North Atlantic Oscillation (NAO) Forecast - from the NOAA CDC

The NAO is measured as the pressure differential between the Azores and Iceland. A negative NAO often indicates colder than average weather for western europe during the winter months. A positive NAO during the winter often indicates unsettled and milder weather.

The latest forecast is available here:
North Atlantic Oscillation (NAO) Forecast - from the NOAA CDC