Meteorologists use many tools to predict the weather. They use past data such as temperature observations, real-time data such as radar and satellite images,
and models that look into the future. Many different parameters are plotted using the numerical forecast models, which are generated using computers. The models consist
of numerical equations which use current conditions as the inputs. The resulting outputs are forecasts for what is likely to happen in the future, based on those initial
conditions. There are many different models that all attempt to do the same thing. The Flow Following Finite Volume Icosahedral Model (FIM) is unique because it uses an
icosahedral grid rather than a grid of the latitude and longitude lines like most weather models. The icosahedral grid is mostly hexagons except for 12 pentagons
(think of a soccer ball).
The moving tracers show the 250mb (millibar) wind trajectories over the preceding 12 hours. These tracks evolve during the model forecast run showing the movement of weather
systems. The growth of each tracer shows the trajectory one would follow if riding in a balloon held at the 250mb pressure level. 250mb means we are located
at about 35000 feet high in the atmosphere, where the air pressure is about 250mb. This level is useful to look at to help tell the direction
and speed that storm systems will move. The core of the jet stream can be seen at this level. Patterns of troughs and ridges which play a huge part in the weather can be seen clearly as the tracers move. Troughs open up towards the poles and
represent areas of stormy weather, especially on the east sides. West sides of troughs (in the mid-latitudes) tend to have colder weather. Ridges are open towards the equator and
represent areas of calmer and warmer weather. This dataset projects out 6 days from the time the model was started. Model updates are available every 24 hours.
The Flow Following Finite Volume Icosahedral Model (FIM) was developed by NOAA to produce weather forecasts. In fact, weather forecasts from the FIM model are available for SOS here.