Alltrikes

From the Oz Report today:

Sting Jets

Tue, Nov 5 2013, 8:09:37 am PST
High winds around the center of a low pressure

Cross Country writes:

This week's tip comes in the wake of the storm that has swept through much of northern Europe over the past couple of days.  Winds of 170km/h caused disruption and damage.  Broadcasters said much of the damage was caused by a 'sting jet' in the wake of the storm.  But what is a sting jet?

Sting jets were identified following the 'hundred year storm' that swept through the UK in 1987.  They are now known to be the cause of the most damaging winds in European windstorms.

Researchers found that the most damaging winds in low pressure areas occur in a very small region, perhaps only 50km across.  This is 'mesoscale' – the same scale as sea breeze fronts or squall lines.

This area is close to the 'tail' of the 'head' of cloud that wraps around the centre of the low pressure.  This cloud, hooked like a scorpion's tail, gives the wind region its name.  The wind starts out three or four kilometres above the ground and descends over three or four hours.

Snow and rain falling into it evaporate and cool it as it descends.  This evaporative cooling means the air within the jet becoming denser – and faster.  This really is the low pressure's 'sting in the tail' – the part of the storm that will do the most damage when it hits the ground.  Wind speeds of more than 150km/h are associated with a sting jet.

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I found an image of a "Sting Jet" HERE: