Overkill

absurdly advanced tech, explained badly, used for dumb stuff

All overkills

Weather

or: simulating the whole sky to pick a hoodie

Twice a day, every day, we let go of balloons from about a hundred spots across North America that float 100,000 feet up1, radioing back the temperature, humidity, and wind the whole way, while satellites parked 22,236 miles above the equator2 stare at every cloud on our half of the planet. Then we pour all of it into a pair of supercomputers that can do 29 quadrillion calculations a second3, simulate the entire atmosphere into the future, and get the next five days right about 90% of the time4.

And we use it to decide whether to bring a hoodie.

How it works, badly

  1. #
    bye! write homefrom 100,000 ft
    Twice a day we let go of balloons that float 100,000 feet up.
  2. #
    22,236 milesyep. clouds.
    Satellites 22,236 miles up stare at the clouds.
  3. #
    the wholesky, tomorrow29 quadrillion math problems a second
    Supercomputers simulate the entire sky, tomorrow.
  4. #
    40% chance of rain.hoodie it is.
    Then we use it to pick a hoodie.

Wait, is that real?

Yes, and the balloons are not a metaphor.

The balloons↩

The National Weather Service launches radiosondes from 92 stations across North America and the Pacific, plus 10 more in the Caribbean, twice a day at the same two times. Each balloon starts about 5 feet across, swells to 20 to 25 feet as the air thins, and usually climbs to around 100,000 feet before it pops. The instrument box measures pressure, temperature, and humidity, and its GPS track gives the wind.

The satellites↩

NOAA’s GOES weather satellites sit in geostationary orbit, 22,236 miles above the equator, circling at the same rate Earth spins so each one watches the same half of the sky nonstop.

The supercomputers↩

NOAA runs its forecast models on two supercomputers, Dogwood in Virginia and Cactus in Arizona, at 14.5 petaflops each. Together that’s about 29 quadrillion calculations a second.

How right it is↩

NOAA puts a five-day forecast at about 90% accurate, seven days at about 80%, and ten days or more at roughly a coin flip.

The fine print↩

“About a hundred spots” is 102 if you count the Caribbean, and “every cloud on our half of the planet” takes two satellites, GOES East and GOES West. The 29 quadrillion is both computers added together. “90% accurate” is a rough rule of thumb, not a guarantee about your specific picnic. And the forecast also warns about hurricanes, floods, and tornadoes, which is arguably more important than the hoodie.

Sources: NWS: weather balloons; NOAA: GOES-18 reaches orbit; DCD: NOAA supercomputers upgraded; NOAA: how reliable are forecasts?

Last fact-checked .