One of the big stories you've been hearing/reading about over the past few days has been the ongoing eruption of an Icelandic volcano and the volcanic debris that's been lofted hundreds of miles downwind of Iceland.. volcanic ash that has virtually paralyzed air travel across northern Europe. The prevailing wind pattern in the northern hemisphere is westerly, with variations between northwest and southwest depending on the orientation of areas of high and low pressure. Right now, there is a skinny, but strong area of high pressure aloft to the west of the United Kingdom in the northeast Atlantic Ocean, a feature we call a thumb ridge. This is creating north to north-northwesterly wind blowing the volcanic ash directly toward some of the busiest terminals in the world, such as London Heathrow.
This pattern is expected to relax later this week as that "thumb ridge" moves toward the UK. As this happens, the volanic ash will likely be sent more in the direction of Germany, Poland and western Russia perhaps allowing air travel to return close to normal in western Europe by the middle of the week. Into the weekend, the pattern is expected to remain far more favorable for stranded travelers in Europe as more of a westerly flow develops over northern Europe.. this would carry any remaining ash toward Scandanaiva (Sweden/Norway). Of course, the wild card here is whether eruptions will continue on Iceland.. if they do, travelers will continue to be at the mercy of the shifting wind in the upper levels of the atmosphere!
Brian
