Aircraft condensation trails, also known as contrails, have a significant impact on the global climate when they persist. In this work, we present a modification to the Météo-France weather model ARPEGE (Action de Recherche Petite Echelle Grande Echelle) to improve the forecasting of areas favourable to the persistence of contrails. The spatial correspondence between observations and the modified model is demonstrated and evaluated by appropriate metrics. The modified model can therefore be used for further contrail climate impact applications.