Isotachs and Positive Vorticity Advection at 300 hPa

The maximum in the PVA field (red lines) can be found in the left exit region of the jet streak (yellow lines) coming from the north-west (top left corner of the image). The second maximum coincides with frontal cloudiness. It is located in the right entrance region of the jet coming from the south-west. The third maximum of the PVA is placed over eastern Turkey, in the left exit region of a relatively weak jet coming from the east.

For a better insight into the flow over larger area you can look at the wind field (isotachs and wind vectors) at 300 hPa.

A PVA maximum lies over frontal cloudiness contributing to the ascending motion and the enhancement of clouds at that position.

For a better insight into the flow over a larger area you can look at the wind field (isotachs and wind vectors) at 300 hPa.

The situation is similar to the one in previous image.

Wind field at 300 hPa over a larger area can be found here.

The PVA maximum over the cold front has slightly weakened. The most pronounced PVA maximum in this image is associated with the left exit region of the jet coming from the north-west and intensifying. This maximum corresponds very well with the enhanced cloudiness over Romania. The easterly jet stream is getting weaker and so is the PVA over eastern Turkey.

For a better insight into the flow over larger area you can look at the wind field (isotachs and wind vectors) at 300 hPa.

Convective clouds, which developed in the last 6 hours over eastern Turkey, are connected to the left exit region of the weak jet streak coming from the east. The PVA maximum is shifted a bit to the north.

Wind field at 300 hPa over a larger area can be found here.

The jet streak from the north-west is approaching Turkey and strengthening. The PVA maximum is located at the left exit region of the jet streak.

For a better insight into the flow over larger area you can look at the wind field (isotachs and wind vectors) at 300 hPa.

In the last 6 hours the second branch of the jet, the one over western Turkey, intensified. The PVA maximum at the right entrance region of that jet is in agreement with the enhancement of the clouds at that position. The weak jet stream from the east dies out.

For a better insight into the flow over larger area you can look at the wind field (isotachs and wind vectors) at 300 hPa.

Intensification of PVA at the left exit region of the jet streak over western Turkey can be noticed. The second PVA maximum, near the right entrance region of jet streak coming from the south, can be noticed over eastern Turkey. Despite of that, the convection is not intensifying anymore, showing that the position of jet stream and PVA maxima are not the only indication for the atmospheric instability.

The 300 hPa wind field on a larger domain can be found here.