Commentary: CoCORaHS observers changing weather research

Daily Record (Rochester, NY), Sep 18, 2008 by Kevin Williams

Reconstructing the past weather has always required, in part, the skills of a detective.

Uncovering every bit of useable weather data is essential to providing the most accurate and complete picture of a previous weather event.

Analyzing past weather for remote locations can be especially daunting due to the distance from reliable, hourly airport weather observing stations. To compensate for this paucity of useable airport data, forensic meteorologists use a variety of other data sets, including satellite imagery, doppler radar imagery, National Weather Service snow spotters, police road reports, media weather watchers and the cooperative weather observation network.

The cooperative observer network has filled some holes in actual surface observations by providing once-daily measurements, but large areas remain uncovered by either airport data or coop data. In fact, in some counties such as Monroe, there are no cooperative observers at all.

There is, however, a new and exciting data source emerging to help fill in the gaps.

A national weather observing network is expanding throughout the country -- the "Community Collaborative Rain, Hail and Snow Network," otherwise known as "CoCoRaHS." It is now composed of 11,000 observers in 34 states who measure all forms of precipitation.

CoCoRaHS is a program that is expected to greatly assist weather researchers as the network of stations will become sufficiently dense to catch the small scale weather systems that often occur between primary airport observing stations. It was developed by Colorado State University meteorologists in 1998 who were inspired by a flash flood at nearby Fort Collins and the need to garner more information about the event.

Today, with the coordination from the Northeast Regional Climate Center at Cornell University, a call is being made to amateur weather watchers in New York State to participate in the new network.

Cornell's Kathy Vreeland tells me there are about 100 actively reporting CoCORaHS observers in New York, with 50 new stations online in Erie County. Kathy and my other colleagues at Cornell would like to see similar success here in Monroe County and in adjacent counties.

Anyone with an interest in the weather and access to the Internet can sign up. The only equipment needed is a cylindrical rain gauge, available from the network for $22 plus shipping. Training is available through the organization, with additional information available at www.cocorahs.org.

The new data that will be made available via CoCoRaHS will allow researchers and forensic meteorologists to more accurately place the location and intensity of small scale weather features, such as thunderstorms and lake effect snow squalls.

For attorneys here in Western New York, the new data means more confidence can be placed in those meteorological reports that identify and describe local precipitation systems such as the placement of lake effect snow bands and the accretion of freezing rain in remote locations not well served by observing stations now in place.

Kevin Williams is president of weather-track.com and director of meteorology for News 10NBC.