Last week the Met Office issued their Final Briefing of the recent storms. The report is good in parts and down right ugly in others.
The report says this:
As yet, there is no definitive answer on the possible contribution of climate change [manmade] to the recent storminess, rainfall amounts and the consequent flooding. This is in part due to the highly variable nature of UK weather and climate.
So the official line is that it is not possible to link the storms to manmade global warming and it is good to get that controversial point cleared up. There are two serious omissions from the whole report 1) heavy snow fall in Scotland is not mentioned once and 2) the role of flood management in causing flooding is not mentioned. And exceptional high tides that are discussed in the main report are omitted from the summary. Including these data in the synopsis drives thinking about these storms quite firmly away from manmade towards natural causes (and vice versa). The main manmade contribution is locally inept flood management.
This post is based around the report summary where each paragraph is dissected and compared with reality and the main report. The Met Office summary in blockquotesbelow, my commentary in normal text.
Figure 1 Map from the Met Office showing rainfall distribution in December 2013 and January 2014. Scotland was exceptionally wet in December which is mentioned only once. Parts of England were dry in December as was northern Scotland in January. These short time scale regional variations are normally put down to weather.
This winter the UK has been affected very severely by an exceptional run of winter storms, culminating in serious coastal damage and widespread, persistent flooding.
In fact it is mainly southern England and NE Scotland that has been affected according to the Met Office map (Figure 1). Northern Scotland has been much drier than what we consider to be normal.
This period of weather has been part of major perturbations to the Pacific and North Atlantic jet streams driven, in part, by persistent rainfall over Indonesia and the tropical West Pacific.
It is beyond my understanding how they can attribute rainfall to reconfiguring the Pacific jet stream. Surely it is a change in the jet stream track that has caused persistent rainfall in Indonesia?