Pakistan floods and Russian heatwave, July 2010
Mike Blackburn, Andy Turner, Brian Hoskins
Read a statement on the recent extreme weather.
Further information is available as a Walker Institute news article.
Animation
of potential temperature on the dynamical tropopause for the last week of July 2010.
There was a blocking anticyclone over western Russia (theta ~ 330-350K) and equatorward flow on its eastern flank, near 70degE. Subtropical wave-breaking events occured over the eastern Atlantic, with downstream development of waves over the Mediterranean and further east on the subtropical jet. When these waves came into phase with the block, air was advected from far northern latitudes into the trough near 70degE, in close proximity to tropical air in the monsoon anticyclone. This generated a strong jet streak over the Tibetan plateau in the final days of July.
Animations for previous weeks:
02-09 July
09-16 July
16-23 July
Jet stream winds -
weekly average
for the last week of July 2010 compared with
climatology.
Note the strong jet feature over Tibet, with its entrance close to northern Pakistan. This configuration would give geostrophic forcing of ascent on the equatorward side of the jet entrance.
Animation
of daily jet stream winds for July and early August 2010.
Evolution of monsoon depression in last week of July, using an
animation
of 850hPa winds, courtesy of IPRC, University of Hawaii.
Satellite
animation, using infra-red channel on Meteosat at 57E, every 6 hours. Note the elongated cloud band associated with the jet streak that develops on 28 July, with embedded deep convective cloud over northern Pakistan.