The location and strength of Convergence cloud Lines is strongly influenced by a number of parameters:

Direction and Magnitude of the low-level wind

When the wind direction is parallel to the axis of the bay, or when there is light wind, cloud lines will develop in the centre of the lake or bay.
If the wind direction is at an an angle to the axis of the bay, the line will be shifted towards that coastline at which the wind-direction is orientated towards. For development of cloud lines in the Gulf of Finland, surface winds are generally above 10 m/s (Andersson and Nilsson 1990). Note the convergent wind field in the area of the Skaggerrak.

Fetch

The distance that the air parcel travelled over the water, is dependant on instability and the intensity of the Convergence cloud Lines. Because of the initially stable character of the continental air, the clouds develop at some distance offshore. The distance between the point where the lines develop and the point where the air is travelling off-shore, is dependent on the windspeed and instability of the airmass.

Temperature Difference between water surface and the air

Because of the temperature difference between land and water, an atmospheric circulation develops. Fluxes of sensible and latent heat from the warmer water lead to a boundary layer that is very unstable, leading to shallow, moist convection. Studies of the Gulf of Finland show that the temperature difference between land and water was on this occasion at least 8°C. There is a large temperature difference between the air and sea temperatures. Sea temperatures are varying between 9 - 11°C. Air temperatures are significantly lower: 0 - 3°C. This is an important factor in establishing a mesoscale atmospheric circulation. Due to the large temperature difference, offshore winds are generated which results in convergence in the centre of the Skaggerak.

Low level Convergence and vertical motion

The numerical model indicates low level convergence in the area of the cloudband.
As a result of the low-level convergence, there is vertical motion in the lower levels of the troposphere.