Author Topic: pronounced sqall line 2007 + footage  (Read 3071 times)

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pronounced sqall line 2007 + footage
« on: 12 September 2008, 10:24:24 AM »
maybe someone is interested ...

i would like to discuss the formation and passage of a pronounced sqall line over eastern Austria in June 2007.....

21 June 2007 was a hot summer day in Austria, with temperatures in the mid 30`s during the afternoon.

the synoptic situation shows a pronounced trough over the eastern Atlantic resulting in a pronounced warm southwesterly flow over the eastern alps. a weak cold front was approaching from the west and supposed to pass the region during the evening.

The Vienna sounding showed very promising conditions for the development of severe convection

Around 10 UTC convection was triggered along the weak cold front in Bavaria

(i`m sorry for the arrows, but the pictures were taken from a discussion paper for stormchasers)

about an hour later there was a fully developed line echo

..turning rapidly into a pronounced bow echo (.. white pixels eqal a reflectivity of 60 dBz and more)

Later , the system started to weaken, but the outflow triggered another storm ahead of the line ..

.. which again rapidly turned into a bow echo

now the systems changes more into a line echo wave pattern, the southernmost cell develops some supercell-like features (sharp gradient ..)

on the northern edge of the southernmost system a bookend vortex develops

The LEWP caused damage because of large hail up to 6cm in diameter, especially on the southern edge, damaging winds up to 150 km/h as well as flooding. Unfortunately 3 people lost their lives in Vienna, due to windthrown trees and a destroyed crane.

The fully developed system caused a very pronounced pressure wave leading to gale force gusts.

Also satellite imagery gives a good overlook on this impressive system:

Overshooting tops

and here is some footage by myself, as i was lucky enough to have my camera with me as the storm passed the place where i used to work.

(approach - gusts - rain - hail -- and more hail)

regards, Manfred

« Last Edit: 12 September 2008, 10:36:00 AM by phix »