The idiosyncratic summer of 2009 continues, with the Pacific Northwest experiencing an extremely unusual heat wave this week that may be a sign of things to come, courtesy of global climate change. Elsewhere, Texas continues to suffer through one of its worst droughts in memory, and the missing Indian Monsoon finally showed up this week -- in New York.
Meanwhile, after surprising cool temperatures and low humidity for much of June into July, the Washington area has reverted to its more typical warm and humid summer weather with occasional showers and thunderstorms. Considering what's been occurring elsewhere, I'd say the mid-Atlantic has lucked out so far.
Keep reading for more on the strange summer of 2009...
Putting the sizzle in Seattle
The Northwest heat wave, which is now ebbing somewhat, has been remarkable. On Wednesday, Seattle's Sea-Tac Airport recorded an all-time record high temperature of 103 degrees Fahrenheit, breaking a previous record of 100 last reached in 1994. Vancouver, Wash., exceeded its all-time high on Wednesday as well, with a high of 108. The old record was 105. Speaking of 105, Portland, Ore., which like Seattle is not exactly known for its air-conditioned buildings, hit 105 on Wednesday.
According to the National Weather Service (NWS), the heat wave may set duration records as well. If high temperatures in Portland reach 90 or above through Saturday, it will break the all-time record for consecutive days at or above 90, which is eight. Portland is also shooting for its all-time hottest month on record.
While it's impossible to attribute any single weather event to climate change, the unusually intense and long-lasting Northwest heat wave is consistent with climate change studies that show that heat waves are likely to become more endemic features of the American climate. This may be due in part to human emissions of greenhouse gases, because as the overall climate warms, the distribution of extreme temperatures shifts as well, making warm extremes increasingly likely to occur, and cold extremes less common.
The heat wave is causing some residents of the Pacific Northwest to take notice of climate change, with Seattle Times business columnist John Talton writing, "Seattle needs to pause from the "you can tell your grandkids about the great heatwave of '09," and take stock of potential climate-change effects here, including, for the sake of this blog's mission, the economic ones. For this may not be a twice-a-century event any longer."
The heat wave in the Northwest stands in stark contrast to the Northeast and Midwest, where this summer has been barely lukewarm. Through yesterday, New York's Central Park had not yet reached 90 degrees this summer, a feat only accomplished once before. According to the NWS, daily average temperatures have run at or below normal on every day but one in July, and for 54 of the 59 days since June 1. New York has also recorded its second wettest June through July on record, with more than six inches of rain in July, and 1.52 inches on July 29 alone. The city is on track to potentially set a new record for wettest summer ever.
As previously noted, such rainfall is sorely needed in Texas, where an intractable drought has been taking a heavy toll on agriculture and recreation. According to the U.S. Drought Monitor, and the seasonal drought outlook, relief is unlikely through October, although it's possible that a few slow-moving tropical weather systems could change that.