November lacked its usual share of precipitation due to a ridge of high pressure early in the month and a drier upper flow later in the month said Jesse Ellis, Fire Weather Forecaster in the monthly weather synopsis.
“No temperature or precipitation records were broken this month,” Ellis said. “The mean monthly temperature was a half degree warmer than average.”
Ellis said a ridge of high pressure stalled near the BC coast to help keep a dry northwesterly flow in place over the region for the first third of November.
This resulted in the first significant snowfall of the year arriving on November 12th, which started off as a few minor sprinkles of rain in the morning.
This precipitation soon turned to snow due to a combination of a dry airmass in the valley and increasing precipitation rates.
“Snow was fairly wet and short-lived as afternoon temperatures rose to around 3C.
Ellis said the majority of November’s precipitation, 85 percent, fell as rain between November 15th and 19th, due to a series of Pacific frontal systems passed over the West Kootenay.
He said temperatures during this stretch peaked between 5C and 7C each day with overnight lows generally above 3C.
Later in November, a drier upper flow — predominantly out of the northwest —regained control for the majority of the rest of the month.
“A modified Arctic airmass pushed into the area from the north and east towards the end of the month, partially helped out by a deep low pressure centre south of the US border,” Ellis said.
“This pattern brought the greatest winds (gusting above 40km/hr) and the lowest temperature of the month (-8.4 degrees) on November 29th,” he said.
“The record minimum temperature for November is -20.2.”
Ellis said the prevailing dry upper flow resulted in significantly lower than normal precipitation: Total amounts came in at only 32% of normal. Rainfall was 54% below average and snowfall was 11% of normal.
Following Wednesday's Environment Canada Snowfall warning, the forecast is for unsettled weather with some precipitaton, including snow, expected on the horizon.