Advances in Weather Radar Since AccuWeather Was Born

By Jim Dickey
9/3/2013 10:32:00 AM

Radar is an invaluable tool that meteorologists use to monitor and forecast the weather. From seeing where rain is heaviest, finding where snow is falling or even pinpointing the turning winds of a tornado, radar technology has firmly established itself as one of the primary tools meteorologists use to help protect life and property.

Through the 50-year history of AccuWeather, radar technology has come a long way.

The use of radar in meteorology began more or less by accident, during World War II. Meteorologists in the Navy found that, along with the ships and boats military radars were designed to detect, the radars also picked up on clouds and precipitation.

"I noticed, of course, every cumulus buildup that had a shower in it showed up on the radar, for the use they had of it, it was a nuisance. But to me, that was interesting," said Dr. Charles Hosler, who served in the Navy during WWII. When meteorologists like Dr. Hosler returned home from the war, they began research on the usefulness of radar in meteorology, and slowly but surely, its use expanded.

During the late 1950s, after a series of undetected hurricanes struck the U.S., the government began the installation of the first national radar network, dubbed the WSR-57. By the end of the 1960s, over 30 of these radars had been installed.

To fill in gaps in coverage and to upgrade failing radars, the government expanded the national radar network with WSR-74 models. And while this expansion certainly increased coverage across the country, still large gaps of space across the Rockies and West Coast remained uncovered.

As Pennsylvania State Climatologist Paul Knight explained, the images produced by these early radar systems left much to be desired as well.

"In the '60s and '70s, it was very crude. The dishes and the dials, we couldn't control very much, and most of the time, when we had them, there was just this rough paper copy where we essentially had to make a like a flip chart cartoon to be able to see any motions," he said.

Radar is crucial for forecasting severe weather, including detecting tornadoes, high winds and large hail. A tornado was first captured on Doppler radar near Union City, Okla., on May 24, 1973, according to NOAA.

The latest expansion began in 1988, as the remaining WSR-57 and WSR-74 systems were upgraded through the WSR-88D network. These radars expanded coverage across the entire CONUS and also included doppler technology. Doppler technology allows meteorologists to 'see' wind speed and direction along with reflectivity, a crucial factor in tornado detection and warning.

Of course, through the advancement of computer technology, radar imagery improved greatly over the years as well, from the grease pencil images of the past to the sophisticated imagery of today.

Doppler radar sends out a pulse of energy, which then intersects precipitation. The amount of energy reflected back to the radar is proportional to the intensity of the precipitation falling.

A national network of NEXRAD Doppler radars was installed in the U.S. during the early 1990s. Countless number of lives has been saved by meteorologists' ability to detect tornadoes across the U.S.

"Since its introduction, NEXRAD has decreased the number of tornado-related deaths by 45 percent and personal injuries by 40 percent," NOAA said.

Radar technology continues to improve today. Dual polarization radars are the next upgrade to Doppler radars, and they are currently being installed across the U.S. Better detection of precipitation type in clouds will help improve precipitation measurements and the recognition of hail. Forecasting for flash floods will be significantly improved as a result of this data.

And now, what started as technology available only to the military can be viewed on an average cell phone.

Content contributed by AccuWeather meteorologist Meghan Evans.