jet-stream images

For BBC programme

Five Miles High

Mike Blackburn,

Brian Hoskins

University of Reading

August 2007

Colours on the maps show wind speed

Arrows show the wind direction

all values are in metres per second

Slightly more than double (x2.2) to get miles per hour

Climatological jet-streams

Northern Winter DJF Southern Summer DJF

Climatological jet-streams

Northern Summer JJA Southern Winter JJA

Extreme seasons

Northern Winter (Climatology) Northern Winter 1963

Not very clear – next slide better – Atlantic sector

Extreme seasons

Northern Winter (Climatology) Northern Winter 1963

Note colour scale 15-45 ms-1

Persistent blocking anticyclone, diverting the jetstream

Leads to cold winters in western Europe (more continental)

Extreme seasons

Northern Summer (Climatology) Northern Summer 1976

Note colour scale 10-30 ms-1

Persistent blocking anticyclone, diverting the jetstream

Leads to hot summers in western Europe (more continental)

Extreme seasons

Northern Summer (Climatology) Northern Summer 2007

Note colour scale 10-30 ms-1

Very wet in UK and surrounding countries

Major UK rainfall events: June 13-15; June 25, July 20

Persistent waves on the jet-stream, with a trough of low pressure near the UK

Summer 2007 animation

Northern Summer 2007

3-day averages

Wind speed at 250 hPaThis is an animation in .gif format