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