Daniel Gropper Gauges the Weather

For most of us, “weather happens.” But for Daniel Gropper, it does much more than that. And when it comes to severe weather, well, this trained weather spotter and Skywarn team member admits, “Oh, yes, it's my passion!”

Gropper witnessed his passion firsthand on August 24, 1992, when Hurricane Andrew headed for the National Hurricane Center in Miami, FL. The National Weather Service (NWS) asked Skywarn, a group of amateur radio operators and trained weather spotters, to set up a radio link from the Miami center through the Baltimore/Washington weather forecast office to hurricane specialists in Camp Springs, MD. Gropper guided the Skywarn team.

“I spent the night in the forecast office and listened to Miami's 1:00 a.m. conference call. The winds were howling in the background,” he remembers. “The center was down to one telephone line and the winds were gusting to 164 mph…then Andrew blew the radar off the top of their building.”

Gropper's introduction to Hurricane Isabel last September was far less dramatic. By the time the hurricane reached his home near Washington, DC, winds had dropped to about 40 mph and rainfall measured about 2 inches. Gropper spent much of his time monitoring emergency services broadcasts and consulting with medical emergency workers. Of course, whether the hurricane is Andrew or Isabel, communication is key.

The Skywarn network started in the 1970s as a way to inform the NWS (see below) about severe weather across the nation and to coordinate emergency management information with the Red Cross and local governments. Gropper joined in 1989, when Doppler radar was in its infancy.

“Regular radar sees a cloud…period,” Gropper explains. “Doppler can zoom in on a storm and see a cross section of the storm's structure. It can see wind speed and direction.” Weather forecasters figured out exactly what the Doppler system could do by comparing what they saw on the radar screen with what weather observers told them was actually happening in real time. They discovered that Doppler could detect the point where snow changes over to rain, which, according to Gropper, “was a major surprise to everyone.”

Gropper received a Public Service Award from the NWS for his work with Skywarn and for training others in emergency communication practices. He got a similar award from the Baltimore/Washington weather forecast office. Gropper's fascination with severe weather started when he was a boy in Oceanside, NY.

“I grew up on boats and next to the water. Weather is critical to boating safety,” he says.

Starting in his teens, Gropper played clarinet in the fire department band. Later he became a firefighter. An early interest in science and engineering was sparked when he studied the emergency communications equipment in the fire department's dispatch office.

“I installed a fire radio scanner on my bicycle. One day I was out riding and a call about a kitchen oven fire was transmitted. I was in front of the house with the fire. I rang the doorbell and asked the lady if she had called the fire department. She had, so I looked at the oven and it was a small electrical fire. I turned off the circuit breaker and left. The next day this lady runs into my mother and tells her that she called the fire department and said she had a small fire and not to send too many people…but she never expected them to send a kid on a bicycle!”

Combining his passion for weather and curiosity about emergency communications, Gropper bought a weather radio when one of the nation's first weather radio transmitters went on the air in New York City. And he joined Skywarn.

“When I was the Skywarn coordinator, I noticed that severe weather alerts were being transmitted, but were not being received by the fire departments and emergency services. So I created a receiver that would place weather alerts on fire/emergency radio channels without interrupting operations.”

Gropper became a patent attorney and started Thunder Eagle, a company that produces NOAA (National Oceanic and Atmospheric Administration) weather radios. These receivers allow you to get information about severe weather in counties you select and to automatically send a message to the NWS that the alert was received. This system is also used for missing children alerts and certain national security events.

As a member of the NWS's Cooperative Observer Program (COOP), Gropper starts his day by measuring the weather in his own backyard in Vienna, VA, where he lives with his wife and two children. Congress created COOP in 1890. Now, more than 11,000 volunteers across the United States take daily observations of the weather in almost every locale you could imagine.

Gropper began volunteering about nine years ago, when a COOP volunteer in his city retired after nearly 50 years. The NWS installed temperature sensors and a rain gauge in his yard, and showed him how to use them. Gropper also put a thermometer, anemometer (wind gauge), barometer, and rain gauge on his roof. He records daily observations in a weather log and uses the telephone keypad to send data to the NWS.

“The daily observation needs to be submitted to the NWS every day by 8:00 a.m.,” Gropper explains. This includes 24-hour maximum and minimum, and current temperatures, 24-hour precipitation amount, and type of weather.

“If severe weather is occurring, I'll call the report in as needed, often in the middle of the night,” he says. “During an incredibly heavy rainfall (almost 8 inches), I measured the rain every two hours through the night and reported my observations to the NWS so that they could do accurate hydrological forecasts for flooding.”

His nemesis is ice. Gropper recalls his scariest COOP moment, which happened while trying to measure one inch of ice. He slipped and careened down the driveway, clutching his ruler.

What happens when Gropper is out of town? “I've trained my family to do the reporting,” he says. “If we are all away, I have friends trained as backup. The neighbors love that I am a weather watcher and often call me for the details of my observations. They enjoy it when they see my observations on the local TV news.”

Long before COOP was formally established, many famous and not-so-famous people recorded the weather. Gropper enjoys linking Thunder Eagle and modern weather technologies with the past.

“I like knowing that I do what George Washington, Ben Franklin, and Thomas Jefferson did,” he says. “The weather affects all of us every day. It's great to be a trained observer and appreciate the wonder of weather while at the same time helping the entire country (and world) with small bits of accurate weather data.”

Thomas Jefferson started recording the weather in 1776, when he was 33, and kept at it for 40 years. Daniel Gropper started recording the weather in his thirties, too. Gauging from his passion for severe weather, Gropper might continue his observations even longer than Jefferson!


A very large, indefinite number.

A source of harm or ruin.

Back to Top


  1. How many people volunteer to take daily weather measurements at home and send their information to the NWS?
    [anno: About 11,000 people volunteer to take daily weather measurements to send to the NWS.]
  2. What might happen if no one volunteered to take these measurements?
    [anno: Answers will vary but could include that the weather reports might be less accurate. The NWS might not be able to predict certain conditions, such as how high a flood might get in a particular area. The government would have to spend more money to monitor the weather.]
  3. Write a short paragraph about a time when the weather affected your day or your week. What kind of weather was occurring? How did it affect your plans? Would you have changed your plans if you knew what the weather was going to be on that day or week?
    [anno: Answers will vary.]