Two cold-season derechoes in Europe

An analysis of selected cases of derecho in Poland

“…when the atmospheric circulation changed from S-SW to W-NW, rather than when the pressure gradient over Poland was at its highest (surface pressure difference of 35 hPa over 650-700 km). In Germany, between their northern and southern borders, there was a surface pressure difference of 45 hPa, corresponding to a pressure gradient of 5.5 hPa/100 km (Gatzen et al, 2011). The cold front crossed Polish territory in a mere few hours (Fig.…”

“…Much existing research on the emergence and development of derechos is concentrated in the USA (Johns and Hirt, 1987;Evans and Doswell, 2001;Bentley and Sparks, 2003), which is clearly linked to the number of occurrences recorded there (on average 15 cases per year compared to individual cases in Europe) . Both American and European studies focus primarily on the analysis of synoptic situations conducive to the formation of mesoscale convective systems (MCS) known to be the direct cause of derechos (Johns and Hirt, 1987;Coniglio et al, , 2011Coniglio et al, , 2012Gatzen et al, 2011;Pucik et al, 2011;Hamid, 2012). Another aspect taken up by the available research includes the identification of routes travelled by derechos and the zoning of areas of increased risk (Bentley and Mote, 1998).…”

“…9. Schema of the movement of the convective system that caused the derecho on 1 March 2008 (prepared by the author, based on radar data from the POLRAD system -Institute of Meteorology and Water Management,Gatzen et al, 2011 and http://essl.org/cgi-bin/eswd/eswd.cgi, http://europa.buienradar.nl, http://www.met.hu, http://www.meteomedia.de, http://www.meteox.com,http://www.ogimet.com).Fig. 10.…”

Hindcast experiments of the derecho in Estonia on 08 August, 2010: Modelling derecho with NWP model HARMONIE

“…There has only been one previously documented derecho event in Northern Europe, occurring in 2002 in Finland (Punkka et al, 2006). However, there have been several documented derecho events in Central, Western and Southern Europe (e.g., Gatzen, 2004;Gatzen et al, 2011;Hamid, 2012;López, 2007;Pučik et al, 2011;Gospodinov et al, 2014Gospodinov et al, , 2015Celiński-Mysław and Matuszko, 2014). Atmospheric conditions during derecho events and climatology of derechos have been widely studied in the United States (e.g., Evans and Doswell, 2001;.…”

Revisiting the synoptic-scale predictability of severe European winter storms using ECMWF ensemble reforecasts

“…The destructions caused by storm Lothar over central Europe in December 1999 revealed the importance of diabatic processes in a way similar to a diabatic Rossby wave for the rapid intensification of the storm over the North Atlantic (Wernli et al, 2002). The severe wind gusts observed during the passage of storm Kyrill in Jan-uary 2007 over central Europe finally emphasized the role of convection embedded in the cold front including the formation of cold-season derechos (Fink et al, 2009;Gatzen et al, 2011).…”