The Cool and Damp Weather of May-June 2010: Winners and Losers
Many sunlight-deprived residents of Washington State are complaining about the recent weather. Those that live on the west side of the Cascade Mountains are accustomed to cloudy and wet winters, and a slow warming as the days get longer during the spring. There is a basis to the adage that summer starts here after the 4th of July. That being said, the spring of 2010 has been highly unusual in its virtually uninterrupted series of cloudy, cool and often wet days. This short article points out some of the benefits, as well as the disadvantages, of our run of relatively foul weather.
Let’s start with the downsides. An obvious one is lack of heat for gardeners and farmers. It’s one thing for westsiders to wonder how much longer their spindly tomato plants will continue to sulk, but it is a serious matter for farms east of the Cascades. According to a recent issue of the Weekly Weather and Crop Bulletin (WWCB), field crops are up to four weeks behind schedule, and cut hay has been damaged by the relatively frequent rains. These rains have also compromised the quality of sweet cherries harvested recently. Strawberries have been prone to mold and their harvest has been delayed.
Less appreciated are the impacts our weather has on the marine ecosystem along the coast of the Pacific Northwest. Generally, during the spring, the winds switch from blowing predominantly from the southwest to out of the northwest. This wind shift heralds the upwelling of cold, nutrient-rich water from depth along the coast, which fertilizes the plankton forming the base of the food web. The unusual weather of the last 2-3 months has included less frequent/weaker than normal northwesterly winds from northern California to Vancouver Island resulting in suppressed upwelling. Delays in the usual seasonal shift in the winds can have serious repercussions from plankton to fish to top predators such as seabirds and marine mammals as it reduces the amount of adequate food that each species can find. There is evidence that some upwelling has occurred recently, so hopefully, conditions here are in the process of turning around.
There is also some good news – and it is not restricted to owners of tanning salons. All that extra water falling out of the sky has led to some real benefits. The enhanced water supply has meant more hydropower generation, which may be particularly relevant in light of the low snowpack of last winter. According to the National Resource Consevation Service (NRCS), water storage for the state is now at or above average. The additional water eases concerns about meeting agricultural and other needs during the upcoming summer. Cooler stream temperatures and high streamflow in May and June is beneficial for juvenile salmon that leave the streams for the ocean, and has helped the adult salmon of species that are already returning to the streams. The wet weather has also benefited pastures and some other crops. State forests presently have fuel moisture levels that are considerably higher than the same time last year, which tends to delay the onset of the fire season. Finally, unless the summer is unusually hot and dry (which is possible, as hard as that might be to believe) the groundwater discharge to streams should be reasonably healthy, with positive implications for the freshwater habitat of salmon and other fish.
In closing, the residents of Washington State are encouraged to embrace their inner slug. Cool and cloudy seems a reasonable alternative to the sweltering heat being experienced in the desert southwest and other regions of the country. Summer is approaching and there should be plenty of fine weather. Enjoy it while you can! La Nina is developing (see below)…but that is a topic for a later newsletter.