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United States Science Technology

The Long-Awaited Upgrade To the US Weather Forecast Model Is Here (arstechnica.com) 59

An anonymous reader quotes a report from Ars Technica: For the first time in about 40 years, the guts of the U.S. model got swapped out for something new today. The upgrade brings us a new "Finite-Volume Cubed-Sphere" (or FV3) dynamical core, which simulates the basic atmospheric physics at the heart of this endeavor, a change that has been in the works for a while. The new core had its origins in simulating atmospheric chemistry but ended up being adapted into other models. A few years ago, it was selected to replace the old core in the U.S. Global Forecast System model. And for more than a year now, the new version of the model has been running in parallel so its results could be compared to the operational model.

The results have been a little mixed. The new core improves computational efficiency and allows some processes to be simulated at a higher resolution -- unequivocal improvements. It also simulates the physics of water vapor more realistically. In a press conference today, NOAA scientists cited a number of areas where forecast improvements have been seen. Forecast tracks of hurricanes and the mid-latitude storms that frequently sweep across the U.S. have both improved, they said, along with forecasts of hurricane strength. Forecast precipitation amounts were also cited as a key area of progress. But there have also been grumblings in the weather community over the past year about results that didn't seem so hot. For example, surface temperatures have been biased low in some situations, throwing off forecasts.

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The Long-Awaited Upgrade To the US Weather Forecast Model Is Here

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  • by Anonymous Coward
  • Pity it'll be fucked when 5G comes out and ruins the data going in to the model.

  • And I thought that squaring a circle was hard enough.

    https://en.wikipedia.org/wiki/... [wikipedia.org]

    • Seriously, though, the thing about squaring the circle is that it has to preserve area. The issue in this case is that you need to come up with a well-behaved grid that covers the planet, with as little distortion as possible and with no singularities. Especially without any ill-conditioned volumes close to any place where important weather-generating activity happens, like the poles.

      At any rate, you can't use a single 2D grid because of hairy ball theorem [wikipedia.org].

      Yes, that joke you're thinking of right now has alr

  • The upgrade brings us a new "Finite-Volume Cubed-Sphere" (or FV3) dynamical core, ...

    Because the old "Infinite-Density Squared-Torus" (or IDT^2) static shell took too long to compute -- and no one knew what *it* did either.

  • Shows that the climate changes?
  • Trolls-Check; TDS-Check; Climate religion wars (both sides)-Check; Information-Total fail. Adult discussion-Total fail.
    • Moderation idea (Score:3, Insightful)

      by SuperKendall ( 25149 )

      Adult discussion-Total fail.

      Slashdot should post one story like this a month, where every social reject is drawn in and as you say, nothing is said though a lot of words are posted.

      After several hours have passed, Slashdot removes the story and IP bans all users who have posted.

      Ahh, bliss.

  • ...is crowdsource the data a bit more. Sucks when the forecast says "20% chance of rain" and it's pouring outside, and the actual weather is 5 degrees off the forecast prediction.

    • This always made me wonder too, but my local meteorologist explained it to me a couple years ago. He even provided a link that I can't find at the moment. The temperature is usually at a specific location, typically "at the airport" where I live. And the chance of rain is over a given area - the viewing area for tv weather. So there is a 20% chance that it is raining somewhere in that area. Lucky you happens to be in that area so you're seeing rain. The question I still have is: Is it a 100% chance tha
  • I like the NOAA site, but from mid-June through mid-September, on any given afternoon you can look at the charts and they will say "Forecast: high of 85" but then you dig further and see "Currently 92." I laugh and shake my head, but it happens nearly every day. You'd think they'd make adjustments or at least update the daily forecast to realize that if it's overshot by 7 degrees, that should be the new, amended forecast.

    This is probably unrelated to the new spherical cube thingy, but this cranky aging man

  • The new core improves computational efficiency and allows some processes to be simulated at a higher resolution -- unequivocal improvements. It also simulates the physics of water vapor more realistically.

    The weather report was fairly useful where I lived last, in Kelseyville. Now I'm in Albion, and it's completely worthless. I mean that literally, I get more useful information by just going outside. Or hell, looking outside. But this is a complex environment with hills and a lot of marine influence, so it's not surprising if nobody can predict my weather accurately. My guesses would be that the resolution and the modeling of water vapor would in fact be the specific big problems with modeling it.

  • ...the ECMWF?

  • It's not "the" US model, it's "A" US model, specifically the GFS. There are multiple models; the GFS, HRRR, HREF, RAP, NAM....

    It's comical that people are complaining about model accuracy but can't be accurate about which one they're complaining about.

Truly simple systems... require infinite testing. -- Norman Augustine

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