You didn't imagine anything if it felt a little chilly outside Friday.
Friday was the coldest November 9 ever recorded at Sea-Tac Airport, according to the National Weather Service. Seattle’s high of 43 was the coldest since records started in 1945. The low at Sea-Tac Friday morning was 35.
Temperatures are expected to drop back into the 30s again Friday night and into Saturday morning.
The last time Seattle had a low of 32 or below was back on February 26, the NWS tweeted.
The chill in the air is due to a few things happening in our weather pattern.
First, we haven't had cloud insulation to keep us warm. The clouds usually act as a blanket and help trap air that was heated by the sunshine. So without those clouds, all the daytime heat escapes into the air above.
Next, the winds were light and mainly out of the north and northeast. That wind direction dries out the air a bit, which brings us to the Greenhouse Effect. The Greenhouse Effect is a natural way the earth warms its surface by trapping some of the sunshine during the day, kind of like a greenhouse traps warm air under the glass. When it comes to our cold nights, what's important to know is that the most effective greenhouse gas is water vapor, or relative humidity. Water vapor helps hold heat so it doesn't get quite as cold as it does with less water vapor. Because we dried out a bit overnight with the north and northeast wind flow, that meant one chilly morning.
