Ash Plume May Shift over More of U.K., Germany

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State College, Pa. -- AccuWeather.com meteorologists continue to examine how winds in the upper levels of the atmosphere will be set up between Iceland and Europe over the next few days as an indication to how the ash plume from an Icelandic volcano will behave and affect air travel.

It appears the plume could end up shifting farther south Tuesday into Wednesday, potentially becoming more concentrated over the U.K. and possibly even reaching Germany. Millions of of airline passengers will likely continue facing flight delays and cancellations as a result through midweek.

Forecasting the Position of the Main Ash Plume
Most recent observations as of Sunday have shown the top of the ash plume extending up to 10,000 feet, on average, above the ground. This height has dropped substantially from the 33,000 feet it was at earlier this past week after the volcano first started erupting.

AccuWeather.com meteorologists are looking at the forecast direction and speed of the winds around 10,000 feet above the ground for clues as to where the ash will continue spreading over the next few days.

While looking at the average trajectory of these winds gives a good indication of where the main ash plume will shift, it is impossible to accurately predict where all the ash emitted from the volcano will spread.

Wind speed and direction vary with height and space. Subtle variations in the wind that stray from the average trajectory will cause some of the ash to spread out from the main plume and get carried in different directions.

An example of this is ash that spread out from the main plume and formed a separate cloud over the northern mainland of Europe. This ash cloud can be seen on a satellite image (shown top right) that was captured Friday.

While no new satellite imagery has been available since Friday, images from late last week showed the main plume of ash spanning from Iceland over the northern portion of the U.K. and into southern Scandinavia.

The overall trajectory of the winds at the level of the ash plume are expected to continue steering it from Iceland into the northern U.K. and southern Scandinavia through Monday.

Tuesday into Wednesday, this trajectory is expected to shift farther south, sending any ash emitted by the volcano farther south through the U.K. and into the northern mainland of Europe. Germany and the Netherlands will be at greater risk during this time.

Winds at the level of the ash plume are also expected to become more aligned Tuesday into Wednesday, which may result in the ash plume becoming more concentrated and posing a greater threat to air travel. This of course is assuming the volcano continues to erupt through then.

On a positive note, AccuWeather.com meteorologists expect this greater alignment of the winds to cause the ash plume to become narrower and affect a smaller area.

Details on Separate Ash Cloud that Formed over Europe
Winds across the northern mainland of Europe have been relatively weak the past few days. With a continued lack of strong winds expected there, AccuWeather.com meteorologists anticipate little movement or dissipation through Monday of the separate ash cloud that formed there.

Winds are expected to increase across this area Tuesday into Wednesday, which may help to stir up and clean out the ash cloud currently in place.

Potentially Beneficial Changes Late this Week
The trajectory of the winds at the level of the ash plume are expected to make a dramatic shift toward the end of this week. Instead of being oriented out of the northwest between Iceland and northern Europe, the winds will likely shift to being oriented out of the west-southwest.

This shift should help clean any remaining ash plume out of most of Europe and bring some relief for the aviation crisis, according to AccuWeather.com meteorologists.

Ash Plume's Impacts on Travel
Thousands of flights have been cancelled on a daily basis across Europe since Thursday. According to BBC News, the airspace across approximately 20 countries remained closed Sunday.

The grounding of flights has been in response to the threat ash has on airplane engines and control systems. Volcanic ash is abrasive and can scratch windshields and accumulate in engines, potentially degrading performance to the point of failure.

The virtual shutdown of air travel across Europe is creating nightmares for airline passengers around the world.
Many world leaders were prevented from attending the state funeral in Krakow for Poland's President Lech Kaczynski and his wife Maria.

The Eyjafjallajokull Volcano erupted Tuesday evening (EDT) under a glacier in southern Iceland. Fears of flooding from the melting glacier immediately prompted the evacuation of up to 800 people.

By AccuWeather.com Meteorologists Jim Andrews and Heather Buchman

If you have questions or want to speak to a meteorologist, contact:
Roberti@AccuWeather.com

*Please attribute quotes and images from this News Forecast to AccuWeather.com.

Or call our 24-hour press hotline:
814-235-8710

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AccuWeather.com
Justin Roberti
814-235-8710
Roberti@AccuWeather.com