MSG IR10.8 imagery with significant weather: time sequence

18th August 2004: 06UTC
The image shows a cloud area with a wave structure from Southern England to Northern Spain. A narrow band of deep convective clouds can be seen from western France to the Bay of Biscay. Here, occasional showers and light rain are reported. Some thunderstorms occurred near Paris. West of this cloud band we see deep cold air convection. The cloud spiral over England indicates the centre of a cyclone.

18th August 2004: 07UTC
The cloud area over Western France and the Biscaya moved to the East and narrowed.

18th August 2004: 08UTC
The cloud area covered large areas of France to the west of Paris.

18th August 2004: 09UTC
At 09 UTC we observe some rain and one heavy shower indicating that convection has begun to intensify. Near the observation of heavy showers the cloud top brightness increased.

18th August 2004: 10UTC
Over Western France some rain and showers occured. The cloud band narrowed and became brighter.

18th August 2004: 11UTC
Over Western France some rain and showers occurred in the area with deep convection.

18th August 2004: 12UTC
Close to the meridian the first thunderstorms occurred over France. These were situated at the leading edge of the cloud band.

18th August 2004: 13UTC
An intensification and an increased displacement of the front can be observed. The development of the squall line continued.

18th August 2004: 14UTC
An intensification and an increased displacement of the front can be observed. At the leading edge and central part of the squall line we recognise several convective complexes of multi cells in connection with a developing band of thunderstorms.

18th August 2004: 15UTC
Meanwhile, the squall line exhibited the typical structure of a long band of thunderstorms at the central and leading edge and showers and stratiform rain at its rear. The squall was several hundred kilometres long

18th August 2004: 16UTC
The squall line moved rapidly to the Northeast and started to broaden. Over Belgium we find two reports of severe thunderstorms. The length of the cloud band was more than 500 km long.

18th August 2004: 17UTC
Many thunderstorms developed along the squall line in an area extending from Belgium to Central France. The squall line arrived over Western Germany and the first thunderstorms were observed.

18th August 2004: 18UTC
With a velocity of about 100 km per hour the squall line moved eastwards and broadened. Deep convective clouds covered an area from Western Germany to Central France. Many thunderstorms, occasionally with hail, were reported within the central part of the cloud band.

18th August 2004: 19UTC
With a velocity of about 100 km per hour the squall line moved eastwards.

18th August 2004: 20UTC
The squall line covered most of Western Germany and started to weaken.

18th August 2004: 21UTC
With a velocity of about 100 km per hour the squall line continued to move east. The observations show convective rain in the central and leading part of the squall and stratiform precipitation at the rear. Reports of thunderstorms or sheet-lightning stretched for almost 1000 kilometres.

18th August 2004: 22UTC
The squall line covered most of western Germany and moving quickly east. Due to the high wind speed in the upper altitudes the high cirrus clouds were transported very quickly eastwards and by 2200 UTC were over the Oder. Northwest of the Alps a new convective complex developed.

18th August 2004: 23UTC
From 22 UTC to 23 UTC the squall line slowed and weakened. We can still see some thunderstorms, however, these are mainly over the northern and middle parts of Germany. Over Eastern France and West Germany prevailing stratiform rain was reported.

19th August 2004: 00UTC
The convection continued weakening. We observe prevailing rain and some showers and only a few thunderstorms.