Sometimes I notice that if I'm ‘researching’ the jet stream phenomena I often come across statements from meteorologists that sound like the following
1. The Jet stream moves because of weather (e.g. warmth or cold somewhere) and or
2. The weather is like it is because of the Jet stream.
Both may be true to an extent but it needs to be clear, the jet stream IS weather so what we really have here is confusion on a description rather than cause.
The question is WHY are it ( the jet stream) and our associated weather behaving rather differently now than say from a decade ago? That’s not for me to say or conclude.
‘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. A low lying jet stream is also connected to AMO see this post here on Striper bass decline
The risk here is that we incorrectly associate animal behaviour and rationalise exceptions into slots that ‘fit’ our derivations. Ants are flying early or badgers are blacker than white this year – and then we attach a weather pattern as either the cause or the displayed animal behaviour is an indication the end the world is approaching!
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.
'The jet stream, for some time now, has been further south than normal - hence the inclement weather.
During 2007, 2008, 2009 the Jet Stream has been at an abnormally low latitude across the UK, lying closer to the English Channel, around 50°N rather than its more usual north of Scotland latitude of around 60°N. However, between 1979 and 2001, it has been found that the position of the jet stream has been moving northward at a rate of 2.01 kilometres (1.25 mi) per year across the Northern Hemisphere'
From my own observations based on fish returns and expectations you could draw some conclusions see here A challenging season, fish behaviour changes because of weather – this has been inherent in this blog for a long long time.
I do know this – when I started guiding in 2003 my ‘management’ of how the weather was communicated to customers at the beginning of the week along with the information pack and the detail etc., the summary went something like this – ‘Guys, looks like we will have a tough day on Tuesday and fishing will be difficult until Wednesday lunchtime’, (or something similar) at the moment I’m looking for a good day amongst several tough or impossible days!
Looking at this forecast it looks like its set to remain difficult for a while.