Weather pictures & report of May 1 2008


Isolated shower of rain and small hail.

Synopsis: at 500 hPa an upper trough over the U.K. advecting unstable air into the Low Countries with several minor trough lines. Temperature at 500 hPa was around -30C. Due to diurnal heating (lines of) showers were formed, some of them accompanied with a few rumbles of thunder and/or small hail (diameter around 0,5 cm). This report describes the passage of an isolated cell behind a minor through line. Besides one rumble of thunder and small hail, it contained also supplementary feature "mammatus". All pics taken at Kampenhout in local time (CET). 


Radar sequence between 1620-1900 CET. My location was near "BR". The black arrow points to the shower that is described below. Precipitation tops went up to 6 km. (Source radar picture: Belgocontrol)


Satellite picture (visual) of 01/05/2008 at 1755 LT. The red arrow points to the described shower, my location at the red "K". (Source satpicture: NOAA and University of Bern)


01/05/2008 1750 WSW. Incoming shower with a lowered cloud base. This almost precipitation free area  is containing the updraft, with on its right side the downdraft area containing a shaft of rain & small hail.


01/05/2008 1800 WSW. Precipitation area is almost overhead.


01/05/2008 1739-1809 WSW. Motion picture of the weather elements during 30 minutes shortened to a time-lapse of 28 seconds. Shear is quite obvious in this shot, leading to a rather active part of the up- & downdraft area.


01/05/2008 1820 E. Two pictures are horizontally stitched in this panoramic view of the backside of this shower with a pronounced primary rainbow and faint secondary rainbow.


01/05/2008 1825 NE. Two pictures are vertical stitched in this panoramic view of the Cb showing the hairy upper portion (capillatus). Precipitation on the extreme left side starts to diminish.


01/05/2008 1829 NE. Two pictures are horizontally stitched in this panoramic view of the entire single cell. Weak mamma features can be recognized in the upper left part. The right side (updraft) is still relative young and active with also "praecipiatio". After 40 minutes this cell did vanish completely.


01/05/2008 1824-1842 NE. Motion picture of 18 minutes shortened to a time-lapse of 18 seconds. The backside of this cell shows the decaying process as updraft is halted. Ultimate some mamma features appeared.


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