Nowcasting with the AROME Model: First Results from the High-Resolution AROME Airport

Applications of Research to Operations at Mesoscale (AROME) Airport is the high-resolution version of the French operational numerical weather prediction model AROME. The purpose of AROME Airport is to provide rapidly updated forecasts with a 500-m resolution for nowcasting over an airport and to help with the prediction of wake vortices in order to increase the efficiency of the airport. Here, the model is evaluated for the area around Paris Charles de Gaulle Airport (CDG), France. AROME Airport and other configurations of the AROME model are compared to observations during two 4-week periods, when additional observations are available for the area around CDG (May June 2011 and September October 2012). The root-mean-square error and the bias are calculated for the 2-m temperature, 10-m wind speed, and the vertical distribution of the wind speed using the available measurements. The performance of AROME Airport is compared to the operational configuration of the AROME model both for synoptic hours and in a more realistic setting using the forecasts from AROME Airport starting every hour. It is shown that the forecasts from AROME Airport are an improvement with respect to the operational when comparing runs from all forecast hours, particularly for the wind speed, but when comparing the synoptic hours, the results are less clear. The sensitivity of AROME Airport to its data assimilation and initial and lateral boundary conditions is also discussed.