Snow Cover and Low Temperatures

As mentioned in a previous blog post, nighttime low temperatures can vary widely during a long, winter night depending on cloud cover, winds, and snow cover. And these changes can be quite dramatic over a short distance. Clear skies with light winds and fresh snow cover can lead to very chilly low temperatures, while the opposite will lead to significantly warmer conditions.

So here is a capture of the last visible picture from yesterday which gave us a clue about how extensive the snow cover was. Generally speaking, the only widespread snow cover was found over the Palouse and Camas Prairie.

And here is a high resolution visible image this morning, showing the snow over southeast Washington and the Camas Prairie.

Meanwhile, the cloud cover was largely confined to the locations southeast of the snow cover as well as over portions of northeast and north central Washington.

So what were the resultant low temperatures this morning?

The coldest reading was indeed at Pullman-Moscow airport with a low of -4F.  Winchester (north of Grangeville) registered a -1F reading.  Meanwhile, despite the snow cover in Bonners Ferry, they only reached a low of +9F, due to the aforementioned clouds.

Here's a zoomed image showing the temperature reports from the Pullman/Lewiston area.

So what does that mean for tonight's temperatures?  The image below shows our forecast for tonight.  

In general, temperatures should be colder tonight than last night.  There will be less cloud cover tonight, and the winds will be weaker.

The cold weather will continue through the weekend and into next week.  In fact, a surge of even colder air will arrive on Friday, which could result in dangerous wind chills in some areas.