The house that Jack built

This is the purpose-designed house that Jack built.
This is the Cray XC40 supercomputer that cost £97 million, has 1.6 petabytes of memory and runs over 16 trillion calculations per second that sits in the purpose-designed house that Jack built
This is the sophisticated NWP model, that runs on the Cray XC40 supercomputer, that sits in the purpose-built house that Jack built
This is the last night’s forecast produced by the sophisticated NWP model, that runs on the supercomputer, that sits in the purpose-built house that Jack built.
These are the actual temperatures for 04 UTC close to the house that Jack built.

In my reworking of the old nursery rhyme, Jack is of course synonymous with the Met Office, if you’ve not already guessed! What I’m trying to say I suppose is this:

You may have the fastest and the most accurate forecast model in the world, but if you can’t visualise what the model is telling you, then you may be just wasting your time.

These NWP  models generate so much highly detailed forecast data, a lot of which forecasters can’t possibly assimilate, and getting the salient facts about the weather across to the public, such as the overnight minimum temperatures seems to elude them. Compare the forecast temperatures in the graphic from the BBC with the actual temperatures at 04 UTC this morning, and you will notice that they are around 3°C too high in most of Devon. It makes no difference that the Cray XC40 supercomputer is located just 2.26 km to the west of the airport, and even though the mesoscale output from the model may have correctly forecast the temperature at 04 UTC, the BBC graphics are still wrong.

Some may argue that the temperature that the BBC show are for “towns and cities”, but that to me is just a clever get out on their part. There is a problem forecasting extreme temperatures, especially overnight minimum temperatures which has never successfully been resolved, in fact I would say that little effort has ever been expended either by the Met Office, or the company that provides the BBC graphics in doing so. Let’s hope that Meteogroup, in these days of 4K television, come up with an improved way of displaying extreme temperatures which more accurately reflects what the model is  forecasting when they finally take over the service next March.

Author: xmetman

An ex-metman passionate about all things to do with weather, climate and clouds

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