If you feel like you have your head in the clouds, in a sense, you do.
After all, it’s April in the Inland Northwest.
Clouds tend to be a common occurrence this time of year. And though many different cloud types exist, two often emerge in the depths of spring.
Cumulus are those puffy, whimsical clouds that float among blue skies. They’re the ones children draw with crayons and which are featured in the opening sequence of the TV show “The Simpsons.” Cumulus clouds add quiet character to otherwise sunny days but can turn dramatic when they grow into big thunderheads.
Which brings us to this cloud type: Cumulonimbus. Shaped like huge cauliflowers, they often form when cumulus clouds bubble up to create a dense powerhouse cloud capable of producing heavy rain, hail, thunder and lightning. In parts of the tropics, cumulonimbus clouds occur almost daily. In our region, they make sporadic appearances in spring and summertime.
What is it about spring that causes these two cloud types to form? The changing weather.
As the sun becomes warmer, the Earth’s surface heats up as the upper air level remains cold. In a process called convection, the warm, less dense air becomes buoyant and rises, turning into clouds in the cooler layer of upper air.
We’ve also seen plenty of nimbostratus clouds this month. The ones most likely to rain on your parade, they are gray, dreary and appear to cover the entire sky. They also produce persistent, light to moderate rainfall.
So yes, cloudy days and rain dominated the first half of this month. From April 1-15, 10 days were cloudy, and five were partly cloudy. We’ve also had plenty of drizzle, a thunder storm and on four days, it just plain rained. All courtesy of cumulus, cumulonimbus and nimbostratus.
Because every cloud has a silver lining, sunshine is on the way. Drier and clearer conditions are expected as we approach the summer season.
Nic Loyd is a meteorologist with Washington State University’s AgWeatherNet. Linda Weiford is a WSU news writer and weather geek. Contact: firstname.lastname@example.org or email@example.com.