Nowcasting

Nowcasting performs advection calculations on motions data from radar products to predict weather movement and severity in the near future.

The default time scale for nowcasting is 2 hours into the future. The time scale is configurable between 1 to 6 hours, but high values are not recommended as the forecast gets less reliable as the time goes on.

In this time range IRIS Focus can predict smaller features such as individual showers and thunderstorms with reasonable accuracy using image advection techniques. As part of the techniques, nowcasting extrapolates storm (echo) motion n hours into the future.

Nowcasting does not attempt to imply laws of physics into the model, such as performed in numerical weather prediction (NWP). By using advection extrapolation instead of NWP, nowcasting can include details that cannot be solved by NWP models running over longer forecast periods.

Nowcasting can be used by, for example, road, energy, or airport organizations to provide real-time decision making support.

IRIS Focus nowcasting uses an area-based method in which a motion vector field (MVF) is estimated over the entire observed area to provide insight into many types of precipitation. The IRIS Focus display advects cartesian products into the future.

You can view nowcasted data in IRIS Focus by moving the slider on the animation timeline. When you are in nowcasting mode, the appearance of the timestamps change to indicate that you are viewing nowcasted data.