Sierra foothills where gusts in excess of 45 mph are possible. Slightly cooler conditions are possible near the coast early next week, but very hot and dry conditions will continue through at least the first half of next week. Fire danger remains seasonably high as live fuel moisture values are at critical levels in the lower and middle elevations and dead fuel moisture values are at seasonal minimums. The latest National Interagency Fire Center wildland fire potential outlook favors above normal large wildland fire potential for most of Northern CA for September and October followed by normal large fire potential for November and December.
Please note: This forecast is published daily by an operational meteorologist from PG&E’s Meteorology and Analytics team. This forecast has been customized for PG&E utility operations and should not be used for any other purpose or by any other entity. This forecast only provides a broad overview for a potential Public Safety Power Shutoff (PSPS) event in the next 7 days as determined from an analysis of forecasted weather, the potential for wind-related damage, and fuel moisture content in dead and live vegetation. It is not a fire danger forecast. The forecast is broken down by broad PG&E Geographic Zones numbered 1 – 9; however, PSPS decisions are made at more granular levels; thus, only a portion of a zone may experience a PSPS event. While a PSPS event may not be expected for an area, due to the interconnectivity of the grid any location within PG&E territory may be subject to PSPS event.