Category Archives: Commentary

SO WHAT HAPPENED TO THE STORMS?

So what happened to the storms and flash flooding expected for today?

Clearly, the models didn’t do a very good job here.  On Sunday, the models overwhelming predicted a severe weather event.  They continued to do this on Monday, but by Monday evening there was a lack of agreement, with some models showing the insignificant showers we ended up with.

By this morning, the severe weather parameters had become very unimpressive and I posted that change this morning.  Still, the Rapid Refresh model (RAP) available at 9:35 AM showed a line of storms about 4 PM.

While at work, the rest of this morning’s models became available between 10:15 and 12:40.   The NAM NEST, WRF-AWF, WRF-NMMB, RAP, HRRR and HRDPS are the models I look at for thunderstorms. (Hey, it’s almost a full-time job, but it’s still a hobby.)

By this morning’s model run, the models had really backed off considerably with even the rain, shunting anything developing to our south.   Too late to make an updated web announcement, while at work.

Interestingly, they were still talking about severe thunderstorms on the radio while driving home at 6:30 PM.

It’s always a tough call to cancel the call for severe weather when even the slight possibility could endanger people if it occurs.

Anyhow, the “elusive” search for the model that’s always correct is elusive for a reason.

Looking back, even the GFS, a large-scale model, did better yesterday than some of the high resolution models.  And if I had to hang my hat on a model yesterday, the Canadian HRDPS probably called it the best at the earliest time.  But it’s not always right…

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.