A look at weather extremes and the big-picture climate connections.

The Extreme Weather of 2012 Represented in One Chart

The weather so far this year has been anything but "average." There was that massive heat wave in March that sent temperatures soaring into the upper 80s in the Upper Midwest at a time when it should have been snowing. Tropical Storm Debby dropped more than 2 feet of rain in just a few days on northern Florida. Thousands of record high temperatures were set or tied during a brutal mid-June to early July heat wave, including hundreds of all-time record highs. 

Wildfires burned hundreds of homes in Colorado, while the largest wildfire in New Mexico burned out of control for weeks on end.

Now to cap it all off we have drought conditions that stretch just about from coast-to-coast, covering 56 percent of the country, which is a record extent for the 21st century.

The U.S. Climate Extremes Index, which hit a record high for the year-to-date due to the extreme weather so far in 2012. Click on the image for a larger version.

Wouldn't it be great if there was a way to see how all of these extremes, from record heat to flooding, stacks up against past years? Well, there is. The National Oceanic and Atmospheric Administration (NOAA) maintains a Climate Extremes Index for this purpose. It's somewhat complex upon first glance. According to NOAA, it tracks the highest and lowest 10 percent of extremes in temperature, precipitation, drought and tropical cyclones across the lower 48 states (sorry, Alaska and Hawaii). 

In other words, it shows the area of the U.S. affected by extreme weather conditions, be it extreme temperatures (hot or cold), or precipitation (be it heavy rainfall or very dry conditions). The fact that the index is at a record high indicates that more of the U.S. has been affected by extreme weather during the year-to-date than any other January to June period on record.

Not surprisingly, the Climate Extremes Index has been at a record high for the January-to-June period this year, with extreme weather conditions affecting 44 percent of the contiguous U.S. The main culprit is the record warmth, with record warm daytime high temperatures as well as record warm overnight lows affecting a huge part of the country. The heat has been unheard of, in some cases.

In Sidney, Neb., a whopping 20 daily record high temperatures were set or tied during June alone. And Norton Dam, Kan., broke an all-time record when the temperature soared to 118°F on June 28, beating the old record of 113°F, set three days earlier.

Record temperatures and drought conditions also drove the Climate Extremes Index to 39 percent in 1934. Many of the warm temperature records established in 1934 were toppled during the past few weeks. 

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