We have been dealing with heavy smoke from the Camp Fire in Butte County, which is a couple hours’ drive north of us. The weather conditions have been such that the smoke has settled and some days it has been like a fog that starts out moderately thick and never totally clears.
What I did not expect was that it would be so cold during this smoky phase. The fire began on 8 November, and the winds that initially made the fire so devastating died down late in the day on the 11th. Since then, we have had six straight mornings with low temperatures at 36F or lower, including three at 32 and two more at 33. This is substantially colder than the norm for this time of year. Usually–at least in the years I have been at this location–we do not get a morning below 32 until some time in December.
The NWS forecast discussion last night mentioned, “The smoke is keeping temperatures below normal blocking heating from the sun during the day and allowing heat to escape at night, unlike cloud cover.”
It is obvious that smoke cover would keep daytime highs down. In fact, we have not had a high temperature higher than 66 for the past six days, and some days have been only 62 or 63. That is near or a little below the norm for mid-November. (Normal low and high temperatures for the month of November around here would be more like 41 and 66.)
I would not have expected smoke to help keep it so cool overnight. Perhaps naively, I would have expected it to act more like cloud cover. Evidently, however, the fire has had the effect of getting our winter-chilling off to an early start. The deciduous trees are presumably dormant enough by now to “receive” chill, so this early cold snap is a good start.
The fire has been one of the worst disasters in the state in some time, and the air quality has resulted in UC Davis being shut down since 12 November and through the upcoming Thanksgiving holiday. Through all the awfulness, these cold mornings have been welcome.