Key Parameters

  • Temperature advection (WA):
    The ridge of WA is superimposed on the high level cloudiness representing the warm air rising on the upper level frontal surface.
  • Jet streak and positive vorticity advection (PVA):
    A jet streak approaches the cloud band at a large acute angle accompanied by a PVA maximum in the left exit region.
  • Humidity:
    Very dry values in the upper and middle troposphere above the low level cloud band and a strong gradient between the two cloud bands at different heights can be observed.
  • Relative streams and potential vorticity (PV):
    Typical configuration of relative streams as described in the Meteorological physical background, PV anomaly on relevant isentropic surfaces indicating stratospheric air.

30 August 2005/06.00 UTC - Meteosat 8 IR 10.8 image; red: positive vorticity advection (PVA) 300 hPa, yellow: isotachs 300 hPa