Oscar Plange <oscar> writes:

EVENT International Hang Gliding Challenge

Location Groblershoop, Northern Cape Province, South Africa

Venue Thuru Lodge

http://www.kalaharibigskychallenge.co.za/2014KBSCInvite.pdf

Please indicate by end of April 2014;

• Number of pilots interested

The major weather engine for the Southern African region is a strong high
pressure system over the Atlantic Ocean, which periodically sweeps around the
country to link up with a high pressure system over the Indian Ocean. The
outstanding, and for soaring, most important feature in this "concert of air
masses" is the formation of a heat low over the interior of Southern Africa
during the summer months. Due to its elongated shape (NW to SE) this is
frequently referred to as the "trough line". Subsiding air just West of the
trough line forms an inversion – so vitally important for successful soaring
flights. This subdues the thunderstorm activity and together with the now
significantly dryer air (dew points between 3 and 7 degrees Celsius), leads to
the formation of flat cumulus clouds with a cloud base of between 14.000 and
18.000 ft MSL as well as strong thermal activity - a glider pilot's dream.
Groblershoop generally lies just West of the trough line, where over-development
is unlikely. Wind direction in this area of lift varies from Northerly through
to Westerly.