Quantitative precipitation forecast

[1] A QPF will be created when precipitation amounts reaching a minimum threshold are expected during the forecast's valid period.

Terrain is considered in QPFs by use of topography or based upon climatological precipitation patterns from observations with fine detail.

Starting in the mid-to-late 1990s, QPFs were used within hydrologic forecast models to simulate impact to rivers throughout the United States.

The forecasts can be verified through use of rain gauge measurements, weather radar estimates, or a combination of both.

Algorithms exist to forecast rainfall based on short term radar trends, within a matter of hours.

[8] Professionals are required to interpret the model data into weather forecasts that are understandable to the lay person.

Professionals can use knowledge of local effects which may be too small in size to be resolved by the model to add information to the forecast.

As an example, terrain is considered in the QPF process by using topography or climatological precipitation patterns from observations with fine detail.

[13] However, there are now expert systems using those data and mesoscale numerical model to make better extrapolation, including evolution of those features in time.

There comes a point when the errors are so large that the forecast has no correlation with the actual state of the atmosphere.

Starting in the mid-to-late 1990s, QPFs were used within hydrologic forecast models to simulate impact of rainfall on river stages.

Weather radar estimates can be used outright, or corrected for rain gauge observations.