Here, we can see a cold air outbreak in this GOES-13 animation, using visible (day) and near-IR (night). This particular event shows offshore flow emerging from the NE US and Eastern Canada on the 6th March. The cold air floods over almost the entire North Atlantic region, eventually passing over the Azores (ARM ENA site, 39N, 28W) on the 8th March. The cold air outbreak is mared by open cellular convection in the low clouds. During the time that the cold air outbreak is over the Azores, the concentration of cloud condensation nuclei drops to lower than 50 /cm3, after the precipitation associated with the low clouds removes particles by coalescence scavenging. The event can also be seen on NASA Worldview.