Freedman: Another Strange Year
Is the weather getting stranger or is it just me?
More people asked themselves this question in 2007, as temperatures edged ever upward. This was, after all, the year when battling global warming turned into a worldwide social and political movement, thereby making odd weather suspicious. The weather of 2007 was unquestionably strange, but it's unclear exactly what this strangeness signified.
Was it a sign of things to come that parts of the Midwest were baked by drought and then submerged in floods in the same year? Was it a portent of the climate of the future that an EF-2 tornado, a category with winds between 111 and 135 miles per hour, touched down in Brooklyn, stunning street savvy New Yorkers? Or was it just the weather being the weather, bipolar and off its meds?
In reviewing the weather of this past year I'm reminded of a moment in one of the "Airplane!" films when the hapless pilot is looking over the instrument panel of his doomed aircraft when a warning light appears, blinking simply: "Strange." This warning light is now illuminated regarding the daily weather, but it's unclear if the light was on the entire time, like the "check engine" light in my mother's car.
There are increasing signs that while the weather has always been odd, it's been getting stranger in an important direction that matches global climate trends.
The challenge lies in teasing out the fingerprints of global climate change from daily weather extremes. While climate scientists have stated with increasing certainty that extreme weather and climate events are likely to occur with greater frequency and severity due to greenhouse gas emissions, a single weather or climate event cannot be attributed to global warming. Yet at least in the category of temperature extremes, it's curious that much of the U.S. experienced far more record heat than record cold in 2007.
In a unique piece of enterprise climate reporting, Seth Borenstein of the Associated Press found that 263 all-time high temperature records were recorded at U.S. weather stations in 2007, with much of the records set in August, when more than 8,000 new heat records were set or tied for specific August dates. This contrasted with only 14 all-time low temperatures that were set or tied all year long, as of early December.
In metro Washington, the weather during 2007 hewed closely to the worldwide warming trends, with one addition: it was also reliably boring and uncommonly benign.
Washington escaped much of the destructive weather of 2007, and instead was dominated by two sedating forces: dryness and mildness. Not too bad considering what happened in Greensburg, Kan., when an EF-5 tornado literally vacuumed the town off the face of the earth, and in southern California, where devastating wildfires tore through valuable real estate.
Last winter in D.C., the lack of snow and record warmth dominated conversation. Let's face it: last winter was cause for despair among DC snow lovers, who cling to hopes that this year will be different. The lackluster winter was followed by a scorchingly hot and dry summer (translation: more boring weather). With two exceptions, a list of the Top 5 weather events in Washington last year is enough to put me to sleep. There was a 34-day dry spell, heat waves in August and October, and two winter weather events that made the cut. There was no blizzard, no hurricane, not even a noteworthy severe thunderstorm outbreak.
Let's review the wintry events first, and leave the more sleepy events for last.
The most significant but also silliest winter storm of 2007 was the Valentine's Day ice storm that brought loudly falling, accumulating sleet to the region. We, along with most other forecasters, had difficulty pinning down the exact precipitation type with that one due to subtle but important variations in computer model projections of the atmospheric temperature profile. "This storm is not a snowmaker for Washington, D.C.," we stated before the storm, noting the potential for a wintry mix.
More snow fell than was forecast in a storm on February 25th, when 3 to 6 inches (with more to the north and west of D.C.) fell across the area. That one was, unfortunately, a bit of a surprise.
Then there was the warm and boring: an August heat wave when the temperature hit 102, and the warmest October on record by far that was capped off by three straight 90 degree days. A record dry streak of 34 days ended on October 19, but not before 34 days of boring.
Thus, even though 2007 signaled the continuation of worrisome climate trends, it wasn't all bad for the D.C. area. But it was strange.
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