Pacific Gas & Electric has issued a Public Safety Power Shutoff Watch for next Tuesday and Wednesday citing the record-breaking temperatures, low humidity, and high winds resulting in a “above normal significant wildland fire potential for most of Northern California.” The majority of Mendocino County could be impacted as well as neighboring counties including Humboldt, Lake, Sonoma and Trinity.
PG&E said a PSPS Watch means the “Emergency Operations Center (EOC) is activated for a reasonable chance of executing PSPS for public safety in a given geographic zone due to a combination of adverse weather and dry fuel conditions. A PSPS watch is typically only issued within 72 hours before the anticipated start of an event.”
PG&E provided the following analysis to help customers understand the current conditions compelling the utility company to consider a PSPS:
Weather models are starting to come into better agreement regarding the potential offshore wind event late Monday night through Wednesday morning. The start of the event is still more than 2 days away, so details regarding exact strength and location of the event may change moving forward. PG&E Geographic Zones 2, 3, 4, 5, and 8 are now showing PSPS Watch Tuesday and Wednesday with Zone 9 on Wednesday. High pressure will continue to strengthen over Northern California today, bringing a potent heat wave to the territory through the holiday weekend. Away from the coast, hot and dry conditions are expected territory wide, with peak heating occurring on Sunday. Daytime highs across the inland valleys and interior will easily reach triple digits today, with peak temperatures in the 105F – 112F range, with several heat prone locations exceeding 112F. Closer to the coast, expect cooler but above-normal daytime highs in the 70s and 80s. Temperatures will decrease into the start of the week, but remain above-normal as high pressure begins to weaken, and a warm, dry, offshore flow sets up over Northern California. An upper level weather system is expected to drop south into the Great Basin on Monday, and set the stage for offshore winds, primarily across the northern half of the territory. These offshore winds are expected to develop directly on the heels of the weekend heat wave, which exacerbate fuel dryness to near critical values. A return of the sea breeze and more typical late summer weather is forecast for the middle and latter part of next week, with continued above normal temperatures across the interior. The National Weather Service has issued several Fire Weather Watches across the territory, which are likely to be upgraded to Red Flag Warnings as the event gets closer. The latest National Interagency Fire Center wildland fire potential outlook favors above normal significant wildland fire potential for most of Northern CA through October as fuel moisture values are at critical levels in most areas and dead fuel moisture values are near seasonal minimums.