# Dogwood and Cactus add up!

Whenever I speak, I invariably am asked which computer model is best, the American (GFS) or the EURO (ECMWF) to which I shrug and give examples of which computer did better at which times.

I will say that Hurricane Laura comes to mind when the GFS never varied from a Louisiana strike while the EURO had Texas in its sights for a while. Then, with Hurricane Ida, the EURO didn’t vary much from a southeastern Louisiana strike while the GFS eventually caught up to that idea. They are both excellent models and you just have to see which gains your confidence with a particular storm as each forecast is made. At the end of the day, it’s all about how much weather data your computer can reliably and quickly calculate to come up with a forecast!

If your dad was anything like mine, then you’ve heard this on a Saturday morning: What is this, a flophouse? But in the world of computers, the more flops, the better because the more flops, the faster the computer runs! FLOPS stands for FLoating-point Operations Per Second. Think of a FLOP as one calculation and weather data is all about calculation. The more physics equations a computer can solve and the faster it can solve them reliably, the better and more quickly the forecast it gives us.

### The New American Model

This brings us to the brand new American model. First announced in 2020, the model went online yesterday with more than three times the computing power of the last one! Just how much power? Well, there are TWO computers -- one in Virginia and one in Arizona -- and each operates at a speed of 12.1 Petaflops! WAIT.....what’s a Petaflop??

Back to the flophouse: one FLOP is, well, one calculation. A megaflop is likely what your home computer runs and that’s a million calculations per second. From there, we can increase by a thousand to get to GigaFlop which can perform a billion operations per second. Above Giga we have TeraFlops performing a trillion calculations per second. Then there is the mighty PetaFLOPS -- one QUADRILLION equations per second. That went up fast!

What’s a Quadrillion? A one with 15 zeros behind it! 1,000,000,000,000,000. You can read more on FLOPS right here.

And our new American models can perform 24 of these! That’s 24 Quadrillion floating point operations per second! Factor in computers in other parts of the country on the same system for another 18 PetaFlops and we get a total of 42! That’s a mighty bit of computer.

The new computers will not only enhance the current American model (GFS) but will launch a new hurricane-specific model in 2023 called the HAFS (Hurricane Analysis and Forecast System). I’m so excited, I’m flopping my wings! More on the upgrade is right here.

### The EURO upgrades too

Never to be outdone, the European Model (ECMWF) has a new Atos BullSequana XH2000 online (four of them, in fact) and are currently training on the system and putting it through reliability and stability performance trials. The system boasts five times their former computing power with over one million processors. Their flophouse? Thirty PetaFlops and expected to be operational in 2023. You can read more here.

All of this is great news for you and me -- the ones who need as much accurate forecasting as we can get. Perhaps one day soon, the answer to which computer model is better will simply be that they are both tremendously accurate.

By the way, the new American computers are named Dogwood and Cactus, referencing their locations in Manassas, Virginia and Phoenix. Take that you big European BullSequana!

Eye to the rainy sky the next couple of days. We’re on it!

Frank

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