29th May 2005: 00UTC
Within the frontal system (which is a bit harder to discriminate because of the enhancements) between Portugal and Marocco some convection is seen embedded. The green colours indicate a brightness temperature (BT ) of -50° C. Also over Greece the remnant of some CBs with cold cloudtops are seen.
29th May 2005: 01UTC
The development continues.
29th May 2005: 02UTC
The development continues.
29th May 2005: 03UTC
The development continues.
29th May 2005: 04UTC
Over Bulgaria few convective cells are observed. It is important to study the development of these cells in this area also the following hours. On the westcoast of Turkey an isolated cell can be spotted. The MCS embedded into the frontal system further develops as more icing is pictured in these enhanced IR images. Temperatures under -60° C are recorded (blue colour).
29th May 2005: 05UTC
The development continues.
29th May 2005: 06UTC
The development continues.
29th May 2005: 0645UTC
The development continues.
29th May 2005: 08UTC
The development continues.
29th May 2005: 09UTC
The development continues.
29th May 2005: 10UTC
The development continues.
29th May 2005: 11UTC
The convection over Turkey and Greece has further increased. Now isolated cells with BTs of up to –50° C are recognised. As a result of the induced sea breeze now also over Italy convection starts as in satellite the development of new cells becomes visible. Meanwhile in the warm sector over Eastern France the onset to convection is also clearly visible. Influenced by the orography over the Jura and Vogesen mountains some cells with BT of – 60° C are seen.
29th May 2005: 12UTC
Big MCSs can be seen over Bulgaria and Northern and Eastern Turkey. A long line of CBs is recognised along both coastal areas.
Convective cells over Eastern France also reveal further development.
29th May 2005: 13UTC
The development continues.
29th May 2005: 14UTC
The development continues.
29th May 2005: 15UTC
In Eastern Turkey the convection becomes less as the surface cools and subsidence prevails. The cells appear here now in red and orange which indicate a BT of – 40° C. At this timestep West-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 icing and the cold cloudtops appear as green in this enhancement. On the leading edge of the front over France also an increase in size of the convective cells is seen.
29th May 2005: 16UTC
Over the Swiss and the Austrian Alps now also some convection is seen. Due to orographic lifting some isolated convective cells can be resognised. In Eastern Turkey the convection becomes less. The green colours seen previous have changed to orange indicating less icing (BT of – 40° C). In Bulgaria and Greece some cells have “merged” into a large MCS.
29th May 2005: 17UTC
The development continues.
29th May 2005: 18UTC
In the warm sector ahead of the front, over Poland, Czech Republic and northside of the Alps, several very small convective cells are seen. In Bulgaria and Greece some cells have “merged” into one MCS.
29th May 2005: 19UTC
The development continues.
29th May 2005: 20UTC
The development continues.
29th May 2005: 21UTC
Explosive development of convection over northern France, Belgium and Luxemburg. BT of -70° C. Further south over Northern Spain, Andalusia and Gibralta more MCS are embedded into the system. The convection over the Balkan region is now more concentrated to Albania. Over Poland some remnant CB clusters are still observed.
29th May 2005: 22UTC
The development continues.
29th May 2005: 23UTC
The development continues.
30th May 2005: 00UTC
The explosive growth of convection within the frontal band continues. Three large MCSs are recognised in this image. Most remarkable is the first one over the Netherlands and Western German with BT of -70° C. Further south over Southern France and Southern Spain two large MCSs are seen.
30th May 2005: 01UTC
The development continues.
30th May 2005: 02UTC
The development continues.
30th May 2005: 03UTC
The development continues.
30th May 2005: 04UTC
The development continues.
30th May 2005: 05UTC
The development continues.
30th May 2005: 06UTC
The development continues.
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 potential triggering of convection.
30th May 2005: 09UTC
The development continues.
30th May 2005: 10UTC
The convection over Turkey has started. Some high reaching CBs are pictured inland as green and orange dots. Over Northern Romania the onset to another convection event is seen.
30th May 2005: 11UTC
The development continues.
30th May 2005: 12UTC
The development continues.
30th May 2005: 13UTC
A large MCS has formed over the Czech Republic at the leading edge of a front. In Austria most convection is now concentrated to the eastern part of the country as the front meanwhile also shifted more eastward.
30th May 2005: 14UTC
Over Rumania orographic lifting induced convection along the Carpathian Mountains (which contours can easily be witnessed).
The MCS system over Czech Republic and Austria are merging, forming a 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
The development continues.
30th May 2005: 16UTC
The storm over Poland has all the appearances of a so-called supercell. A very unusual feature can be seen over this supercell at 17:15 UTC whereby a plume of cloud appears to emanate from the cell and streams away in a northerly direction.
30th May 2005: 17UTC
Of particular interest is the formation of the ring-structure within the large cell over Austria and the Czech Republic. Most likely created by the building of a dome-like structure with a central area somewhat warmer than the edges. This central warmer area could be the result of the highest part of the dome reaching thermal equilibrium with the surrounding, warmer stratospheric air aftter approximately 15-30 minutes.
30th May 2005: 18UTC
The development continues.
30th May 2005: 19UTC
On the leading edge of a front a MCS is 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.
30th May 2005: 20UTC
On the leading edge of a front a MCS is covering Austria, the Czech Republic and Poland. The colours however have changed from blue to green, indicating less icing and decaying convectivity.
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
Most of the 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.
