The models have really shifted since I opened up this thread just two days ago. A change to much cooler and very unsettled conditions was always on the cards from the 5th but this has now firmed up and been accentuated in the latest output. So much so that by the 13th the CET may now only be 0.3C above the 1971-2000 mean (entirely due to the first few days) and actually slightly below the 1981-2010 mean.
These sudden shifts from benign and warm late summer to full on Autumn are not unusual. For example this year is taking a very similar path to 2004. In that year September saw a CET of 14.9C which is basically the same as we have had this year. The last day of September closed on a CET of 15.3C. It was also a fairly dry month, although not as dry as this year, with 50mm on the EWP which is well below the mean of 78mm.
October 2004 opened up with a CET of 11.1C and remained at around 11-12C for the first few days. Then between the 7th and the 21st the CET was frequently in single figures with a few days nudging above 10C. It was also wet. The 3rd saw over 22mm on the EWP although much of the first 12 days saw relatively small amounts of rain. But from the 13th onward it was very wet. In broad terms I sense something similar shaping up for 2014.
