12:00

The area of SE Belgium, with nothing to report of significance on the radar at this time, apart from a few light echoes which indicated shower growth.

13:00

An hour later, small individual cells start to form north-west of high ground.

13:30

13:45

One large thunderstorm now becomes established with anvil rainfall spreading
upwind to the NW. Rainfall rates depicted in black are >32mm/hr.

14:00

The main core of the storm increases and begins to elongate. The small red symbols
are showing actual ground observations of thunderstorms.

14:15

As the radiating anvil stretches further NW, the core begins to split, with the western cell-split maintaining a track consistent with the north-westerly flow, but the eastern cell
beginning to 'right-move' to the north.

14:30

The two cells now split completely, with the larger eastern cell showing definite 'right-movement'to the north, 45 degrees to the main flow. Note the radiating anvil, and also
the most easterly part of the larger cell core....

14:45

The smaller cell now diminishes, but the right-moving larger cell starts
to develop a well-defined hook-echo.

From this point, the storm amalgamated with more thunderstorms moving up from the south.This cell produced flooding and large hail, with reported fatalities. The storm splitting, impressive right-movment of the northern cell, and the development of a hook echo leaves no doubt that this Belgian storm was an impressive European supercell.