Circulation in June 2019

The heatwave over parts of France may have caught all the headlines but the centre of the warmth in June lay much further east in Poland and Ukraine.

1912 the most cyclonic June

This June has already started on a very cyclonic note, and interestingly there are already five June’s from this century already in the top twelve, with June 2012 ranked as second highest.

A new way of looking at weather charts

The valuable chart archives on the Wetterzentrale site provides a number of reanalysis series, from CFSR, ERA and NOAA that you can download daily charts from. The CFSR series is at 0.5° resolution, whilst data from ERA is 1° and NOAA 2° resolution. Here’s an example of all the daily charts (00 UTC) for last winter [DJF 2018-19] using CFSR reanalysis data of MSLP and geopotential height at 500 hPa. Trying to find the start and end of any cold or warm spell in a series of weather charts by quantifying just how cold or warm it’s been in any...

May 1896 most anticyclonic

Looking at the Jenkinson Lamb objective weather data from the CRU at the UEA, I find that May 1896 was the most anticyclonic across the British isles in the record that started in 1871. I’ve gauged this on the combined frequency of the daily anticyclonic or hybrid anticyclonic LWT. May 1896 scores an extremely high 74% anticyclonic for the whole month, which is way ahead of the next year in the list, 1871 with 63%. My findings are backed up by the weather charts for the month based on the American reanalysis data. This May is already off to a...