During the period 17–20 June 2013, central Europe experienced the first heat wave (four consecutive days above 30 °C) of the year.
01 August 2022
18 June 2013
By Jochen Kerkmann (EUMETSAT) and Martin Setvak (CHMI )
In Germany, temperatures reached 37°C, which, combined with the high humidity (dew points around 20°C), caused a 'red alarm' for extreme high temperatures on Meteoalarm.
During this heat wave EUMETSAT, at the request ESSL , conducted two 2.5-minute rapid scan sessions with Meteosat-8 (MSG-1), on 17 and 20 June.
These experimental rapid scans link up to similar tests performed with Meteosat-10 (MSG-3) during its commissioning phase, 11–12 September 2012, and with Meteosat-8 on 17 May 2013.
The data from these tests will be used as preparation for MTG (Meteosat Third Generation), which will carry the FCI (Flexible Combined Imager) instrument. The FCI will be able to scan either the full disc in 16 channels every 10 minutes with a spatial sampling distance in the range 1-2km (Full Disc High Spectral Resolution Imagery (FDHSI) in support of the Full Disc Scanning Service (FCI-FDSS)) or a quarter of the earth in four channels every 2.5 minutes with doubled resolution (High spatial Resolution Fast Imagery (HRFI) in support of the Rapid Scanning Service (FCI-RSS)).
On 18 June the second day of the heat wave, several convective storms developed explosively over eastern Germany, the Czech Republic and Poland (see Meteosat-9 rapid scan (5-minute) animations and the synoptic situation at 12:00 UTC from the 500hPa ECMWF analysis overlaid on the airmass RGB product, (Credit: EUMeTrain).
Many of the storms, including the one over eastern Germany close to Erfurt (see Figure 1), developed distinct cold ring-shape cloud tops, which is a well-known satellite indicator for possible severe weather on ground.
Many storms also showed a yellow colour in the ice particle size RGB and the so-called storm RGB (blending of HRV and ice particle size RGB), which indicates the presence of small ice particles in the top part of the thunderstorms.
In the evening, between 17:00 and 18:30 UTC, a large thunderstorm complex over the eastern Czech Republic produced an amazing 'firework display' of overshooting tops, embedded warm areas and plumes.
According to the European Severe Weather Database, the storms over Poland and the Czech Republic were accompanied by severe weather, including two tornadoes — one in north Moravia (Krnov), the other one in southwest Poland — and large hail (up to 6 cm diameter). However, the storm close to Erfurt was not severe (no reports for this storm) and it quickly dissipated between 15:00 and 16:00 UTC.
Interestingly, a series of photos of the storm close to Erfurt was taken by Jochen Kerkmann on a Lufthansa flight from Rome to Frankfurt (13:15– 15:15 UTC, see Figures 2 and 3 below and this powerpoint presentation (Credit: Jochen Kerkmann).
The photos show so-called jumping cirrus on top of the Cb anvil of the ring-shape storm shown in the IR image. The jumping cirrus stayed there for several minutes, until the airplane was too low to see it anymore. The name 'jumping cirrus' comes from a phenomenon observed by Fujita in the 1980s who reported that "one of the most striking features seen repeatedly above the anvil top is the formation of cirrus cloud which jumps upward from behind the overshooting dome as it collapses violently into the anvil cloud". Some information on jumping cirrus and their simulation with models is presented in this zipped powerpoint presentation by Prof. Pao Wang.
The white line represents approximate flight track of LH flight from Rome to Frankfurt.
White dashed lines denote view of photos shown below, with the cold ring-shape storm over Thüringen area (close to Erfurt).
At the time of the photo, the airplane had just started to descend to Frankfurt airport; flight level was around 24000ft. Image processed with Adobe Photoshop by Martin Setvak.
Figure 3 is the photo taken one minute before the previous photo, shows a zoom (x3) of the storm with the jumping cirrus. Image processed with Adobe Photoshop by Martin Setvak.
Meteosat-10 HRV loop taken over France on 19 June (animated ). Taken one day after the case above it shows numerous cloud top features like overshooting tops, gravity waves, plumes and ship waves.