View Full Version : Jet Stream heads south - UK floods

Jan Klimkowski
07-06-2012, 10:16 PM
Well well well....

The article is from June 20, but parts of the UK are currently flooded as a month's rain falls in 24 hours. Again.

And the Jet Stream is still way south of where it should be and the key factor in these summer monsoons and periods of prolonged extreme weather (of one type or another)....

Nothing to see here....

Blame the jet stream for return of heavy rain

Paul Hudson (http://www.bbc.co.uk/blogs/paulhudson/2012/06/blame-the-jet-stream-for-retur.shtml) | 15:28 UK time, Wednesday, 20 June 2012

After a short spell of fine and warm weather in the last few days, Atlantic weather fronts are once again expected to spread wind and rain across the country tonight and tomorrow, leading us into a fourth successive weekend washout.

According to Philip Eden, writing in the Sunday Telegraph, the first half of June across the UK was the wettest for 150 years - and let's not forget April was the wettest on record too.

The weather pattern is so stuck in a rut that there's every chance that low pressure will dominate our weather for the rest of June and into the first half of July too - meaning more cool and at times wet weather - with a few fine warm days in-between.

And it's all down to the position of the jet stream.

The jet stream is a fast moving zone of winds high up in the atmosphere, caused by the temperature contrast between cold air to the north, and warmer air to the south.
It's along this boundary, where warm and cold air constantly battle each other, that most of our rain bearing weather systems form.

And the jet stream, for some time now, has been further south than normal - hence the inclement weather.

Looking back through the climate records for the last few years it's striking just how polarised our weather has become, with one particular type of weather lasting for weeks on-end.

So far this year March was one of the warmest and sunniest on record; April the wettest on record; now the first half of June is the wettest for 150 years.

This followed the driest 24 months since records began; and let's not forget April last year was the warmest on record which followed the coldest & snowiest December since 1890, during the coldest winter for over 30 years.

This pattern of extreme weather swings in the last few years seems to be getting more common.

Recent research published in Nature offers a possible explanation as to why this seems to be the case, suggesting that the unusual behaviour of the jet stream could be linked to warming that has been observed in the Arctic.

The research shows that because the jet stream is a function of the temperature contrast above the Atlantic, if that contrast is reduced because higher latitudes are warmer than normal, then the jet stream would weaken.

This would effectively slow its eastwards propagation. And one of the consequences would be that a particular type of weather may persist for longer.

Arctic warming may also be causing the jet stream to become more amplified at times, the research claims, causing warmer air to travel further north than normal, and colder air to travel further south than normal - leading to more extreme warmth and cold.

A more amplified jet stream doesn't just mean long periods of poor weather for the UK. At the moment we are stuck in a trough in the jet stream, but we could just as easily be under the influence of a warm ridge, meaning longer periods of dry weather (and in summer, warm weather too).

Recent research has also pointed the finger at weak solar activity as a possible explanation for the cold, dry winters that Europe and the UK has experienced in the last few years.

These were caused by the jet stream being unusually far south, and the research conducted by Reading University concluding that such winters could become more common in the next decade or so as a result of expected weaker solar activity.

Whichever theory is correct - and it's plausible that both are exerting an influence at the same time - experiencing long periods of the same type of weather may be something we should get used to.

Albert Doyle
07-15-2012, 02:51 PM
Don't look at that proof behind the curtain.

Global warming is a liberal hoax.

Peter Lemkin
07-15-2012, 03:44 PM
Don't look at that proof behind the curtain.

Global warming is a liberal hoax.

Don't you be fooled...it's real [and my field]! Get used to it...we humans have fucked up the atmosphere and all else on the Planet. The proof has long, long been in on this. Some of the very people who created and ignored the problem may be trying to make some 'hay' out of it...but it is all too real. Trust me and trust the overwhelming part of the scientific community [except the usual suspects in the pay of Big Oil, Big Coal, Big Industry, et al.

Albert Doyle
07-15-2012, 07:06 PM
We obviously need a sarcasm icon...

Peter Lemkin
07-16-2012, 06:39 AM
Poland shocked by tornadoes, one dead

WARSAW | Sun Jul 15, 2012 2:01pm BST

(Reuters) - A freak wave of tornadoes ripped through northern Poland on Sunday, wrecking houses and swathes of forest and leaving one person dead and another 10 injured.

Tornadoes are not unknown in the European Union's largest eastern country but the scope and power of Sunday's twisters was unusual and comes in a summer already marked by flash floods, hailstorms and gales.

Some 1,200 rescuers were working to remove fallen trees, unblock roads and restore utilities in the hardest hit Baltic region of Pomerania.

Trees were uprooted, buildings damaged and power lines downed, while some 550 hectares of woodlands in the Tuchola Forest area were flattened.

"I saw a black column coming our way," an injured inhabitant of the Wycinki village, whose farm was destroyed by the tornado told state television. "It carried everything away with it ... birds, debris, sucked up water from the lake."

A caravan with a family of three inside was seen flying through the air in the village of Stara Rzeka and breaking into pieces upon landing, but its occupants suffered no serious injuries, news channel TVN24 reported.

"The sole fatality was a 60-year-old man in the Pomeranian village of Wycinki who was crushed to death by his collapsing summer cottage," fire brigade spokesman Pawel Fratczak told Reuters by telephone.

The tornadoes were the latest outburst of violent weather that has battered Poland since the start of the month with hailstorms, gales, cloudbursts and flash floods.

TVN24 reported meteorologists categorising the twister as a class two tornado with wind velocity of up to 200 km/h.

Magda Hassan
07-16-2012, 06:54 AM
Poland is hardly Tornado Alley is it? Very unusual.

Magda Hassan
07-16-2012, 06:55 AM
We obviously need a sarcasm icon...
Yes! Much is lost in translation. If you find any thing useful let me know and I can add it to the rest of them.

Peter Lemkin
07-16-2012, 07:13 AM
Poland is hardly Tornado Alley is it? Very unusual.

Hardly. Very unusual...as are the floods in Japan and China and increasingly violent weather worldwide. North America has experienced the warmest year ever and the driest since the 'dust bowl years'. North and Central America have seen a record number of hurricanes and the season is just beginning....the Arctic Ocean now has enough nation sized cracks in the ice for shipping companies to think of rerouting their ships that way. Normal climatic changes do occur, but over much longer periods of time. These are, according to all unimbedded climate scientists and statisticians, caused by human activities - mostly the tremendous increase in CO2 and methane in the atmosphere. It is all very sad....as were we to stop putting any more greenhouse gases in the atmosphere now [and we are actually increasing, not decreasing!] the average global temperature rise would likely be in the 2-5 degree C range - enough to melt the polar caps and Greenland ice sheet and flood many islands and much of the coastal cities. Some places will get colder; some warmer; some wetter; some dryer - almost all will experience more intense weather, as there is more energy in the atmosphere now. It actually effects other animals and plants more than it does humans, the wealthier of whom can to some degree move and adapt. Along with the changes I see in the Planetary political system, it is a very dim future unless we undergo an immediate about face in ethics and lifestyle.

Albert Doyle
07-16-2012, 01:24 PM
The usual deniers have gotten suddenly quiet on the internet.