In the last few days, SSE winds triggered by unusually strong low pressure west of Iberia and high pressure over Italy as picked up and forced a cloud of Saharan dust to travel over 2,000 miles within the mid and upper levels of the atmosphere, bringing a surprise but not particularly unusual fine layer of dust to cars across parts of the UK.

TOP IMAGE: Courtesy of NASA

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This air flow has managed to cross and collect other properties on it’s way north, the other properties being, highly polluted air from the big industrial centres over mainly France but Spain and Belgium as well and so now that this air mass is floating over Britain, so the combination of dust particles and air pollution from neighbouring industrial nations to the south, has raised the Central and Southern UK pollution levels to VERY HIGH, mainly over London, East Anglia and East Midlands.

Check out the dust on this car in London yesterday.

Saharan dust floating within our airspace tends to produce glorious sunsets. Check out this great shot of the setting sun last night over London. Captured by Simon Cardy.

The dust is simply making the situation worse but it’s the warm sunshine which helps thicken smog/ground level ozone near the surface throughout the course of the day as home grown pollution builds. The worst part of the day will likely be rush hour this evening.

This 00hrs 10m wind barb chart shows the air flow extending from Africa to the UK and as it does so, it’s crossing the industrial heart of France including the city of Paris.

This jet stream chart shows the big dip with the upper trough extending from Greenland to nearly as far south as the Canaries. The other upper trough extends from the arctic to as far south as the eastern Med.

In between these trough, a multi layer S to SE air flow is generated, pulling air/dust from the heart of Algeria and Libya northward. Warm air is less dense than cold, so dust and dirty air is suspended easily. This setup has allowed the UK to witness the warmest day of 2014 with a high of at least 21C in Frittenden, Kent. In contrast, Madrid is only ‘warming’ to the mid teens.

View from 500mb at 12 hrs.

Current surface off ECMWF.

Cloud/Rain To Temper Pollution Levels Tomorrow, Atlantic Winds To Push Dirt Out By Friday!

Increased cloud and rain tomorrow should at least temper air pollution levels in the South and Midlands of England tomorrow but by Friday winds turn SW and this should kick out this dirty air out into the North Sea.

Here’s the surface chart through 12z tomorrow. Notice little real change except more cloud and rain may help LOWER pollution levels. Notice the continued wet conditions down across Spain and Portugal.

By 66 hrs the Iberian low pushes east, breaking down the ridging over the Med and ultimately the trough takes over Western Europe including the UK once again. Winds start to turn SW and thus cleaning out the UK atmosphere.

96 hrs

By late weekend, the pattern is very much Atlantic dominated again with a flatter SW to NE flow across much of Europe but a big, chilly cut off low will keep things cool over the Balkans, Turkey down into the eastern Med where showers will be frequent. Pressures build back west over the western Med and Iberia.

Next week is looking much cooler and more unsettled from Ireland across the UK and into Western mainland Europe. Note the low thicknesses over the UK which will make for a chilly, showery, blustery regime in the below surface at 156 hrs.

The NAO is poised to go firmly positive along with the AO once again and if so, the ECMWF may be onto something for late next week with building heights from Iberia northwards into the UK.

240 hr surface

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Tags: air pollution, sahara dust