Meteo Consult, Wageningen - Netherlands
In this study, the structure of a bow-echo on a squall line is investigated. On June 7, 1997 severe storms developed over northern France and merged into a squall line. It accelerated as it moved into the Netherlands. A bow-echo developed over extreme northern Belgium with unidirectional vertical shear of order 20 m/s over a depth of 5 kilometer and CAPE-values between 1800 and 2200 J/Kg. Along the gustfront gusts over 75 knots were measured. The international airport Amsterdam closed for a short time and widespread damage was reported in the western parts of the Netherlands. Particulary interesting was the damage along the path of the bow-echo which was extreme. On the intersection of an pre-existing convective boundary and the cyclonic apex of the bow, a short lived F0-F1 tornado developed. This was a very dangerous situation as it was during the weekend with a lot of people on the lakes and just off the dutch coast. This paper will assess the synoptic environment in which this squall line evolved, as well as the mesoscale features of the bow echo (e.g. the Rear Inflow Jet), including radar-reflectivity and profilerdata.