PULLMAN, Wash. – Just as each of the Three Stooges has his unique personality, so did each month of winter in Washington. December was Curley, with lovable yet unpredictable behavior ranging from mild temperatures to stormy conditions and heavy snowfall.
Stern Moe arrived in January, with a cold, stagnant air mass that dominated the state for much of the month. Following such distinctive and dichotomous periods, Larry was an uneventful, non-descript February finish.
The net result was a warmer than normal winter, thanks to a mild December and February. The absence of arctic air intrusions contributed significantly to the above average seasonal readings.
“Prosser’s coldest temperature this winter was only 16 degrees,” said Nic Loyd, meteorologist for AgWeatherNet at Washington State University. “There have only been two other winters since 1992 that remained above 16 degrees for the entire season.”
A Web-based, publicly available system, AgWeatherNet provides access to near real-time weather data and value-added products from WSU’s statewide weather network, along with decision aids for agricultural producers and other users.
Curley and Moe: A warm, white December and stoic January
Temperatures climbed to 60 degrees in early December throughout parts of south central Washington, and a blizzard arrived on Dec. 17 with strong winds and heavy snow for the Cascades. Several days later, cool and active weather allowed parts of Washington to enjoy a white Christmas.
Still, the mild start to December made it central Washington’s warmest since 1999.
There were a couple periods of active and mild weather during January. Generally, however, it was a cold and stagnant month in the lowlands, due to a strong ridge of high pressure.
The middle of January was dry and calm, as strong inversions brought low clouds and poor air quality to the state. On the afternoon of Jan. 15, some areas of the mountains and foothills were as warm as 70 degrees, while central Washington cities were trapped in the 20s. January maximum temperatures at Prosser were the coldest since 2004.
Larry: February turned upside down
Temperatures are normally warmer during February in response to increasing solar radiation, but cooler air showed up later in the month to help counteract that this year. Some areas, including Pullman, were several degrees cooler the final week of February in comparison to the beginning weeks.
The main exception occurred in northern areas like Omak, where inversions and lingering snow cover caused cold weather earlier in the month.
The most significant weather event of the month was the strong Feb. 22 storm in western Washington that featured heavy rain, strong winds and up to two feet of mountain snow.
Overall, however, February was a dry and mild month. Areas east of the Cascades were especially warm during the day, but nights were somewhat cool thanks to clearer skies. Western Washington was relatively cool during the day, due to abundant cloud cover, and mild at night.
The first half of February consisted of weak weather systems brushing western Washington, while eastern Washington was mainly sunny. During the second half of the month, rain returned to western Washington and snow periodically fell in the mountains.
“Benign and favorable weather conditions allowed pruning, field clearing and other preparations for the growing season to begin in earnest during February,” AgWeatherNet director Gerrit Hoogenboom said. “The calm weather has left most fields and orchards in a strong starting position for 2013, and hopefully that trend will continue.”