In connection to a project with the ECMWF, this year at the ESSL Testbed, different approaches for CAPE calculations are offered in the testbed data display:
It means that in addition to the standard CAPE – which is provided by ECMWF operationally – we try to compare with the usability of other approaches, namely with a mixed layer CAPE of the lowest 50 or 100 hPa alternatively, the surface parcel CAPE and the most unstable CAPE for situations of elevated CAPE, which does not show up in calculations that use close-to-surface parcels. In addition a combined plot is offered that displays both mixed layer and most unstable CAPE in combined colour shaded and colour contour plot.
Monday’s and also yesterday’s forecasting teams at the ESSL Testbed did an amazing job by forecasting the severe weather threat over the region stretching from northern France to the northern parts of the Netherlands.
A level 2 was issued, and according to the current amount of severe weather reports entered into the ESWD it can already be said that the forecasts verified very well. A subjectively nearly perfect forecast was the day 2 forecast issued on Monday:
Western Europe and also the Danube delta region close to the Black Sea are some of the hotspots for the first testbed forecasts. This time we start with redesigned model maps and an improved roaming sounding tool, to name just two of the enhancements at the ESSL Testbed this year.
The height of convective cloud tops is not only interesting for aviation, but also for case studies of severe storms and of course for nowcasting.
A case of yesterday showed the eyepicking nature of an alternative colour scale for a severe storm near Zaragoza in Spain with tops between 15 and 16 km of height (see magenta pixel). A positive reaction to this display was also received on Twitter.
NWC-SAF cloud top height product with alternative colour scale being tested at the ESSL Testbed
For the day 1 forecast group it is important to compare model output moisture with recent observations from different sources, like surface obs, soundings or satellite retrievals. On the following photo the precipitable water for the lower troposphere is watched by the ESSL Testbed participants (and there is also a difference-to-model product available this year):
EUMETSAT NWC-SAF PW low layer product used for day 1 forecast
Focused model studies (including model soundings) in the day 2 forecast group this morning:
During the afternoon one of the forecast groups typically works on the day 3 – 5 forecast, also today:
This week Helge Tuschy from DWD (standing in front of the screen, also active on ESTOFEX) supports the ESSL team at the testbed in steering one of the forecast groups.
Example for a day 5 forecast (issued on Tue last week):
Day 5 forecast with verification (lighning density in blue, ESWD severe weather reports: symbols). The southeastern severe weather area verified quite well, while hailstorms over northern Spain were not forecast 5 days in advance.
Today’s expert lecture was given by Abdullah Kahraman from Samsun University in Turkey on the topic of severe storms climatology: extremely large hail for example has been observed several times in Turkey.
Abdullah Kahraman at the ESSL Testbed on severe storms climatology for Turkey
During lunch Testbed participants could see how well the COSMO-2 was able to predict the local initiation of storms in this case. At the end we had to rush back to the office because of approaching thunder.