| Weather pictures & report of June 9 2009 |
| Multi-cell thunderstorms in maritime unstable airmass. |
| Synopsis: at 500 hPa an approaching relaxing upper trough from the west of which its axis passed Belgium during the evening. Ahead advection of potentially unstable air and due to the diurnal heating from the early afternoon on multi-cell thunderstorms did form in many places. Some of them were aligned according a few minor trough lines. All pictures were made at Steenokkerzeel, hours in local time (CET). |
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Surface analysis of June 9 at 1400 CET. Between two lows, our area is a
SW'ly airflow, later during the evening, the trough line over
northwest France passed Belgium
enhancing the instability. (Source chart: Belgocontrol)
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Upper air analysis 500 hPa of June 9 at 1400 CET. Relaxing upper trough
approaching the Benelux. (Source chart: DWD via wetter3)
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Forecasted sounding of Brussels of June 9 at 1700 CET. The unstable
layer reaches to 300 hPa corresponding with a height of 10 km. (Source:
RASP)
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Forecasted sounding of Maastricht of June 9 at 1700 CET. Same profile
with on the right side some additional thunderstorm indices. (Source: Weeronline)
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09/06/2009 1800-2100 CET. Satellite loop in the visual channel. Approaching trough line which was just ahead the axis of the upper trough, visible as lower clouds west of these showers. The Cb's with arrows have been described with a time-lapse. (Source sat picture: Eumetsat via Sat24.com)
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Radar loop between 1820-2100 CET. Precipitation tops went up to around 10 km. The two cells with arrows have been described with a time-lapse. (Source radar picture: Belgocontrol)
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09/06/2009. Lightning sequence between 1745-1945. (Source:
blids)
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09/06/2009 1821-1846 SSE-SE. Events of 25 minutes shortened to this time
lapse of 27 seconds. Ahead of the trough, this isolated shower eventually produced weak
thunderstorms features. It can be checked with radar and satellite
pictures as pointed with a red arrow.
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09/06/2009 1853 SW. Approaching trough revealing nothing
special.
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09/06/2009 1929 SW. Half an hour later things began to become
interesting.
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09/06/2009 1934 SW. Five minutes later, a nice arcus was on its way.
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09/06/2009 1936 SW. Two minutes later, further shifting eastwards.
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09/06/2009 1940 SSW. Four minutes later, arcus overhead.
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09/06/2009 1921-1946 SW to S. Events of 25 minutes shortened to this
time lapse of 25 seconds. This shower had all the time some weak to
moderate thunderstorm features. On the passage of the arcus, wind picked
up to 30 kt. It can be checked with radar and satellite pictures as
pointed with a yellow arrow.
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09/06/2009 2003 S. One distinctive horizontal discharge, at a distance
of 6 km, could be captured in this rather weak thunderstorm as the rate
of lightning was only once in a
few minutes.
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09/06/2009 2030 SW. After this shower, another one showed up.
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09/06/2009 2047 S. Produced as its predecessor whales mouth
structures.
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