ICON-2I, Italy's 2 km model over its seas

Italy's seas are a maze of islands, straits and mountains dropping into the water. The Strait of Bonifacio accelerates whatever blows, the bora pours down the Adriatic's eastern coast in gusts, the scirocco builds up the length of the Tyrrhenian. Around the south of Sicily, Malta and the Ionian Sea, a sailor had only models of 6 km or more, which draw a strait as a few cells of open water.

ICON-2I, run by Italy's national weather service, ItaliaMeteo, is the German ICON model at 2.2 km over Italy and its seas: it computes showers and thunderstorms itself, and starts every run from the latest observations, the Italian weather radars among them. Saily WR reads its two runs a day, hour by hour up to 72 hours, three days ahead.

Its area runs from Menorca to the west of Greece and from the Alps to Tunisia and Malta: Corsica and Sardinia, the Tyrrhenian Sea, Sicily, the whole Adriatic and the Ionian Sea as far as Zakynthos. Over the Gulf of Lion, Corsica, Sardinia and the Adriatic it is one more fine opinion beside AROME, ICON-D2 and HARMONIE DINI; around Malta and the south of Sicily it is the only one.

From Siracusa to Malta, a night's crossing of some eighty miles, ICON-2I is the only fine model on the water. It sees how the south-east corner of Sicily and Capo Passero bend the wind, which the global models smooth away: when its route parts from theirs near the cape, it is the one to weigh first. Further out, where nothing bends the wind, they agree more often, and their agreement is worth as much as its detail.

Its three days suit coastal passages and crossings: Corsica to the mainland, the Strait of Bonifacio, the Adriatic. Beyond them, the global models take over. The large weather systems come into it from ECMWF at its edges, so it does not judge them independently. Few of its observations are made at sea, where its starting point rests largely on its own previous forecast; a thunderstorm in its forecast is a warning, not a schedule.