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Sheffield Weather Page

Weather Glossary

Jet Stream 

The jet stream consists of ribbons of strong winds that circulate the earth. The strength of the stream varies overtime and is split into two main flows. The subtropical Jet stream and the one that interests us most the Polar jet stream. This stream effects our weather most. The Jet stream tends to be between 23000ft and 39000ft above sea level. The flow varies stops, splits and meanders across the atmosphere. It’s direct location effects whether our weather will be unsettled or settled warm or cold. If we’re on the south side of the stream it tend to be milder while if we’re on the north side cooler.  The picture below shows a fairly active polar jet stream to the south of the UK. Low pressures embedded in the flow moving west to east.
The picture below show the jet splitting one branch going to the North while the other continues into Africa. This is called blocking which I will deal with later. This will also mean that Low pressure to the South West of the UK will swing North East and eventually stall and weaken as it loses the driving force of the Jet. 

Sting Jet 

The sting jet  was only recently recognized after the October Storm 1987. The Sting jet forms at the bottom of the hook in a low pressure system. It consists of very strong winds which luckily effect generally a very small area. The sting starts about 3 to 4km above ground which slowly descends towards the ground. Evaporative cooling increases the strength of the winds as the air becomes more dense sinking towards the surface. Winds can reach up to 100mph Sting jets form life span goes over four stages. The first stage (A) see diagrams below is where pressure first starts to drop, and two narrow jets of air form near the surface. Marked CJ for cold jet and WJ for warm jet. The low pressure system tends to be moving with the warm jet therefore the warm jet produces the strongest winds. The second stage (B) The Weather front Fractures shortly after the sting jet reaches the ground. The strongest winds now occur. The third stage (C) The sting Jet gradually grows larger over a period of a few hours. The fourth stage (D) The Cold jet finally wraps around the Low Pressure centre L and catches up with the Sting Jet. The worst of the winds are now over but strong gusts may still occur.  
Picture courtesy of http://www.wettergefahren-fruehwarnung.de
© Lorem ipsum dolor sit Nulla in mollit pariatur in, est ut dolor eu eiusmod lorem 2014
Sheffield Weather Page

Weather Glossary

Jet Stream 

The jet stream consists of ribbons of strong winds that circulate the earth. The strength of the stream varies overtime and is split into two main flows. The subtropical Jet stream and the one that interests us most the Polar jet stream. This stream effects our weather most. The Jet stream tends to be between 23000ft and 39000ft above sea level. The flow varies stops, splits and meanders across the atmosphere. It’s direct location effects whether our weather will be unsettled or settled warm or cold. If we’re on the south side of the stream it tend to be milder while if we’re on the north side cooler.  The picture below shows a fairly active polar jet stream to the south of the UK. Low pressures embedded in the flow moving west to east.
The picture below show the jet splitting one branch going to the North while the other continues into Africa. This is called blocking which I will deal with later. This will also mean that Low pressure to the South West of the UK will swing North East and eventually stall and weaken as it loses the driving force of the Jet. 

Sting Jet 

The sting jet  was only recently recognized after the October Storm 1987. The Sting jet forms at the bottom of the hook in a low pressure system. It consists of very strong winds which luckily effect generally a very small area. The sting starts about 3 to 4km above ground which slowly descends towards the ground. Evaporative cooling increases the strength of the winds as the air becomes more dense sinking towards the surface. Winds can reach up to 100mph Sting jets form life span goes over four stages. The first stage (A) see diagrams below is where pressure first starts to drop, and two narrow jets of air form near the surface. Marked CJ for cold jet and WJ for warm jet. The low pressure system tends to be moving with the warm jet therefore the warm jet produces the strongest winds. The second stage (B) The Weather front Fractures shortly after the sting jet reaches the ground. The strongest winds now occur. The third stage (C) The sting Jet gradually grows larger over a period of a few hours. The fourth stage (D) The Cold jet finally wraps around the Low Pressure centre L and catches up with the Sting Jet. The worst of the winds are now over but strong gusts may still occur.  
Picture courtesy of http://www.wettergefahren-fruehwarnung.de
© Lorem ipsum dolor sit Nulla in mollit pariatur in, est ut dolor eu eiusmod lorem 2014
Sheffield Weather Page

Weather Glossary

Jet Stream

The jet stream consists of ribbons of strong winds that circulate the earth. The strength of the stream varies overtime and is split into two main flows. The subtropical Jet stream and the one that interests us most the Polar jet stream. This stream effects our weather most. The Jet stream tends to be between 23000ft and 39000ft above sea level. The flow varies stops, splits and meanders across the atmosphere. It’s direct location effects whether our weather will be unsettled or settled warm or cold. If we’re on the south side of the stream it tend to be milder while if we’re on the north side cooler.  The picture below shows a fairly active polar jet stream to the south of the UK. Low pressures embedded in the flow moving west to east.
The picture below show the jet splitting one branch going to the North while the other continues into Africa. This is called blocking which I will deal with later. This will also mean that Low pressure to the South West of the UK will swing North East and eventually stall and weaken as it loses the driving force of the Jet. 

Sting Jet

The sting jet  was only recently recognized after the October Storm 1987. The Sting jet forms at the bottom of the hook in a low pressure system. It consists of very strong winds which luckily effect generally a very small area. The sting starts about 3 to 4km above ground which slowly descends towards the ground. Evaporative cooling increases the strength of the winds as the air becomes more dense sinking towards the surface. Winds can reach up to 100mph Sting jets form life span goes over four stages. The first stage (A) see diagrams below is where pressure first starts to drop, and two narrow jets of air form near the surface. Marked CJ for cold jet and WJ for warm jet. The low pressure system tends to be moving with the warm jet therefore the warm jet produces the strongest winds. The second stage (B) The Weather front Fractures shortly after the sting jet reaches the ground. The strongest winds now occur. The third stage (C) The sting Jet gradually grows larger over a period of a few hours. The fourth stage (D) The Cold jet finally wraps around the Low Pressure centre L and catches up with the Sting Jet. The worst of the winds are now over but strong gusts may still occur.  
Picture courtesy of http://www.wettergefahren-fruehwarnung.de