An in-situ observation based study recently found decreasing storm spatial extent with increasing temperatures for 1-hr duration precipitation events in the Greater Sydney region. Here we present an assessment of a regional climate model's ability to capture this characteristics. Multiple regional climate models were considered: the first a convection-resolving simulation at 2-km resolution, the rest at a resolution of 10 km with three different convection parameterizations. Both the 2- and the 10-km resolutions that used the Betts-Miller-Janjic convective scheme simulate decreasing storm spatial extent with increasing temperatures for 1-hr duration precipitation events, consistent with the observation-based. However, other observed relationships of extreme rainfall with increasing temperature were not well represented by the models. Improved methods for considering storm organization are required to better understand potential future changes.