Fine summer weather ends abruptly

Did summer here in Central Oregon seem somewhat abbreviated to you?

If so, you're not alone. Weather data collected at the Sisters Ranger District clearly shows that this was indeed the case. June was cool and wet until the last week of the month, when summer finally decided to make its appearance.

Once on the scene, however, it turned out be of high quality.

The warm, sunny and dry weather we are so accustomed to here held strong through July, August and almost all of September. Temperatures in the 80s and 90s were the norm, while triple-digit heat occurred only twice. No measurable precipitation was recorded during the entire period.

Unlike some years when fine summer weather often lingers well into October, the 2009 version suddenly dropped out of sight as September drew to a close.

Temperatures during the first few days of October were significantly below normal, as frigid air from extreme northwestern Canada was drawn southward by a high amplitude trough that developed along the coast of British Columbia.

While the coldest air stayed east of our area, more directly impacting northeastern Washington, Idaho and Montana, enough of it filtered into Central Oregon to keep temperatures dropping through the first third of the month.

During the early morning of October 4, the first snowfall of the season made its debut in Central Oregon. Bend was hardest hit with anywhere from 5 to 7 inches of the white stuff. La Pine to the south got about two inches, while Sisters to the north generally saw an inch or less. And it would only get colder.

On October 10, 12 and 13, Sisters recorded a low temperature of 17 degrees F. Redmond set a record low temperature for the date of 15 degrees F on the October 11. Snow returned to the region on February 13, when one to two inches of snow fell in and around the Sisters area.

So, is this unusually cold early autumn weather a preview of things to come, or just a brief spell of freakish atmospheric conditions that say nothing about the upcoming winter? To learn more about this intriguing question, read "Forecasters look ahead to winter" linked below.