Linear Pulse-like Storm: whalesmouth and blowing dust

On August 5th, halfway te afternoon, storms fired over the southern Carpathian mountains (near Brasov). With a southerly flow the storms were advected to the Transsylvanian basin where they tapped into a more moist and unstable airmass. There the storms rapidly arranged in a linear storm system.



The sounding of Bucurest was (in this case) representative for the airmass and windprofile of the area where the storms developed. Fairly large instability (CAPE over 1800 J/kg) and moderate vertical windshear. This explains the further development of the line of storms, which can be seen in the following radar-images:


17:20 lt


17:50 lt


18:20 lt













The storms were moving with a speed of approximately 60 km/hr to the north-northwest. In the middle radar-image perhaps a shortlived small bow is visible. From that time, the line rapidly desintegrated due to the imbalance between CAPE and SHEAR.
Although linear, this storm behaved like a so called pulse storm, which can briefly cause severe weather. The vertical windshear was too low to support a storm-system with well defined separate up- and downdrafts. Also due to the strong outflow, the gustfront moved away from the the line of storms. With stronger windshear the gustfront remains close to the storms. Only then deep convection can organize and develop into a self-sustained long-lived storm-system.

Nonetheless, when the storms reached the Tirgu Mures area, spectacular skies appeared in southeasterly direction:


Out of the hazy layers a sort of battleship appeared.


I was expecting a shelfcloud, instead a large whalesmouth rapidly moved over my position. Notice the large curved front-edge of the whalesmouth.







Perhaps here a small shelf is visible?
















The wind is getting stronger, also some small funnel-look-alikes are visible on the front-edge where inflow meets outflow. Sometimes they become longer and small scuds are moving upward beneath. They aren't rotating and after ten of twenty seconds they disappear.



Dust is kicked up by the strong winds. On the picture one can see tree-crowns are blown nearly horizontal.















Skies are changing with every second that passes. Also there are white holes in the turbulent sky: high contrast, so rather difficult to photograph.


Best skies are in the north now, so I go to our street where horses show up out of the blowing dust....




Hmmm, this one is already halfway the distance cloud-earth. The border between inflow and outflow is where things got interesting today.....


















At last a satelite image of 18:15 local time. For an animation of the images click HERE