Chilly air to hang out in the West through early November
After a brief cooldown, much of central and eastern North America will likely turn mild again as we head into early November, as a strong upper-level ridge builds over northern Ontario and Quebec.
This week and at least half of next week look to become very stormy from Northern California to southwestern British Columbia with rounds of heavy rainfall and mountain snow, which may lead to areas of flooding and debris flows. These storms will also bring significant wind to the coast and mountains. Burn scar areas will be especially prone to debris flows and flash flooding. This pattern may effectively put an end to the fire season for most regions from far Northern California on northward and bring drought relief.
Fall foliage is way behind schedule in the East, with many areas still without a frost or freeze. Down here in Pennsylvania, I would say we are about 10-12 days behind schedule with flowers still blooming and the grass needing to be cut every week. In my 30+ years of living here, I can easily say that this will be the latest for peak color and most likely will be my latest freeze that I can remember.