The newest NOAA: ”Arctic Report Card: Update for 2010” mention a phenomenal wind change that happened previously only three times before in the last 160 years, without mentioning the years. One winter was definitely the 1st war winter in WWII, 1939/40. There was for example a wind shift in Great Britain (see Fig. right). The temperature maps, than and now, prove a high similarity.
R. Scherhag explained the sudden change 1939/40 a few years later in this way: