“Last month was again abnormally mild, and there was minimal frost during the final three weeks of March,” said Washington State University AgWeatherNet director Gerrit Hoogenboom. “Crop development is generally two to three weeks ahead of schedule, and south central Washington cherries and apples were already at or near bloom by month’s end.”
A Web-based, publicly available system, AgWeatherNet (http://weather.wsu.edu/awn.php) provides access to near real-time weather data and value-added products from WSU’s statewide weather network. It offers decision aids for agricultural producers and other users. It is based at the WSU Irrigated Agriculture Research and Extension Center in Prosser.
80 degrees in March
March temperatures at Prosser were nearly five degrees warmer than normal, including more than six degrees above normal during the day. Following a relatively cool and dry beginning, March trended somewhat wetter and much warmer for the remainder of the month.
March 27 was a remarkable day where several stations in south central Washington set all-time March high temperature records. Wapato reached an impressive 80 degrees while Pullman topped out at 72 degrees.
Otherworldly high pressure
The cause of the anomalous weather over the last year or so has been the remarkably persistent large-scale atmospheric circulation pattern.
“The background state has featured a warm, semi-permanent ridge of high pressure near Washington,” said AgWeatherNet meteorologist Nic Loyd. “Unfortunately, it has been behaving like the thing from another world. Even when the ridge finally seems to disappear, it quickly returns as strong as ever within a few days.”
A month of extremes
Highlights of March include various temperature and rainfall extremes. The low temperature at Pullman was 19 degrees on March 4, but the low temperature at Mount Vernon was a balmy 53 degrees on March 11. On March 15, Long Beach registered nearly 1.8 inches of rain.
Washington’s long-range outlook continues to favor warm and perhaps dry conditions for the remainder of 2015 and into early 2016. El Niño may also be poised to strengthen in the coming months. If a stronger El Niño is in place next winter, the odds of a low snowpack year increase substantially.