The Spanish Plume is a weather pattern in which a plume of warm air moves from the Iberian plateau or the Sahara to northwest Europe giving rise to severe thunderstorms. This meteorological pattern can lead to extreme high temperatures and intense rainfall during the summer months, with potential for flash flooding, damaging hail storms, and tornado formation. Some of these intense thunderstorms are formed from thermal lows. Thermal lows are also known as heat lows. Thermal lows can be semipermanent features around some parts of Europe, particularly in the summer season. These thermal lows can be developed or created around Spain, Portugal, France etc., during the summer season because of the intense heat. Thermal low pressure can be located around the world, particularly in the summer or in tropical regions.
Notable occurrences
1788, 13 July, a hailstorm sweeps across France and the Dutch Republic with hailstones 'as big as quart bottles' that take 'three days to melt'; immense damage is done.
1955, 18 July a Spanish Plume brought a record amount of rain on one day to Martinstown Dorset, with slow-moving thunderstorms bringing 279mm of rainfall. A record which stood for over 50 years until the 2009 Cumbria floods.
1958, 5 September Horsham storm, heaviest hailstone recorded in the UK.
1959, 9 July Wokingham storm. the first in the world to be identified as a supercell.
1961, 12 August synoptic set-up of a Spanish Plume, however dry ground conditions in France led to little evaporation which led to lack of moisture in the air to fuel cloud and storm formation.
2013, 26–27 July A Mesoscale convective system developed in France and moved across the Netherlands and northern Germany, a gust of 102 mph was recorded at Pauillac, France from the storm. Smaller scale thunderstorms developed in the UK.
2014, 17–21 July severe storms left at least two fatalities in France, with power cut to thousands of homes and localised flooding occurring in France and the United Kingdom.
2015, 30 June–4 July A plume brought high temperatures from Spain across France and the UK. In France some July temperature records were set, and in the UK some all time maxima were set in some locations. Severe thunderstorms also moved northwards across the UK on 1 July and again overnight 3–4 July.
A similar pattern, though on a larger scale, is the Mexican plume in the south west USA, where hot dry air from the Mexican highlands acts as a cap to convection until lifted over Texas, Arkansas and Oklahoma.
Eastern Baltic
In Finland and the Baltic states meteorologists have observed a situation conducive to severe summer storm development which occurs when a warm moist air mass flows into the region from the south or south east under the influence of an upper-level trough. These conditions have some similarities to the Spanish plume. The synoptic conditions see a low over southern Norway, bringing warm south and southwesterly flows of air up from the inner continental areas of Russia and Belarus.
