You are here
Special Report: Looking Down on Hurricane Dorian
Meteorologist Dan Lindsey is senior scientific adviser for the GOES-R satellite program with the National Oceanic and Atmospheric Administration (NOAA), https://www.noaa.gov/. He’s based in Fort Collins, Colorado.
SF: Are you watching Hurricane Dorian?
DL: I’m paying close attention to it. My wife’s parents live in Hilton Head, South Carolina, which is in one of the areas of mandatory evacuation. We hope it remains offshore. We will find out. Now that it has started to move, the National Hurricane Center has a pretty good handle on the track. It might come onshore somewhere in upstate South Carolina or maybe North Carolina. Luckily it has weakened since it was at its peak a few days ago. That’s good news at least.
SF: The photos of the destruction in the Bahamas are incredible.
DL: It’s truly unbelievable. It’s a complete catastrophe down there.
SF: Are you surprised at the destruction?
DL: No, not at all. It was a category 5 storm, which is as strong as they get in the Atlantic, and it sat there for multiple days. Even if it had gone right through it still would have caused tremendous damage. Sitting there just exacerbated it.
A lot of rain for North Carolina
SF: Farmers in the Carolinas are concerned.
DL: It looks like they will get a good bit of rain, but probably not as much as they did with Hurricane Florence last September. It came onshore in North Carolina, and then slowed down and generated a lot of rain. This one, at least, is now moving. It’ll generate a lot of rain, but I don’t think it will be quite the amount that Florence gave last year.
SF: Let’s talk about your area of expertise, the satellites that watch these storms.
DL: I work with the GOES series, which stands for geostationary operational environmental satellites. Geostationary means the satellite orbits at the same rate that the earth spins and is always looking at the same place above the equator. It is high enough that it sees the entire hemisphere.
There are four satellites in the GOES-R series, and the first two have been launched – 16 and 17. GOES-16 is focused mainly on the East Coast of the U.S. GOES-17 is centered over the east Pacific Ocean and covers Hawaii, Alaska, East Pacific, and the West Coast of the U.S. They constantly take pictures, which means we can see hurricanes spinning.
SF: Who uses these pictures?
DL: The forecasters from the National Weather Service and anybody that’s doing forecasting, such as the Weather Channel, AccuWeather, and other private companies. They rely heavily on the imagery and data from these geostationary satellites. They see the images at their computer screens within minutes of when they were actually imaged by the satellite. That’s especially important for things that are moving along pretty quickly, like thunderstorms, but not necessarily in the case of Dorian.
SF: What got you into this line of work?
DL : I grew up in Georgia, and when I was in high school in 1993 we had what was called the Storm of the Century. It was a huge snowstorm that went up the East Coast, and we got 16 inches of snow. That event made me get into weather. I was always into math and science, so it was a natural fit for me. I got a doctorate in atmospheric science from Colorado State University.
SF: Are those nor’easters similar to a hurricane?
DL: If you look at them from our satellites, they both spin counterclockwise, but there are fundamental differences. Hurricanes form over warm ocean water and once they move over land, they eventually die. The nor’easters, or mid-latitudes cyclones, form over land or over ocean and they don’t require the warm ocean water in order to thrive. They both can have strong winds, but hurricane maximum winds are stronger and they produce more precipitation. In the central U.S., the mid-latitude cyclones can dump a foot or two of snow and cause problems for farmers with livestock.
Other weather concerns this fall
SF: The fall is a busy weather season.
DL: The peak of hurricane season is September 15, so this is definitely prime hurricane season. We also start to get into the season for mid-latitude cyclones. In October and certainly into November we have a chance of getting early-season snowstorms in the central U.S.
The other thing we sometimes get in the fall is wildfires, especially in places like California. The satellites are really good at detecting the heat signature from the wildfires, as well as the smoke that they produce.
SF: When was this technology first developed?
DL: The first GOES satellite, GOES-1, was launched in the 1970s. There are usually one or two sending back data in real time. As the years go by, there are significant upgrades in the technology and instrumentation. The most recent, GOES-17, was launched in March of 2018.
Before we had satellites we had ships
SF: What did meteorologists rely on before the GOES satellites?
DL: There were a few other types of research-grade satellites before the GOES program, but if you go back before the 1960s, we had no satellites at all. We largely didn’t know where all the hurricanes were over the ocean. We had to rely on ships. If a ship happened to come across one and they radioed back the location, we knew where the hurricane was. Once they hit land, we knew where they were.
SF: Will there be more satellites launched?
DL: The next one, GOES-18, is scheduled for launch at the end of 2021. The last one, GOES-19, is scheduled for launch in 2024. Those will be our operational satellites into the early 2030s.
SF: Do the satellites you launch stay up there forever?
DL: They do. Eventually they will stop being used because an instrument dies. They have a limited amount of fuel and when they run out of fuel, we can’t maneuver them to keep them in the correct orbit. We move them farther away and put them in a graveyard orbit. They’re still out there floating around, but they’re so far away they’re never going to interfere with anything else because not much is orbiting at that altitude.
Are Rain Forecasts Getting Better?
SF: Let’s look at rain forecasting. Some farmers say they are getting less accurate.
DL: That might be a false perception. Forecasts, ever so slowly, get better with time. Meteorologists use numerical models to make forecasts. Those computer models are pretty reliable out to a week or so.
Our models have gotten a lot better over the last 30 years. Every year they get just a little bit better. Now, some years it may be more challenging for the models because a certain weather pattern might be slightly less predictable.
We can draw a box over a certain region and say this area may get heavy rain this week, for example. However, it is really hard to pick somebody’s farm in Iowa, for example, and say, you’re going to get 2 inches of rain over the next two weeks. Being that precise is really difficult. We can say we have a rainy pattern coming up and there’s a good chance that you’re going to get excessive rainfall somewhere in this area.
Sometimes little thunderstorms may hit one farm, but the next county over may get nothing. That means one farm may end up with what it considers an accurate forecast and the next farm over may not. That is the-hit or-miss nature of thunderstorms in the summertime. We can’t really pinpoint it.
SF: If there was a 10% chance of rain, and it rains, that forecast wasn’t wrong?
DL: That’s right. There's still a one-in-10 chance. Now, if you consistently say it’s 10% and it rains every day, that’s a pretty bad forecast. But in theory, if you say it’s a 10% chance and then it rains one in 10 days, that’s a correct forecast because you’ve correctly said there was one-in-10 chance each day.
SF: Is there anything else you would say to farmers?
DL: The weather forecasts they rely on will continue to get better with time. We will have better models and better observations provided by our satellites. It is a relatively slow improvement, but I do expect all of these things to get better as we move forward over the next 10 years or so.