R - University of Wisconsin MM5 Real Time Forecast and Forecast ...

Impact studies or “what if?” experiments• Impact studies involve studying the effects a specificinitial and/or boundary perturbation (x 0 ) to an NWPmodel has on some aspect of a forecast.• While these perturbations are often chosen based on“synoptic intuition”, typically the precise choice of thelocation and structure of the imposed initialperturbations is not known.• The chosen perturbations may have very little impacton the weather system of interest.• As these studies are performed to assess theimportance of a particular synoptic feature, manyintegrations are needed to yield useful results.