Numerical Weather Models

There are a tremendous amount of weather model in use around the world today. Most industrialized countries have their own. In the United States, the National Centers for Environmental Prediction (NCEP) is the official government weather modelling center. AFWA runs some models to include the Weater Research and Forecast (WRF) model. Let's take a tour through the NCEP site at http://www.ncep.noaa.gov/  Here is what you will see.

We'll spend the next hour or so navigating the site and looking the the attributes of the weather models in the USA and around the world. The Global Forecast System (GFS) is generally considered the most useful model for forecasts out to 10-days, while the WRF should be considered when a very accurate less than twenty four hour forecast is needed for a specific point or mission. 

VIV process

Weather models are not always correct and it is your students' job to correct them for inaccuracies to be able to adjust and make accurate forecasts. This process can be broken up into three steps of: Verification of previous runs of a model, Initialization of the zero-hour forecast of the current model, and verification of subsequent prognosis charts. In our business this is known as the VIV process.

The VIV process is really a process of trend analysis. You teach your students to verify previous model runs, compare that with the current model's initialization, and then verify the new model. If the model is getting closer to reality as time goes forward, it is ok to use it with little bias. If it is not, teach your students to consider a new model.

The exercise for today is to try this process with a variety of models and see which one is working best. Each group should pick an area of the United States to complete this process. Go the the NWS model site at http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/ to begin this process. We will take about an hour and expect you to brief which model should be considered and why showing your VIV process.