INCA - Wind and MOCON analysis

ALADIN 10 m wind, 18 September 2007, 06 UTC

The image shows the 10m wind field as forecasted by ALADIN-SI 00 UTC run (6-hours forecast). Arrows show the direction of the wind and color shades give the wind speed in m/s, according to the scale at the bottom of the picture. The spacing between the wind arrows is 9 km.

It can be seen that there is a more or less homogenious S or SW flow over Slovenia.

INCA 10 m WIND, 18 September 2007, 06 UTC

INCA wind analysis, shown for the same time as the ALADIN wind field, gives much more details, since the model wind field is down- scaled and the real-time wind measurements are taken into account.

In the north-western part convergent flow is clearly seen in the valleys of Gorenjska to the north and near town Škofja Loka (central). This was an important indication of the conditions favorable for triggering of convection.

INCA wind and MOCON, 18 September 2007, 12 UTC

INCA wind analysis combined with the field of moisture convergence in the PBL (MOCON) is shown. Areas of moisture convergence are coloured red and in blue there are areas with divergence. The area of convergence visible in the western Slovenia coincides with the location, where new convective cells were constantly triggered in the following hour. That can be also be seen on the radar image taken 30 minutes after the analysis time.

The study of this case encurages forecasters to look more into the details of INCA analyses in similar situations.