"2011 Sets U.S. Record for Wet/Dry Extremes, Wettest Year in Philadelphia’s 2-Century Record, Wettest December Day in DC"
Figure 1. Departure of precipitation from average for 2011, as of December 6, 2011. Remarkably, more than half of the country (56%) experienced either a top-ten driest or top-ten wettest year, a new record. Image credit: NOAA/HPC.
– Dr. Jeff Masters in a WunderBlog repost (with added material at the end)
This year is now the wettest year in nearly 200 years of record keeping in Philadelphia, Pennsylvania. A large, wet low pressure system soaked the Northeast U.S. on Wednesday and early Thursday, bringing 2.31 inches of rain to the City of Brotherly Love, bringing this year’s precipitation total in Philly to 62.26 inches. This breaks the old yearly precipitation record of 61.20 inches, set in 1867. In a normal year, Philadelphia receives about 40 inches.
According to wunderground’s weather historian Christopher C. Burt, this is one of the most difficult U.S. city records to break, since rainfall records in Philadelphia go back to 1820. The only other sites with a longer continuous precipitation record in the U.S. are Charleston, SC (1738 -) and New Bedford, MA (1816 -).
20+ inches above average precipitation in Ohio Valley, Northeast
Philadelphia is not alone in setting a wettest year in recorded history mark in 2011. Over a dozen major cities in the Ohio Valley and Northeast have set a new wettest year record, or are close to doing so. Thanks to rains associated with this year’s tremendous tornado outbreaks in April in May, plus exceptionally heavy summer thunderstorm rains, combined with rains from Tropical Storm Lee and Hurricane Irene, portions of at least twelve states have seen rains more than twenty inches above average during 2011.
The fraction of the country covered by extremely wet conditions (top 10% historically) was 32% during the period January through November, ranking as the 2nd highest such coverage in the past 100 years. And if you weren’t washing away in a flood, you were baking in a drought in 2011–portions of sixteen states had precipitation more than twenty inches below average (Figure 1.)
The fraction of the country covered by extremely dry conditions (top 10% historically) was 22% during the period January through November, ranking as the 8th highest in the past 100 years. The combined fraction of the country experiencing either severe drought or extremely wet conditions was 56% averaged over the January – November period–the highest in a century of record keeping [see Figure 2 below].
Climate change science predicts that if the Earth continues to warm as expected, wet areas will tend to get wetter, and dry areas will tend to get drier–so this year’s side-by-side extremes of very wet and very dry conditions should grow increasingly common in the coming decades.
Figure 2. Percentage of the contiguous U.S. either in severe or greater drought (top 10% dryness) or extremely wet (top 10% wetness) during the period January – November, as computed using NOAA’s Climate Extremes Index. Remarkably, more than half of the country (56%) experienced either a top-ten driest or top-ten wettest year, a new record. Image credit: NOAA/NCDC.
Unofficial state yearly precipitation record set in Ohio
The Wilmington, Ohio NWS office announced last week that three stations in Southwest Ohio had unofficially broken the 140-year old state yearly precipitation record. Cheviot, Miamitown, and Fernbank have recorded 73.81″, 71.89″, and 70.85″, respectively so far in 2011, beating the old record of 70.82″ set at Little Mountain in 1870. According to wunderground’s weather historian Christopher C. Burt, the old record should be 72.08” at Mt. Healthy, Ohio in 1880.
Wunderground’s weather historian Christopher C. Burt summarizes the global weather extremes in November in his latest post.
– Jeff Masters
JR: See two posts from last week by Capital Climate:
- Precipitation Records Broken Tennessee to New England
- Wettest December Day in DC History: In fact, Wettest Day During the Entire Cold Season (November-March) in DC History
Related Climate Progress Posts:
- Leading experts explain how human-caused warming exacerbates Texas drought
- NOAA Chief: U.S. Record of a Dozen Billion-Dollar Weather Disasters in One Year Is “a Harbinger of Things to Come”
- The year of living dangerously. Masters on 2010: “The stunning extremes we witnessed gives me concern that our climate is showing the early signs of instability”
- Two seminal Nature papers join growing body of evidence that human emissions fuel extreme weather, flooding that harm humans and the environment
- Climatologist Kevin Trenberth always reminds us:
One of the opening statements, which I’m sure you’ve probably heard is “Well you can’t attribute a single event to climate change.” But there is a systematic influence on all of these weather events now-a-days because of the fact that there is this extra water vapor lurking around in the atmosphere than there used to be say 30 years ago. It’s about a 4% extra amount, it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change. And the prospects are that these kinds of things will only get bigger and worse in the future.