Wednesday, 2 March 2016

A winter of extremes in Britain

Gale After Gale After Gale Dumped Two and a Half Feet of Rain Upon Scotland and Wales This Winter

1 March, 2016

Reports from the UK Met Office are in. And we can say now with confidence that the UK have never seen weather like what they experienced this Winter. It looks like a storm track super-charged by climate change really socked it to the region this year. That we’ve just passed a winter worse than the then record years of 2013 and 2014 — only two years on.

A Stormy New Climate State for the North Atlantic

For the UK and for North Atlantic weather stability in general, the sea surface temperature anomaly signature in the graphic below is bad news. The cool pool just south of Greenland (indicated by the swatch of pale blue) is a new climate feature. One that appears to be related to glacial ice melt outflow from Greenland.

North Atlantic Sea Surface Temperatures
(10 degree Celsius above average sea surface temperatures off North America in today’s ensemble sea surface temperature model graphic are just insanely warm. Ocean surface anomalies used to rarely exceed 2 degrees Celsius warmer than average. These spikes off North America are an indication that the Gulf Stream is backing up and that overturning circulation off Greenland is slowing down. Image source: RTG-SST/NCEP /US National Weather Service/Earth Nullschool.)

Such melt outflow tends to slightly freshen sea surface waters. Freshening waters keep more heat locked into the ocean’s depths. They tend to cool the surface waters. And they slow down an ocean overturning circulation that, in the North Atlantic, drives the flow of the Gulf Stream.
A slowing Gulf Stream delivers less heat to this zone even as it piles more heat up off the North American Coast. As a result, a warm west, cool east dipole tends to develop. In the cool region south of Greenland, unusually strong storms have developed more and more frequently — with a dramatic impact on UK weather. The storms feed on this temperature differential even as they have gorged on heat and moisture streaming northward in a meridional flow over Western Europe. The results this year were nothing short of record-shattering.
Hottest and Wettest

For England and Wales, with temperatures ranging about 2 degrees Celsius above average for December, January and February, 2015-2016 probably beat out 2007 and 1989 as the hottest Winter on record. Meanwhile, Wales and Scotland saw the most rainfall ever recorded — with totals for both regions hitting around 756 millimeters or about two and one half feet. That’s even more rainfall than the previous record stormy Winter of 2013 and 2014.

Yet one more Gale
(Yet one more gale sets up to hammer Ireland, the UK and Scotland by Thursday. Four months of ongoing stormy conditions appears set to continue through to at least mid-March. Image source: NOAA’s Ocean Prediction Center.)

These heavy rains set off severe floods and damaged homes, roads, and bridges throughout the UK with the worst damage focusing in on regions to the North. One heavy precipitation hot spot — Argyll — saw an extraordinary 1035 mm or 3.5 feet of rainfall over the three month period. The Met Office is quick to point out that though December, January and February were the wettest on record since 1910, heavy rainfall events began in November — resulting in what amounts to a relentless four month pounding as storm followed storm and flood followed flood.

And, it appears, this persistent and ongoing storm pattern has not yet changed. For the North Atlantic remains riled — setting up to hurl a new gale-force low at Ireland and the UK this week. With the weather pattern essentially stuck in stormy since November, folks from these regions have got to be asking — when’s it going to end? As storms continue to fire off in the dipole zone above, it appears it will likely last until at least mid-March.
Hat tip to Colorado Bob
Hat tip to TodaysGuestIs
Hat tip to Dan Combs

No comments:

Post a Comment