Tag Archives: FV3-GFS

THE FV3-GFS WEATHER MODEL

Today, with its morning model run, the National Center for Environmental Prediction (NCEP) will have upgraded the GFS model (version 14) to the new and improved FV3-GFS (GFS version 15.1.1). The FV3-GFS becomes the main global model of the National Weather Service today.

The FV3-GFS (Finite Volume Cubed Sphere) has been in development for well over 10 years and has been in testing for the past three. It uses a different three dimensional geometry to reduce errors inherent in all numeric weather models. It includes different modeling physics and new parameters.   Significant information on the FV3-GFS can be found here.  Background information is here.

The model data has been available on university web sites in a very limited fashion for awhile.  Over the past two weeks, the NCEP made the data available on the main weather model download server, “NOMADS”.

The FV3-GFS has been heavily evaluated and is considered “equal or better” than the current GFS.

WEEKEND WEATHER FORECAST

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This weekend’s weather will be the nicest we’ve had in many weeks and the forecast  will be easier as well —  a  far cry from the boundary conditions with a stalled front  we’ve had to deal with over past weekends.

Both Saturday and Sunday will be sunny.  High on Saturday 84 and high on Sunday 90!

Sat AM Update: High temperatures have shifted a bit higher for Saturday 86 and Sunday 91.

We’re finally entering a summer-like weather stretch. Monday’s high is expected to be 96-98 with increasing dew points.


By the way, the NWS announced today an expected major update in the GFS model. The new GFS model, to be referred to as the FV3-GFS,  will become operational in mid January 2019, in time to improve snow forecasts.

From what I could infer from reading about the new model, its improvement is in part due to changes in the geometry of how the globe’s atmosphere  is broken down into a 3 dimensional mathematical grid.

The new geometry, a Finite Volume Cubed Sphere, (hence FV3) allows for better computation at the edges of each cubed grid, and reduces approximations where some of the physics would ordinarily result in infinite mathematical series or unsolvable equations.  This should result in better forecasts .

The pre-release version of this new model was used for this forecast’s high temperatures. We’ll see if the highs on Monday really reach 96+.