2nd October 2007: 12UTC
This is the first of two images for 2nd October at 12UTC. The images were composed of the 06UTC run. Areas with a maximum of precipitable water are found over the relatively warm Mediterranean Sea and Atlantic Ocean. That the ocean is suiatbel for some convection is also seen in the CIN which shows low values favourable for the onset of convection in emre unstable areas. Bottom left is the WINX that gives indication for downbursts. Such indications can be seen over Southern Spain and Northern Africa (Algeria). These areas also correlate quite nicely with the corresponding enhanced IR10.8 image that is pictured below.
Meteosat 9: Enhanced IR10.8 - 2 October 2008 12UTC
2nd October 2007: 12UTC
If we look at the top two images we see on the left the lifted index and to the right the CAPE. One sees that ove rthe Atlantic of the coast of Morocco and over Northern Africa in Algeria we have unstable areras. The Area over the Atlantic corresponds nicely with the clusters of CBs that are embedded to the frontal band. These areas also come forward in the combined ACON image (bottom right) which combines these stability parameters.
Meteosat 9: Enhanced IR10.8 - 2 October 2008 12UTC
2nd October 2007: 18UTC
Another 6 hours later and over Morocco and Algeria the convection has started. Over the Strait of Gibraltar even a fierce V-shaped structure can be seen. The severeity int his area is fortunately also seen in the HIRLAM model by high values up to 50 mm for PW. The onset of convection is not beign hampered by a strong cap as the CIN shows low values for most of the entire Iberian Peninsula. Indication for downbursts are seen over Cádiz and Malaga in Southern Spain and further north towards the center in Ciudad Real.
Meteosat 9: Enhanced IR10.8 - 2 October 2008 18UTC
2nd October 2007: 18UTC
The top two images with the lifted index and to the right the CAPE again also help us to identify the areas which are most unstable. Over the Atlantic, of the coast of Morocco, and further up north into Spain and Portugal but also in Algeria we have unstable areras. These areas also come forward in the combined ACON image (bottom right) which combines these stability parameters. These areas are however less emphasies by the enahnced IR10.8 image we see below.
Meteosat 9: Enhanced IR10.8 - 2 October 2008 18UTC
3rd October 2007: 12UTC
The severest convective activity that happened over night has now almost dissapeared. The depression or cold core low has moved towards the Portuguese Southcoast which is seen in the Temperature at 50 kPa. (top righ image - white solid line) and on the direction of the wind barbs (bottom right). Over northern Spain the IR image still shows us some convection which corresponds quite well with the high values of PW and the moisture convergence at 85 kPa (both top left).
Meteosat 9: Enhanced IR10.8 - 3 October 2008 12UTC
3rd October 2007: 12UTC
Within the depression of the cold core low (SW of Portugal) some core convection has developed in the cold air. The development happened in a mere unstable area with negative LI up -2 and a CAP ranging from 400 to 1100 J Kg-1. In the combined ACON image to the bottom right also this core convection is stressed as an area which should be attention to also in future hours.
Meteosat 9: Enhanced IR10.8 - 3 October 2008 12UTC
3rd October 2007: 18UTC
The convection over Spain is becoming less and less. Over Algeria however the below enhanced IR10.8 image shows us two large MCSs and it is therefor interesting to look at the HIRLAM model for this area. Obvious it shows us already high indication for precipitable water with values up to 50 mm and and a small local maximum of moisture convergence at 85 kPa. Although the convection has already started, over the African continent the further development of convection may somewhat be hampered by a strong cap (top right).
Meteosat 9: Enhanced IR10.8 - 3 October 2008 18UTC
3rd October 2007: 18UTC
The last image of this set. Over the before discussed region in Algeria also the lifted index is negative with values of up to -4°C. The CAPE itself is less convincing with values ranging between 100 to 400. This is also seen in the combined ACON image (bottom) right that with the low CAPE in combination with the strong CAP shows no specific areas for development of deep convection. One last remark may be pointed to the SRH (bottom lef) or Storm Relative Helicity which is a measure of the helical flow or low level shear of a moving thunderstorm. The area we see here as values up to 500 m2 s-2 and depicts us at this stage quite nicely the regions where we in the IR image see some convective cells.
Meteosat 9: Enhanced IR10.8 - 3 October 2008 18UTC
