Weather pictures & report of June 7 2012

 

Multicell & tornadic supercell thunderstorms along cold front.


Synopsis: at 500 hPa, Belgium east of a cut off low in a rather strong SW flow. During the period consecutive passage of warm front, cold front and trough line. Along the cold front some showers did develop in a rather strong shear environment. During the evening, it lead to a supercell storm over the south(east) of province Limbourg with briefly even the touch down of a weak tornado (F1). At my location (center of Belgium), also some chaotic skies could be detected, however the directional shear was somewhat weaker and only some weak multicells could develop. All pictures were taken at Kampenhout (central Belgium), hours in local time (CET). 

 

Surface analysis of June 7 2012 at 2000 CET. Steering feature is a depression centered over Wales. In the SW'ly the associated warm front crossed Belgium in the first part of the day, the cold front followed during the second part. This cold front was in fact positioned on a showery line, see another version below.  (Source chart: Belgocontrol)

 
Surface analysis of June 7 2012 at 1700 CET. Second version of the surface analysis with aid of satellite: the triple point would cross the centre of Belgium, behind a trough line with some scattered showers. This version seems the most close to the things that happened on the field. (Source chart: KNMI)

 
Loop of 7 surface analyses of June 7 2012 (of each hour between 1600 - 2200 CET) with weather plots. (Source: meteocentre.com)

 
Upper air analysis 500 hPa of June 7 2012 at 1400 CET. Cut off low between Ireland - Iceland. A weak mobile ridge crossed Belgium in a strengthening SW flow during the day. The relaxing trough crossed Belgium the next day. (Source chart: DWD via wetter3)

 
Upper air analysis 850 hPa of June 7 2012 at 1400 CET. Recognizable again the cut off low near Ireland, Belgium in a moderate SW flow advecting mild air (10°C). (Source chart: DWD via wetter3)

 
Upper air analysis 850 hPa of June 7 2012 at 1400 CET. Here we take a look at Tw at 850 hPa, with a tongue of warm moist air moving towards the Ardennes with overthere Tw that would reach almost 16°C. (Source chart: Meteocentre.com)

 
Loop of forecasted soundings for Brussels of June 7 2012 between 0830-2000 CET. A large part of the period some low level instability was present till around 3 km height. By the end of the period this instability reached up to 8 km, although much drier air came in. Detect also the rather strong shear (speed and directional). (Source: RASP)

 
Another loop of forecasted soundings for a 12 hours period (in steps of three hours) of Brussels from June 7 2012, 1100 CET onwards. Included are some thunderstorms indices: surface based CAPE went up to almost 700 J/kg, KI 31, TT 50, LI -3 = moderate convective potential which may lead to scattered thunderstorms. The SREH of 120 m²/s², in combi with the not too strong CAPE, the environment would be favorable for multicell thunderstorms. (Source: weatheronline.co.uk)

 
Forecasted vertical profile and surface temperature for Brussels Airport of June 7 from 1400 CET and the following 48 hours. Legend of upper map: green-brown-white is humidity in steps of 10% with darkest green being 90% or more, wind in kt, temperatures each 5°C. From the start humid air well towards the upper levels (200 hPa). Late afternoon drier came in from the highest levels. First six hours also significant shear in direction (and speed). (Source: Belgocontrol)

 
Forecasted precipitation, 2 meter temperature for Brussels Airport of June 7 from 1400 CET and the following 48 hours. Legend: precipitation darkest green = dynamical rain, light green is convective rain. Wind in kt. Dynamical rain started in afternoon ending with convective character towards 1800 UTC. The wind veered remarkable just after 1800 UTC. (Source: Belgocontrol)

 
07/06/2012 1915-2115 CET. Satellite loop in the visual channel. Sharp edged storms are recognizable. (Source sat picture: Eumetsat via Sat24.com)

 
Still satellite picture in the visual channel where over Belgium some deep convection was taking place. (Source: NOAA via University of Bern)

 

Radar loop (rainfall rate in mm/hr) of June 7 2012 between 1600-2230 CET. The precipitation started as dynamical character but ended convective. Around 1700 UTC it resembles over the center as a bow echo, as shown a bit further in the photos and time lapse on the field, there was at that moment a quite turbulent character of the cloudiness present. At 1740 UTC, over Limburg, there was briefly a supercell with hook echo in which a weak tornado was spawned, see also radar picture below. (Source radar picture: Belgocontrol)

 

07/06/2012. Still image of the radar at 1740 UTC (or 1940 CET). The red arrow just north of "LG" shows the signature of a hook echo. (Source picture: Buienradar)

 
07/06/2012 around 1935 N-NW. A glimpse of the weak tornado (F1) just north of Tongeren (in the south of province Limbourg). Source picture: "Yannick" via http://nieuws.meteovista.be)

 
07/06/2012. Track of the tornado on a Google map based on info from witnesses or damage. (Source picture: weerwoord.be)

 
07/06/2012. Amount of discharges over the Benelux which were quite low. (Source picture: Buienradar)

 

Some metars (hours in UTC). Translation: copy paste each obs via metar-decoder

Strong veering wind during the evening at Liège & Maastricht. It did occur also over Brussels, but somewhat later in timing, before that, the wind was somewhat variable.   

Brussels

201206071620 METAR EBBR 071620Z 12005KT 070V150 8000 -SHRA SCT030CB 17/15 Q0998 TEMPO VRB15G35KT 3000 TSRA
SCT025CB=
201206071650 METAR COR EBBR 071650Z 34003KT 310V040 9999 -SHRA FEW013 SCT035CB 16/14 Q0998 TEMPO VRB15G35KT
3000 TSRA=
201206071720 METAR EBBR 071720Z 35004KT 280V030 9999 -RA FEW003 BKN023 16/15 Q0999 RESHRA TEMPO 4000 SHRA=
201206071750 METAR EBBR 071750Z 10005KT 040V150 9999 -SHRA FEW020CB BKN040 16/14 Q0999 TEMPO 4000 SHRA=
201206071820 METAR EBBR 071820Z 14004KT 9999 FEW020CB 17/15 Q0999 NOSIG=
201206071850 METAR EBBR 071850Z 16005KT 9999 FEW030CB 16/14 Q0999 NOSIG=
201206071920 METAR EBBR 071920Z 16006KT 9999 FEW030CB 16/14 Q0999 NOSIG=
201206071950 METAR EBBR 071950Z 25011KT 220V290 9999 FEW030CB SCT042 17/15 Q1001 NOSIG=
201206072020 METAR EBBR 072020Z 26008KT 9999 FEW030 SCT048 15/12 Q1001 NOSIG=
201206072050 METAR EBBR 072050Z 24007KT CAVOK 15/12 Q1001 NOSIG=
201206072120 METAR EBBR 072120Z 22006KT CAVOK 13/12 Q1002 NOSIG=
201206072150 METAR EBBR 072150Z 19004KT 9999 FEW047 13/11 Q1002 NOSIG=

 

Liège

201206071550 METAR EBLG 071550Z 12006KT CAVOK 20/12 Q0999 NOSIG=
201206071620 METAR EBLG 071620Z 12008KT CAVOK 20/13 Q0998 TEMPO 4000 SHRA=
201206071650 METAR EBLG 071650Z 15008KT 9999 -RA SCT017 20/15 Q0998 TEMPO 4000 SHRA=
201206071720 METAR EBLG 071720Z 17013G25KT 140V210 9999 -RA SCT034 20/15 Q0998 TEMPO 19015G27KT=
201206071750 METAR EBLG 071750Z 20020G32KT 9999 BKN032 21/15 Q0999 TEMPO 19015G27KT=
201206071820 METAR EBLG 071820Z 23018KT 9999 SCT032 20/15 Q0999 TEMPO 19015G27KT=
201206071850 METAR EBLG 071850Z 24014KT 9999 FEW032 20/14 Q1000 NOSIG=
201206071920 METAR EBLG 071920Z 24011KT 9999 FEW032 19/14 Q1001 NOSIG=

 

Maastricht

201206071525 METAR EHBK 071525Z AUTO 18008KT 150V210 9999 NSC 21/13 Q1000 NOSIG=
201206071555 METAR EHBK 071555Z AUTO 14005KT 100V180 9999 NSC 21/13 Q1000 NOSIG=
201206071625 METAR EHBK 071625Z AUTO 11006KT 080V140 9999 NSC 20/14 Q0999 NOSIG=
201206071655 METAR EHBK 071655Z AUTO 08006KT 050V110 9999 DZ FEW014 BKN022CB 20/15 Q0998 NOSIG=
201206071725 METAR EHBK 071725Z AUTO 13008KT 100V160 9999 -RA FEW019CB SCT035 19/15 Q0998 NOSIG=
201206071755 METAR EHBK 071755Z AUTO 12007KT 9999 -RA FEW008 BKN015CB BKN034 BKN038 18/16 Q0998 REDZ TEMPO
TSRA=
201206071825 METAR EHBK 071825Z AUTO 25011G21KT 200V330 9999 SCT015CB SCT021 BKN030 BKN035 18/16 Q0998 TEMPO 25016G26KT BECMG 22012=
201206071855 METAR EHBK 071855Z AUTO 26007KT 200V300 9999 FEW029 18/16 Q0999 NOSIG=
201206071925 METAR EHBK 071925Z AUTO 25007KT 210V300 9999 SCT020 BKN024 BKN028 18/16 Q1000 NOSIG=


Below some picture taken at Kampenhout

07/06/2012 1927 SSW. Some chaotic skies began to appear.

 
07/06/2012 1932 SE. A strange looking low cloud was of interest.

 
07/06/2012 1932 SE. Zooming in, the bottom part moved to the right of this picture, while the upper part moved in opposite direction. Could this be the start of a wall cloud with more?

 
07/06/2012 1933 SE. But then it didn't as gradually it became detached from the cloudiness above it

 
07/06/2012 1934 SE. As evident in this picture.

 
07/06/2012 1937 NE. Bit more in northeasterly direction, another strange shaped low cloud began to appear: it resembles a bit to a chicken.

 
07/06/2012 1938 NE. But a bit later, it seemed more to be a turtle. Again here this cloud was boiling in every direction.

 
07/06/2012 1940 W. Driving a bit further, another very low cloud band was approaching.

 
07/06/2012 1943 SSW. Passing overhead.

 
07/06/2012 1950 NE. Opposite direction.

 
Between 1926-1946, direction N, these events were also captured in a time lapse where clearly the turbulent character of the cloudiness is visible.

 
07/06/2012 2149 SE. Later a line of weak showers by with behind a fantastic primary red rainbow.

 

Back to summer reports 2012

Home