For decades, the National Weather Service has released weather balloons at a clockworklike cadence at more than 100 sites across the country, as well as over the Pacific and the Caribbean.
Twice a day — at 8 a.m. and 8 p.m. ET — meteorologists simultaneously launch the balloons, which are equipped with instruments called radiosondes that measure temperature, humidity and wind speed. They rise about 15 feet per second for two hours, traveling through layers of the atmosphere and sending pings of data back using radio waves.
When the air gets too thin, the balloons pop and fall back to Earth with little parachutes — mission complete.
Data from the balloons feeds into weather models that are the backbone of forecasts across the United States, whether they’re delivered by a local television broadcaster or on your iPhone.
But many of the release sites — at least 10 in the continental United States — have suspended or limited launches because of the Trump administration’s cuts to the National Weather Service staff.
Meteorologists and weather balloon experts say the change will reduce forecast quality and increase risk during severe weather.
“There’s no question it will lead to errors. It’s just a matter of how bad will it be,” said Matt Lanza, a meteorologist in Houston who writes for “The Eyewall” blog. “We know these things help with forecasts, so why are we cutting them?”
The National Weather Service cuts are part of the Trump administration’s widespread downsizing efforts across federal agencies. At the National Oceanographic and Atmospheric Administration, which includes the National Weather Service, more than 600 workers were fired, then reinstated, at least temporarily, after a court ruling. At science agencies overall, the administration has cut federal workers, slashed budgets and targeted diversity and equity programs.
News of weather balloon reductions has trickled in over the last month. The NWS first said it would suspend balloon launches in Kotzebue, Alaska. Then it said it would miss some launches in Albany, New York, and Gray, Maine. Last week, it added Omaha, Nebraska, and Rapid City, South Dakota, to the list of cancellations. It also limited flights to once per day at sites in Colorado, Michigan, Nebraska, South Dakota, Wisconsin and Wyoming. The notices all cited staffing as a reason.
Susan Buchanan, an NWS spokesperson, declined to answer questions about the changes.
“The Public Information Statements we released contain all the information we have to offer at this time,” she said in an email.
Several meteorologists said the balloon launch reductions are concentrated in parts of the United States where data is especially needed.
“The really unfortunate thing is, where these balloons are now missing — the Colorado Rockies, the Wyoming Rockies, the northern and central High Plains — is where a lot of severe weather happens in the spring and summer months and [where] a lot of the storms that will impact the Great Lakes and Eastern United States first develop,” said Chris Vagasky, the research program manager for Wisconet, a network of weather and soil monitoring stations across Wisconsin.
Storms generally track from west to east in the United States, so weather balloons often provide reads on what can be expected downwind in the hours and days after they fly.
The balloons provide the finest-resolution data about different layers in the atmosphere — information that can’t be easily replicated by satellites or other equipment — so without them, scientists could be left guessing about the type of precipitation that will fall, for example.
“Here in New York, we often have very messy weather systems where they start as snow and turn into sleet and then freezing rain and rain,” said Nick Bassill, the director of the State Weather Risk Communication Center at the University at Albany in New York. “We might have just one little thin layer that bumps you up above freezing, then suddenly your snowstorm turned into a rainstorm or freezing rainstorm.”
The balloons are among the most important sources of data for weather models, he and other forecasters said. When they compared various instruments used to aid forecasting, NASA researchers found that radiosondes had the second-biggest impact on forecast quality, after satellites.
Bassill said meteorologists typically wait to run weather models — which produce estimates of temperature, wind speed and other meteorological data — until after a balloon has launched.
“That’s when you have the most data that you can give the model,” Bassill said. “Data that are collected in real time from these goes pretty much straight into weather models.”
Vagasky, who previously worked for the Finland-based manufacturer of the weather balloons the NWS uses, Vaisala, said it’s not unheard of for the weather service to stop launching balloons at a site temporarily. For example, it decommissioned a site in Chatham, Massachusetts, because of coastal erosion. Helium shortages also led launches to be stopped in Denver and Tallahassee, Florida, over the past few years. (Balloons use helium or hydrogen, but in densely populated areas, meteorologists avoid hydrogen because it is flammable.)
But between previous stoppages and the recent cuts, Vagasky said, “we’ve gone from 200 balloons in the weather service network each day down about 15% in the last few years.”
That will leave forecast models without key data, he said.
Without any weather balloons, Vagasky said, today’s forecasts would be about 15% worse, citing NASA data.
Russia once tried to cut its radiosonde launches in half, from January to April 2015, and European forecasters saw a decline in their model’s forecast quality.
The U.S. reduction is less dramatic, so it will take some time for scientists to tease out its statistical impact. Bassill said that he suspects most people won’t immediately notice a day-to-day difference if they’re using weather applications on their phones but that there will be more surprises.
Some private companies are trying to help fill newly opened gaps in the National Weather Service’s system. The startup WindBorne, which is developing a network of low-cost, long-range balloons to monitor hard-to-reach areas, offered to provide the NWS some of its data from Alaska after launches stopped at Kotzebue.
John Dean, a co-founder of WindBorne and its CEO, said he was surprised and concerned about the cuts to National Weather Service radiosondes. Dean said his company is working out logistics with NOAA to feed additional data to the agency for six months through an existing contract at no cost.
But Dean said private businesses are unlikely to replace the service NOAA has provided. His company’s goal was to add coverage, not replace it, by expanding balloons to the 85% of the globe that he said is poorly monitored.
“We’re not ready to fully replace radiosondes now, and it’s not obvious that we ever will be,” Dean said, noting that most private weather companies rely on NOAA data and models. “I don’t think you’d see any kind of private company wanting to see NOAA services degraded.”