Wind, Waves & Weather

Wind, Waves & Weather

2601

Record hurricanes in the Atlantic, monster waves at Nazaré, sinking islands - look no further

2601
Phil
Phil added 3 photos to Avatar Photos album in Wind, Waves & Weather page 3 years ago

There's a useful Jet Stream forecast at www.westweather.co.uk/jetstream that goes up to ten days forward.

Equally interesting is the description below of the mechanics of a Jet Stream, and especially how Rossby waves can result in e.g prolonged wet summers whilst people are dying of heat just... Show more

There's a useful Jet Stream forecast at https://www.westweather.co.uk/jetstream that goes up to ten days forward.Equally interesting is the description below of the mechanics of a Jet Stream, and especially how Rossby waves can result in e.g prolonged wet summers whilst people are dying of heat just across the Channel in usually nice-to-go-places like Spain and Italy. And also France.In a nutshell - the Jet Stream is a band of fast moving air that blows from west to east - it separates the cold grey miserable polar air from the warm, continental 'just baked croissant'-flavoured stuff.The stream itself wanders slowly north and south across the UK - when it's south of us we are stuck in miserable grey days of Old London Town, when its to the north we get our flipflops out. So far so simple.But it's not the kind of steady stream that your Doctor asks for - ripples move from the east to the west that force it up and down the country temporarily - these are called Rossby Waves and they are independent of the speed of the oncoming stream..If the Rossby wave speed matches the opposite-flowing Jet Stream speed then conditions become static and we may see either a prolonged heatwave or wet season.A useful example is tomorrow 9pm's Jet Stream forecast (second image) vs XC Weather forecast (third image). The Jet Stream has completely looped south around the bottom of the country, leaving us in a pool of unsettled 'Polar' weather which persists until Thursday.As to how accurate the predictions are I have no idea, though most likely the further out they get the less accurate they become. Understanding the mechanics of UK weather may not make you feel any happier about our stolen summer, but it is some comfort to know what to blame... There's a useful Jet Stream forecast at https://www.westweather.co.uk/jetstream that goes up to ten days forward.Equally interesting is the description below of the mechanics of a Jet Stream, and especially how Rossby waves can result in e.g prolonged wet summers whilst people are dying of heat just across the Channel in usually nice-to-go-places like Spain and Italy. And also France.In a nutshell - the Jet Stream is a band of fast moving air that blows from west to east - it separates the cold grey miserable polar air from the warm, continental 'just baked croissant'-flavoured stuff.The stream itself wanders slowly north and south across the UK - when it's south of us we are stuck in miserable grey days of Old London Town, when its to the north we get our flipflops out. So far so simple.But it's not the kind of steady stream that your Doctor asks for - ripples move from the east to the west that force it up and down the country temporarily - these are called Rossby Waves and they are independent of the speed of the oncoming stream..If the Rossby wave speed matches the opposite-flowing Jet Stream speed then conditions become static and we may see either a prolonged heatwave or wet season.A useful example is tomorrow 9pm's Jet Stream forecast (second image) vs XC Weather forecast (third image). The Jet Stream has completely looped south around the bottom of the country, leaving us in a pool of unsettled 'Polar' weather which persists until Thursday.As to how accurate the predictions are I have no idea, though most likely the further out they get the less accurate they become. Understanding the mechanics of UK weather may not make you feel any happier about our stolen summer, but it is some comfort to know what to blame... There's a useful Jet Stream forecast at https://www.westweather.co.uk/jetstream that goes up to ten days forward.Equally interesting is the description below of the mechanics of a Jet Stream, and especially how Rossby waves can result in e.g prolonged wet summers whilst people are dying of heat just across the Channel in usually nice-to-go-places like Spain and Italy. And also France.In a nutshell - the Jet Stream is a band of fast moving air that blows from west to east - it separates the cold grey miserable polar air from the warm, continental 'just baked croissant'-flavoured stuff.The stream itself wanders slowly north and south across the UK - when it's south of us we are stuck in miserable grey days of Old London Town, when its to the north we get our flipflops out. So far so simple.But it's not the kind of steady stream that your Doctor asks for - ripples move from the east to the west that force it up and down the country temporarily - these are called Rossby Waves and they are independent of the speed of the oncoming stream..If the Rossby wave speed matches the opposite-flowing Jet Stream speed then conditions become static and we may see either a prolonged heatwave or wet season.A useful example is tomorrow 9pm's Jet Stream forecast (second image) vs XC Weather forecast (third image). The Jet Stream has completely looped south around the bottom of the country, leaving us in a pool of unsettled 'Polar' weather which persists until Thursday.As to how accurate the predictions are I have no idea, though most likely the further out they get the less accurate they become. Understanding the mechanics of UK weather may not make you feel any happier about our stolen summer, but it is some comfort to know what to blame...
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