PROSSER, Wash. – Abnormal heat, raging wildfires and blackened skies choked with smoke. This frightening setting might sound like it belongs in a Hitchcock film, but it was all too real in the Pacific Northwest in September. Washington’s forests burned for much of the month as a rain-free streak exceeded three months across parts of the state.
“The solar dimming caused by smoke-filled skies created interesting weather anomalies last month,” said AgWeatherNet meteorologist Nic Loyd. “Areas like Wenatchee experienced several cloud-free days when well over half of the potential solar radiation was blocked by smoke. As a result, day-time temperatures were as much as 15 to 20 degrees cooler than less smoky parts of eastern Washington.”
A Web based, publicly available system, AgWeatherNet provides access to near real-time weather data and value-added products from Washington State University’s statewide weather network, along with decision aids for agricultural producers and other users.
A tinder-dry environment set the stage for trouble when a dry lightning storm in central Washington on the night of Sept. 8 sparked the inferno. Sunny and hot conditions facilitated high fire danger, while a stagnant atmosphere allowed smoke and pollutants to reach periodically unhealthy levels.
For much of the month, hazy sunshine and glowing red sunsets highlighted the skies. Smoke was often the only thing that obscured the sun east of the Cascade Mountains during the mostly cloudless month.
Thousands of firefighters were called on to help battle the numerous blazes along the east slopes of the Cascades. By mid-September, around 100 fires were burning in Yakima and Kittitas counties. Significant fires were active for most of the month in the mountains adjacent to Wenatchee, Ellensburg and Yakima, with many tens of thousands of acres burned.
The welcome passage of a weak weather system on Sept. 25 brought brief improvement of the poor air quality in eastern Washington. However, the need for a soaking rain across the active fire regions was unrealized.
Although September’s weather was not generally detrimental for agricultural interests, the prolonged lack of rainfall could soon negatively impact some Washington crops.
“The unusually dry weather is becoming a concern for eastern Washington dryland wheat growers,” said AgWeatherNet director Gerrit Hoogenboom. “Luckily, central Washington tree fruit growers can depend on irrigation water. The dry weather also has facilitated the harvest of apples, pears, grapes, hops and other crops.”
With the exception of a windy, cool and autumn-like storm on Sept. 10, high pressure dominated the weather for much of September. The lone significant weather system of the month featured the state’s only significant rainfall in recent memory, as parts of western Washington recorded up to 0.4 inches. Widespread highs in the 60s were recorded, along with wind gusts up to 40 mph and light snowfall in the high Cascades.
Pullman experienced several cold mornings, including Sept. 12 when a chilly low of 25 degrees sent people scrambling for jackets.
Otherwise, hot, dry and uneventful weather was the rule for the month. Particularly warm weather on Sept. 7 sent temperatures soaring above 90 degrees from the coast to Vancouver and Olympia, while 90s were recorded in parts of eastern Washington on Sept. 8. Overall, September temperatures were unseasonably warm in eastern Washington during the day, despite being tempered by periods of thick smoke. The AgWeatherNet station at WSU Prosser recorded an average monthly high temperature 1.6 degrees above normal.
For more information on Washington’s September weather, as well as other weather information, please see the Summer Weather Review on the AgWeatherNet website, http://www.weather.wsu.edu, located under the News link.
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Contacts:
Nic Loyd, WSU AgWeatherNet meteorologist, 509-786-9357, nicholas.loyd@wsu.edu
Brian Clark, WSU CAHNRS Marketing, News and Educational Communications, 509-335-6967, bcclark@wsu.edu
Nic Loyd, WSU AgWeatherNet meteorologist, 509-786-9357, nicholas.loyd@wsu.edu
Brian Clark, WSU CAHNRS Marketing, News and Educational Communications, 509-335-6967, bcclark@wsu.edu