We investigate the plasma flows resulting from the interaction between a mature active region (AR) and a surrounding equatorial coronal hole (CH) observed by Hinode's EIS and XRT from 15 to 18 October 2007. For 3 days, EIS velocity maps showed upflows at the AR's eastern and western edges that were consistently between 5 and 10 km s~(-1), whereas downflows of up to 30 km s~(-1) were seen in AR loops. However, on 18 October, velocity profiles of hotter coronal lines revealed intensification in upflow velocities of up to 18 km s~(-1) at the AR's western footpoints 4.5 hours prior to a CME. We compare the AR's plasma flows with 2.5D MHD numerical simulations of the magnetic configuration, which show that expansion of the mature AR's loops drives upflows along the neighboring CH field. Further, the intensification of upflows observed on the AR's western side prior to a CME is interpreted to he the result of the expansion of a flux rope containing a filament further compressing the neighboring CH field.
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