DISCUSSION: As a strong low pressure system stalled out across the central Mediterranean over the past few days, the stage was set for a persistent surge of deep, tropical moisture into this part of the Mediterranean. As a result of this persistent moisture advection, the aforementioned low pressure system has plenty of moisture to work with as far as generating precipitation was concerned. As you can see in the footage above (courtesy of Manoel Bajada), the flooding was extraordinary and likely unprecedented for that part of the Mediterranean. It is also worth noting that the presence of higher terrain in and around several cities within Malta helped to facilitate a classic orographic enhancement of precipitation.
Orographic enhancement of precipitation occurs when incoming air parcels are forced to rise up and over a given slope or mountain. As a result of these air parcels being forced over this steeper terrain, they are forced up into a colder environment (at a higher altitude) and therefore are forced to expand and become increasingly more unstable. During this process of parcel expansion, a given air parcel will release close to (if not exactly) it's maximum moisture content for a lengthier period of time. Thus, orographic enhancement is consistently found to generate locally higher precipitation totals all over the world (i.e., both in winter as well as summer-time events).
Despite being positioned in a region which climatologically receives a large amount of annual rainfall during a typical year, this was still a more anomalous event which had profound impacts on regional travel and infrastructure across the island nation of Malta. As continually iterated by staff all across the National Weather Service network back over in the contiguous United States, when and if you approach flooded roadways, always be sure to "Turn Around and Don't Drown."
To learn more about other high-impact weather events from across Europe, be sure to click here!
~Meteorologist Jordan Rabinowitz