Wednesday, September 26, 2012

Rainy Pattern In UK With More Flooding

One of the stories in the run up to the Olympics in London was the heavy rains that had fallen in June and early July throughout the UK.  That pattern has resurrected itself with another dousing of rain as a stubborn trough has set up shop across Western Europe.  Parts of the UK picked up nearly three inches of rain in a 48 hour stretch earlier this week, with another inch or two of rain expected today in some localized downpours.  Some have considered this the worst September storm system to move through the UK since 1981.

The cause of the rainy pattern has been an anomalous trough in Western Europe that has been slow to move since the initial storm system moved into the UK and Ireland on Sunday.  This system ingested some of the moisture from Nadine, which was situated near the Azores Islands (west of Portugal and Spain towards the center left of the map) at the time but did not fully ingest tropical system as a whole.  Nadine still exists and is meandering around to the south of the Azores.  The trough slowly intensified as it fed off of a combination of Nadine's energy and a buckling jet stream.  The pattern, stuck and relatively slow moving, will take until the weekend to fully break down as the upper trough slowly weakens over the UK and the strong ridge in place in North Atlantic begins to nudge the weakening trough along.  It doesn't help that a ridge of high pressure has bubbled and blocked in place over Eastern Europe, creating a relatively large and unusual roadblock in the pattern aloft.

More flooding in parts of the UK is possible, especially on Friday with another storm system poised to move in from the west (you can see it near Iceland on the satellite).