Trees blocking critical radar data - WAFF-TV: News, Weather and Sports for Huntsville, AL

Trees blocking critical radar data

Radar image indicating beam blockage. Radar image indicating beam blockage.
HUNTSVILLE, AL (WAFF) - One of the most important parts of the severe weather warning process has been the advancement of the NEXRAD Doppler radar network, a government network that covers the entire country.

But one of those radars isn't functioning properly right now.

The NEXRAD network is made up of radars placed equally apart to track incoming weather from one coverage area to another. Multiple radar sites are needed because as the radar beam goes out across the land, it gets higher and higher. At a certain point, it can no longer see any useful information within thunderstorms. The closest radar to the storm provides the most reliable information. When it comes to tornadoes, the closest radar has the most important data, and meteorologists aren't getting data from one radar site.

On Oct. 13, a spin-up tornado hit Tuscumbia. Winds reached 105 miles per hour, and an uprooted tree crashed into a historic home, sending two people to the hospital.

The warning for that tornado came five minutes before the storm hit, but the National Weather Service didn't issue the warning based on radar images. The team issued the warning based on research and history with the type of storm that was tracking into the Shoals.

There is a problem at a radar site near the Air Force base just north of Columbus, Mississippi. Trees are blocking the radar, obstructing the view from the road.

Even though the radar is in Mississippi, it's an important tool for tracking storms and issuing warnings in Alabama and it's part of the NEXRAD system.

"The one that was put in the Columbus Air Force Base covers a portion of Mississippi, but was also strategically located to cover west central and northwest Alabama," said Chris Darden with the National Weather Service.

A functioning NEXRAD radar in Birmingham showed a well defined line of storms moving in from the west with the Oct. 13 storm system. From the radar site near the Columbus, Mississippi site shows a breakdown in the data. There were several areas with a spike and holes in the data. The problem becomes magnified the farther you move away from the radar.

"It's causing some issues in terms of being able to assess the strength of the storms and the potential severity," said Darden.

The areas shaded in red and yellow show the specific areas where the trees block the radar.

Mike Melton is the Colbert County EMA director. He said the trees likely contributed to the delayed warning in October.

"If we were tapping into Columbus, we may have been able to warn people a little bit sooner," he said. "What concerns me is this storm may have been the result of them not seeing it until it intensified enough for Hytop to see it."
Hytop is a radar site about 115 miles from the Shoals. If a radar site is more than 75 miles away from a storm, it becomes more difficult to see the storm.

There are a couple of options to fix the problem. One would be to raise the radar dish. That would cost around $1 million, but it's a quick fix. Once the trees grow again, the problem would persist. It would also raise the dish above the recommended height for weather forecasting data and would put the radar out of service.

The simple solution would be to cut down the trees. That's where the Department of Defense comes in. The DoD leases the land from a private land owner and has to pay the land owner before taking down the trees.

Because those negotiations are private, there is no information on the status of the deal. While the negotiation plays out, North Alabama is in the middle of the secondary severe weather season.

And the spring severe weather season will arrive soon - a season proven to be deadly, especially in western Alabama. On April 27, 2011, the deadly EF5 long track tornado that hit Phil Campbell and tracked all the way into Madison County originated in Mississippi.

"Those trees will keep getting a little bit worse and a little bit worse until they cut us off," said Melton.

Senator Richard Shelby responded to a request for comment on a solution for this problem. His office immediately called the DoD. Shelby said he's concerned about anything that could impede meteorologists' ability to prepare for storms in Alabama, especially as the primary severe weather season approaches. While there is no direct role for Shelby at this stage in the process, his office will stay in touch with the DoD.

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