Zeer sterk meriodinaal ontwikkeld hoogtepatroon
Bericht van: Saskia (Diepenveen) - moderator - , 22-03-2012 09:03Why the record early-season warmth?
The unusual warmth is due to a loop in the jet stream that has created a large upper-level ridge of high pressure that is stuck in place over the Eastern U.S.--a phenomenon known as a "blocking pattern." Since the jet stream acts as the boundary between cold air to the north and warm air to the south, and the large loop in the jet places its axis far to the north of the eastern U.S., summer-like warmth has developed over the eastern half of the U.S. Conversely, colder than average temperatures have developed over the western third of the U.S. behind the southwards-dipping loop of the jet stream. This jet stream pattern is too extreme to be stable, and the big loop over the Western U.S. will break off and form a giant eddy on Wednesday. The resulting area of low pressure will be known as a "cut-off low", because it will be cut off from the jet stream. The cut-off low will drift slowly eastwards during the week, gradually bringing an end to "Summer in March" over the Eastern half of the U.S.
Jeff Masters
Bron: Dr. Jeff Masters' WunderBlog - Torrential rains in Oklahoma; Summer in March continues for Midwest
Bericht laatst bijgewerkt: 22-03-2012 11:36
