October Weather Retrospective

John McGinley, Peak to Peak. October 2017 was another month that couldn’t decide what it wanted to be. The first week of the month brought abundant snow and cold. The middle of the month was warm and dry with gusty winds. The last week brought a bit more snow and cooler temperatures. Early in the month we had a disturbance to our west that brought a series of cold fronts that ushered in upslope flow, clouds, and snow. This gave way to a large ridge of high pressure that warmed things up and produced the disastrous fire situation in California.

 

Our temperatures were 10 degrees above normal. As the ridge flattened out winds increased with peak gusts reaching 70mph on the 23rd and 24th. Another couple of upslope events in the last week brought a bit more snow on the 26th and 30th.

 

Precipitation: Total for the month was 2.00 inches, 0.77 inches above normal. Most of this fell as snow totaling 18.8 inches or 9 inches above normal. Biggest day of snow was 7.9 inches on the 9th. Good news: this is the third month in row with above normal precipitation.

 

Temperature: Average high for the month was 52F with an average low of 31F. The high was cooler than normal, but the low was warmer than normal (probably owing to the frequent nighttime downslope winds). These two stats made the month slightly cooler than normal, by a fraction of a degree. Eighteen days were freezing or below. The peak temperature was 67F on the 25th; the lowest 14F on the 27th.

 

Winds: We consider a windy day as 40mph or stronger. October was very windy with 13 windy days, double the normal. This put the month in the upper 5% of all windy Octobers…..pretty rare. Four days were over 60mph.

 

Other features: Periods where we have polar air and upslope we usually see a large high pressure system over the Great Basin. This produces strong offshore winds over the West Coast that create hazardous fire conditions. At times winds in California were gusting to 80mph with single digit relative humidities.

 

Outlook for November: With our 11th month we start really feeling winter-like. Average high is 41F with a low of 21F. We typically have 18 inches of snow melting out to 1.12 inches. Winds blow on 11 days with three days over 60mph. Long range prediction models indicate gusty winds early in the month with an arctic blast mid month. After that temperatures will be more mild and conditions general dry and windy.