Weather images


Figures 1-4

Figure 1.

The sferics display for 2 and 3 November 2012 (courtesy of the Icelandic Met Office, from the UK’s lightning detection network) illustrates the autumnal preponderance of thundery showers where unstable westerlies have crossed warm seas; coastal convergence (an undisturbed airflow across the sea coming up against a frictionally-disturbed backed flow over land) was also clearly a factor. Jersey Airport recorded thunder on four of the first five days of the month.

Figure 2.

A depression moved northeast over southeast Britain early on 4 November 2012, and a variety of weather was associated with it. The radar image for 0700 utc (courtesy of meteox.co.uk) captures its area of heavy rain (rates up to 10mmh−1). There was isolated thunder, on its western edge an unseasonably early snowfall affected parts of the West Country, and strong winds blew in its wake. Meanwhile, fog persisted for much of the day in parts of northern England and east Wales.

Figure 3.

The floods of the last few days of November were a major news story. Rainfall totals were certainly excessive in parts of the country, but the event drew attention again to aspects of land use and abuse, such as building on flood plains. A typical radar image is that for 1700 utc on 22 November (courtesy of meteox.co.uk). Rainfall rates in the narrow ribbon (cold front) from the western English Channel to the western Midlands exceeded 10mmh−1 and it was also very windy.

Figure 4.

This infrared satellite image (courtesy University of Dundee) for 1043 utc on 25 November picks out the rather unusual incidence of two deep depressions within about 500 miles of each other. The one in the North Sea had given most places a very wet night, with strong winds on its southwestern flank; the one off southwest Ireland was poised to bring another soaking to much of the country. Away from the influence of either, there was persistent freezing fog over parts of Northern Ireland.

Ancillary