The Weather Service prepares to launch prediction model that many forecasters don’t trust

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On Dec. 4, the FV3 model from the National Weather Service predicted a major snowstorm for Washington five days later. The storm missed the city. It is slated to become the Weather Service’s flagship model in March. (TropicalTidBits.com)
February 14

In a month, the National Weather Service plans to launch its “next generation” weather prediction model with the aim of “better, more timely forecasts.” But many meteorologists familiar with the model fear it is unreliable.

The introduction of a model that forecasters lack confidence in matters, considering the enormous impact that weather has on the economy, valued at around $485 billion annually.

The Weather Service announced Wednesday that the model, known as the GFS-FV3 (FV3 stands for Finite­ Volume Cubed-Sphere dynamical core), is “tentatively” set to become the United States’ primary forecast model on March 20, pending tests. It is an update to the current version of the GFS (Global Forecast System), popularly known as the American model, which has existed in various forms for more than 30 years.

The introduction of the FV3 is intended as the Weather Service’s next step toward building the best weather prediction model in the world, a stated priority of the Trump administration. The current GFS model trails the European model in accuracy, and it has for many years, despite millions of dollars in congressional funding dating back to 2012, after Hurricane Sandy hit.

Numerous meteorologists who have experience using the FV3 worry it’s not ready for prime time and have been underwhelmed by its performance. For months, its predictions have been publicly available, on an experimental basis for forecasters to evaluate.

When news broke about the Weather Service’s intention to make the FV3 the United States’ primary model, meteorologists unleashed a torrent of complaints and negative reviews on Twitter.

“It has not been good at all,” tweeted Doug Kammerer, chief meteorologist for NBC4 in Washington. “Scary that this is what we are about to go with on a permanent basis.”

“From what I have seen . . . not impressed,” tweeted Ryan Hanrahan, chief meteorologist for the NBC affiliate Hartford.

“I have no faith in the FV3 [for snowfall forecasts].” tweeted Judah Cohen, a meteorologist at Atmospheric Environmental Research known for his long-range prediction of the polar vortex.

Mike Smith, who recently retired as a senior vice president at AccuWeather, said the FV3 is not an improvement over the model it will replace. “I don’t see any way in which FV3 provides better weather forecasts versus the current GFS,” he tweeted.

The model has tended to overpredict snowfall in the heavily populated Interstate 95 corridor in the Mid-Atlantic and Northeast, setting off false alarms in a region where forecasts are particularly consequential.

In Boston, which has seen just six inches of snow this winter, Eric Fisher, chief meteorologist for the CBS affiliate, remarked that the model had predicted “multiple” 30-inch snowfalls.

Here in Washington, we have documented multiple cases in which its snowfall forecasts several days into the future have been erroneously high. In early December, it was predicting double-digit amounts for Washington four days before a storm tracked to the south and no snow fell.

On Monday, the FV3 was predicting double-digit totals for a storm on Saturday in the Washington region, and it now calls for little snow.


FV3 model snow forecast for Mid-Atlantic and Northeast through Saturday issued on Tuesday. It predicted over 10 inches for Washington, and current forecasts are now for little or no accumulation. (TropicalTidBits.com)

Cliff Mass, a professor of atmospheric sciences at the University of Washington, has traced the problems in its snowfall forecasts to predicting temperatures “far too cold in the lower atmosphere” more than a few days into the future.

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