Figure 4. Sea Surface Temperatures (SSTs) near Malta are about 23°C (73°F), which is warm enough to support a subtropical storm, but probably not a tropical storm. Ocean temperatures are cooler on the east side of Sicily, about 21°C (70°F.) The coldest waters I've seen an Atlantic tropical storm form in were 22°C during Hurricane Epsilon of 2005. Cool air aloft can offset cold SSTs and create the instability needed to create a Medicane.