Answer Man: In weather forecasting, what are the 'Euro model' and 'U.S. model?'

John Boyle, Asheville Citizen Times
·4 min read

Today’s batch of burning questions, my smart-aleck answers and the real deal:

Question: Whenever it’s going to snow or we’re in for a “wintry mix,” I see on the TV news a lot of references to “the Euro model” and the “US model” (or GFA, or something like that. I think it’s NOAA’s). Some meteorologists lean toward the Euro model and some toward the American one. What is the Euro model? How’s it’s calculated? What are the major models these guys use? Is one more accurate than the other? Also, sometimes they’ll say we’re going to get a “wintry mix” when the temps are going to be below freezing. Why isn’t it all just snow?

My answer: In the time it took to read this question, I downed two loaves of bread and a gallon of milk. It was like some weird wintry mix reflex or something.

Real answer: These are all fancy computer models for predicting the weather. So this answer is going to get a little complex.

When it comes to forecasting, weather professional consult a variety of computer models. Two of the most well-known are the "European model" and the "GFS," which the National Weather Service and National Oceanic and Atmospheric Administration create.
When it comes to forecasting, weather professional consult a variety of computer models. Two of the most well-known are the "European model" and the "GFS," which the National Weather Service and National Oceanic and Atmospheric Administration create.

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For that you can thank David Easterling, director of the National Climate Assessment Technical Support Unit, part of NOAA's National Centers for Environmental Information in Asheville. Hey, even his title is complex.

"Numerical weather forecasting models, like the 'European' or 'U.S.' models are complex computer models that run on supercomputers and provide a set of 'predictions' for what the weather is expected to do over the next 10 days or so by solving a set of equations at thousands of locations all over the globe," Easterling said via email. "The European and U.S. models are global models in that they provide predictions for the entire globe."

The National Oceanic and Atmospheric Administration/National Weather Service developed the U.S. model, which is technically called the Global Forecast System, or GFS.

"The European model was developed and is run by the European Center for Medium Range Weather Forecasting in Great Britain," Easterling said. "ECMWF is funded by the European Union, but each European country has its own weather service, like our NWS."

So, why do the two models vary?

"Since the ECMWF model and the GFS model are formulated a little differently, they can give different predictions," Easterling said. "Usually, the differences are things like the timing or exact track of an event, like a winter storm. In some instances, the GFS performs better, and in others the ECMWF performs better."

If you check out the "forecast discussion" at the National Weather Service office at Greenville-Spartanburg Airport (https://www.weather.gov/gsp/), Easterling notes, "you will often see the forecaster talking about how the timing or track of a storm differs between the two models.

"The forecasters use all this information, plus their own local knowledge to put together the forecast," Easterling said.

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As far as how we can get a "wintry mix" when the air temperature at the surface is below freezing, Easterling said, "Often there is a layer of air higher up in the atmosphere that is warm and melts or partially melts the snow.

"If the layer is high enough up and the air lower down near the ground is below freezing, the snow melts then refreezes into sleet," Easterling continued. "If the warm air is closer to the ground, the melted snow doesn't have enough time to refreeze, and it can become super-cooled (below 32F, but not frozen) and freezes on contact with the ground, or objects like power lines, thus becoming freezing rain."

Let's hope we avoid that...

Question: I just returned from my post office on Tunnel Road. A large portion of the ceiling in the customer service area has fallen, and water is dripping down into about 10 trash cans on the floor. Pretty soon we will need hardhats to enter. I know the Postal Service is in bad shape, but this is unsafe! What is the plan to fix this?

My answer: First, they'll have to send a work order to Greenville, South Carolina, then initiate a bidding process for contractors, and maybe contract for an environmental study. In short, it wrap up by 2055.

Real answer: "The Postal Service leases this facility and has contacted the landlord requesting necessary repairs be made in a timely manner," U.S. Postal Service spokesman Philip Bogenberger said via email. "We thank customers for their understanding."

While the trash cans are unsightly and certainly not ideal, Bogenberger said the post office's operations there have not been affected.

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Ingles Markets owns the property. Chief Financial Officer Ron Freeman said they plan to fix the roof "once materials and contractors are available."

"There is currently high demand for the materials and, like many other items, there are disruptions in the supply chain," Freeman said. "We put in a temporary fix a few days ago and hope we can get a new roof put on as soon as possible."

This is the opinion of John Boyle. To submit a question, contact him at 232-5847 or jboyle@citizen-times.com.

This article originally appeared on Asheville Citizen Times: Answer Man: Weather forecasting models? Oteen Post Office a wreck?