29th May 2005: 00UTC
A rough comparison with the surface analysis of the 29th of May shows that western Europe is governed by a frontal system. Over Spain some convective cells are embedded whereas further north over the Netherlands and Danmark the frontal band has more or less decayed (probably caused by NVA in right exit region of a jet streak, see fibrous clouds over Atlantic). The Occluded part of the band is found north of Scotland over the Faroe Islands. On the leadinge edge of this front convective development will be seen in the following hours. Over the Balkan region the remnants of some CBs are seen. Under influence of daytime convection more development will be seen here as well.
29th May 2005: 01UTC
The remnants of the Balkan are persistant and move to the SW.
29th May 2005: 02UTC
The remnants of the Balkan are persistant and move to the SW.
29th May 2005: 03UTC
The remnants of the Balkan are persistant and move to the SW.
29th May 2005: 04UTC
The remnants of the Balkan are persistant and move to the SW.
29th May 2005: 05UTC
The convective development over Turkey and Greece gets underway as now more isolated cells are seen. Up north some activity (thunderstorms and rain e.g.) may be expected in Estonia as an MCS embedded into the frontal system can clearly be seen.
29th May 2005: 06UTC
The development continues.
29th May 2005: 0645UTC
The development continues.
29th May 2005: 08UTC
Within the frontal band over Western Europe some convective cells are embedded. However new cells developing at the leading edge of the frontal band are not (yet) seen. At this phase the increasing level of convectivity over the Balkan region is more evident. Several convective cells seem to merge as they further develop.
29th May 2005: 09UTC
The development continues.
29th May 2005: 10UTC
The development continues.
29th May 2005: 11UTC
In the warm sector over Eastern France the onset to convection is also clearly visible. Influenced by the orography over the Jura and the Vosges mountains in France some cells are seen.
29th May 2005: 12UTC
The development continues.
29th May 2005: 13UTC
The development continues.
29th May 2005: 14UTC
The development continues.
29th May 2005: 15UTC
At this timestep entire Turkey, Greece and the rest of the Balkan region as well as Italy and Sicily are indulged by convection. Most of the cells have merged forming large MCSs. The iceparticles in the cloud cause the cells to appear as bright/white. On the leading edge of the front over France also an increase in size of the convective cells is seen. Triggered by the orography also over the Austrian Alps developing cells are observed.
29th May 2005: 16UTC
The development continues.
29th May 2005: 17UTC
The development continues.
29th May 2005: 18UTC
In the warm sector ahead of the cold front, over Poland, Czech Republic and northside of the Alps, several convective cells are seen.
29th May 2005: 19UTC
The development continues.
29th May 2005: 20UTC
Explosive development of convection over northern France, Belgium and Luxemburg. The MCS is easily spotted and its development should be looked at in following images. Further south over Northern Spain, Andalusia and Gibraltar more MCSs are embedded into the system. The convection over the Balkan region is now more concentrated to Albania where a large MCS is observed.
29th May 2005: 21UTC
The development continues.
29th May 2005: 22UTC
The development continues.
29th May 2005: 23UTC
The development continues.
30th May 2005: 00UTC
The development continues.
30th May 2005: 01UTC
The horizontal widening of the cirrus cap, within the frontal band, continues. Three large MCSs are recognised in this image. Most pronounced is the first one found over the Netherlands and Western Germany. Further south over Southern France and Southern Spain two large MCSs are seen.
30th May 2005: 02UTC
Decay of the cells over Germany is witnessed.
30th May 2005: 03UTC
Decay of the cells over Germany is witnessed.
30th May 2005: 04UTC
Decay of the cells over Germany is witnessed.
30th May 2005: 05UTC
Decay of the cells over Germany is witnessed.
30th May 2005: 06UTC
Decay of the cells over Germany is witnessed.
30th May 2005: 07UTC
The development continues.
30th May 2005: 08UTC
Comparison with the previous images reveals a cyclonic flow of clouds over central Turkey, probably due to the existence of a region of low pressure. This situation should be looked at the following hours as it can be a sign of a lable atmosphere and trigger for convection.
30th May 2005: 09UTC
The convection over Turkey has started. Some high reaching CBs are pictured inland as the white bright spots. Over Northern Romania the onset to another convective event is seen.
30th May 2005: 10UTC
The development continues.
30th May 2005: 11UTC
The level of convection in Turkey has increased. As daytime convection gets underway several isolated CBs are recognised over the Carpathian Mountains, Bulgaria, Sicily, Czech Republic and on the southside of the Austrian Alps, all influenced by the orography.
30th May 2005: 12UTC
Turkey is engulfed by convection. Over Central Europe a second large convective event is set to start. Influenced by the orography over Central Austria several cells are recognised. Further north over the Czech Republic and Poland also high reaching CBs are observed.
30th May 2005: 13UTC
The cells just discussed at the leading edge of the frontal zone have further increased. Whereas the northern cells are clearly influenced by the frontal zone, the cells over Austria and Rumania were triggered by orography.
30th May 2005: 14UTC
The MCS system over Czech Republic and Austria are merging forming a huge MCS on the leading side of a front. Over Italy and Croatia several thunderstorms are observed. Also in Greece (especially along the coast) several isolated convective cells are seen. These cells will be studied using radar at a later stage of this case study.
30th May 2005: 15UTC
One huge MCS system now formed covering parts of Austria, the Czech Republic and parts of Poland. The MCS formed over the past few hours on the leading side of the N-S front over western Europe.
The storm over Poland has all the appearances of a so-called supercell. A very unusual feature can be seen over this supercell whereby a plume of cloud appears to emanate from the cell and streams away in a northerly direction.
Parts of Croatia, Albania, Greece, Bulgaria are also still covered by numerous convective cells.
Interesting is also the chain of convective cells which has formed over the border of White-Russia and the Ukrain and Russia. These probably developed as a cause of shear between the two dominant flows.
30th May 2005: 16UTC
The development continues.
30th May 2005: 17UTC
As day almost ends in Turkey the level of convection dies out as it appears more grey in the satellite image. Over the Balkan region and Central Europe several convective cells can still be observed. Most important feature in the image still remains the MCSs over Austria, Czech Republic and Poland.
30th May 2005: 18UTC
Convection over Balkan area is further decaying.
30th May 2005: 19UTC
Convection over Balkan area is further decaying.
30th May 2005: 20UTC
On the leading edge of a front MCSs are covering Austria, the Czech Republic and Poland. The second area of interest in this case study also still shows some convection; Isolated cells are covering the coastal region of Greece. More inland on the border with Bulgaria a larger CB is observed. Also over Western Turkey several small cells merged into one bigger cell.
30th May 2005: 21UTC
Convection is decaying.
30th May 2005: 22UTC
Over Western Turkey and the Egean Sea near Greece two MCSs are observed. Other convective regions are embedded into the frontal system over Western and Southern Europe.
