Single cell thunderstorm cloud

Thunderstorms over Hungary, Romania & the Ukraine

14 June 2010 12:55 UTC

Single cell thunderstorm cloud
Single cell thunderstorm cloud

On 14 June several convective clouds and convective systems developed in the Carpathian basin and to the east of it.

Last Updated

05 May 2023

Published on

14 June 2010

By Mária Putsay, André Simon (Hungarian Meteorological Service) and Jochen Kerkmann (EUMETSAT)

A frontal system propagated over Hungary, Slovakia and Poland towards east. There was a southerly inflow of very unstable air in front of the system, which, together with the presence of moderate wind shear, favoured the development of organised convection. From about 9:00–10:00 UTC a large mesoscale convective system (MCS) started to develop east of Budapest. Notable features include cold ring-shaped storms, gravity waves around the thunderstorm anvils and radial cirrus clouds (source: M. Putsay, Hungarian Met Service).

Figure 1: Meteosat-9 HRV and IR10.8, 14 June 10:00-18:00 UTC

The system moved towards the east, grew rapidly, and in three hours it covered a quarter of the country and a large part of Slovakia, later spreading over Romania and Ukraine. It persisted for about 10 hours. The MCS showed severe weather features. Strong wind, hail (up to 6cm), sudden and intense rainfall, and intense lightning activity was observed. An arc cloud on the approaching gust front was photographed at 12:38 UTC by Csaba Rácz at the city of Debrecen (see radar reflectivity image, with the position of the observation and the viewing angle of the photograph).

We could follow the development of the MCS on the Meteosat-8 rapid scan (5-minute data) imagery (see animation, HRV/IR10.8 blended, 10:00–18:00 UTC). The frames were created by overlaying semi-transparent IR10.8 infrared images on HRV images, a method introduced by Martin Setvák (see e.g. case study Backbuilding storms between Tunisia and Sicily, 23 September 2009).

On such animations one can see at the same time the cloud top temperature distribution, including a cold ring, and the cloud top topography, such as overshooting tops, gravity waves and radial cirrus. In our case we could see several long-lived cold rings (e.g. at 10:45 UTC), gravity waves (e.g. at 11:55 UTC), radial cirrus and overshooting tops (both at 12:55 UTC). Note that at this time the overshooting top was almost in the middle of the warm spot.

Met-8, 14 June 2010, 12:55 UTC
Figure 2: Meteosat-8 Channel 12 (HRV) blended with Channel 09 (IR10.8), 14 June 12:55 UTC
Met-8, 14 June 2010, 15:45 UTC
Figure 3: Meteosat-8 Channel 12 (HRV) blended with Channel 09 (IR10.8), 14 June 15:45 UTC

By evening, a series of intense overshooting tops were visible like a 'boiling surface' at low solar elevation (15:45 UTC). Between 16:10 at 17:30 UTC intense gravity waves could be detected at the south end of the system (e.g. at 17:00 UTC , even better visible in the animation, 10:00–18:00 UTC). The overshooting tops and gravity waves are well shown in the higher spatial resolution NOAA-19 channel 1 image taken at 11:03 UTC. The western system is the Hungarian MCS, the others are over Poland and the Ukraine.

In the 4-panel animation (07:00–17:30 UTC), showing coincident 15-minute Meteosat-8 and radar data, it is possible to look separately at the IR10.8 channel, the HRV cloud RGB (RGB HRV, HRV, IR10.8), the 'convective storms' RGB and radar images (column maximum logZ). Bow echoes can be seen on the 12:15 UTC and 15:45 UTC radar images indicating strong outflowing winds over the east of Hungary and northwest of Romania, respectively. Very high numbers of lightning discharges were observed, see the animation of radar and 10-minute lightning data (black points, 07:45–16:45 UTC) . The intense lightning activity also caused some damage, as several fires occurred.

Large amounts of precipitation (up to 42.4 mm in one hour, from daily records of automatic stations) fell in many places, causing severe damage. Roads were covered by flooded water and mud. Several agricultural sites were destroyed by hail covering several hectares. The MCS caused severe wind (wind gust up to 34.4m/s, from daily records of automatic stations) in many places, mainly due to thunderstorm outflows.

The strong wind uprooted many trees and destroyed the poles carrying electric power lines. Some villages were without electricity during several hours. Even big, healthy trees fell to the ground, as the soil was already unusually wet due to the extreme amount of precipitation during the previous months. Several trees fell on roads and rails, causing transportation jams. The wind or the falling trees damaged or even destroyed the roofs of several thousand houses in the Szabolcs and Szolnok regions.

Around 11:00 UTC one could see low-level wave clouds on the eastern flank of the main cell. It was probably related to wind shear and the presence of a temperature inversion in the inflow region (supported by the 0:000 UTC Szeged and 12:00 UTC Belgrade soundings). According to ECMWF forecasts from the 14 June 2010 00:00 UTC run, the airmass south of the MCS had a very high CAPE (almost 4000 J/kg), however, the presence of a low-level inversion and of drier air aloft suppressed the generation of convection.

The low-level waves were well visible at 11:25 UTC on the blended HRV-IR image, on the HRV cloud RGB image (see the lower right panel) and on the animation (HRV/IR10.8 blended, AVI, between 11:10–12:10 UTC).

Additional content

Met-9 HRV image (13:00 UTC)
Met-8 HRV animation (07:30–13:35 UTC)