Importance of weather balloons for severe weather forecast
5th Season: DAY 5
NORMAN, Okla. (KSWO) - In the late 1930s, an international agreement was set that twice a day, every day, more than 800 weather balloons are launched into the air by meteorologists worldwide.
But the significance of a weather balloon and its purpose to serve is to help understand the atmosphere.
But what is the significance of a weather balloon, and what purpose does it serve in helping us understand the atmosphere?
First Alert Meteorologist Lexie Walker went to the National Weather Service (NWS) forecast office in Norman to show how it helps the First Alert Weather Team forecast severe weather events.
Weather balloons carry an instrument called a radiosonde into the atmosphere which transmits data points of humidity, temperature, wind speed, wind direction and atmospheric pressure at different elevations.
Once the flight is finished, the data is analyzed by Forrest Mitchell, the Observations Program Leader for the NWS forecast office in Norman, and sent to the National Center for Environmental Prediction (NCEP) in Maryland.
“At the national level, it’s ingested along with data from all the other upper air flights around the world,” he said. “The end result gives us a picture of the atmosphere in a moment in time. And then the computer-generated forecast models gives us a range of possibilities of what the weather could do based on these flights.”
From there, it’s a meteorologist’s job to decide what the weather is based on these forecast models. Weather balloon launches are important, because while there are thousands of weather stations across the county that measure observations at ground level, they are extremely limited.
“Severe weather season is not just measuring the actual readings, as the instruments being carried, it’s the rate of the change that’s critical for us recognize so we can fine-tune the forecasts and be better prepared to understand the potential of what a particular severe thunderstorm may do,” Mitchell said.
Thunderstorms thrive on warm, humid air, instability of the atmosphere and some sort of lifting mechanism, usually a cold front. When forecasting for tornadoes, there needs to be changes in wind speeds and direction with height.
“We call that wind shear,” Mitchell said. “Certain amounts of wind shear with height, in the lowest 12,000 feet of the atmosphere, gives us valuables clues as to the risk of whether or not we will be looking at a significant tornado event.”
While there are other ways to get upper air data such as satellites, drones, commercial airplanes, and experimental gliders, Mitchell said after all these years launching a balloon into the sky is most dependable.
“Listen, it’s really quite amazing that after 80 years, the old reliable method of inflating a balloon with a lighter than air gas to carry up an instrument,” Mitchell said. “That’s still the primary means of measuring the atmosphere around the world and a very critical tool for the forecast process.”
Often times in the spring when there’s a risk for severe weather, the Storm Prediction Center, also located in Norman, will request special flights during the early afternoon to help measure the rate of change to determine the exact risks later that day.
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