Forming on December 31, 2011 off the coast of New Jersey, Ulli began a rapid strengthening phase on January 2 as it sped across the Atlantic.

The storm clustering began in late-November when Xaver and Yoda hit the United Kingdom and Norway.

[16] The storm then made landfall on Scotland during the early morning the same day with a central pressure of 952 mb (28.1 inHg).

[20] In the late hours of January 1, Met Éireann issued a national severe weather warning for Connacht and Ulster and forecasters predicting winds speeds up to 87 mph with heavy driving rain.

On January 2, the Met Office issued an amber weather warning for most of Scotland for heavy snow and strong winds.

[citation needed] On January 3, the Kingston, Erskine, Tay and Forth bridges were closed due to high winds.

[7][26][27] The storm hit Scotland during a public holiday[28] which helped reduced the number of people travelling about.

[32] A tornado, which uprooted trees and damaged roofs, touched down in Hainault, London later in the day.

[41][42] The Dutch Coastguard reported a meteotsunami at IJmuiden on January 3 with sea level rising and falling 1.5 m (4.9 ft) in just 30 minutes as the storm passed.

[20] In Germany on January 3, a storm warning was issued for the North Sea coast and higher altitudes.

[44] Coastal regions were also battered by large waves with ferry passengers having to walk through flood water to disembark.

[50] The storm continued across the Kattegat to affect the Swedish west coast with power outages, blocked roads and cancellation of train services.

[51] Forecasters began to predict another storm that would make its way across the North Sea in the coming days, which had already named Andrea.