36 
Negative Surges in the Southern Baltic Sea 
Fig. 5.5. a Route of the depression centre from 06 UTC on 5 December to 18 UTC on 6 December, 
pressure pattern and wind field over the Baltic Sea on 6 December 1965, 00 UTC 
5.5. December 1965 
Meteorological situation 
In the early morning of 5 December, moderate 
southerly to southwesterly winds prevailed on 
the southern Baltic Sea coasts. 
At about 06 UTC, a secondary low pressure cen 
tre located at the southwestern edge of a wide 
depression northeast of Scotland formed over 
Wales. This secondary low deepened rapidly as it 
travelled quickly in northeastern direction, cross 
ing southern England, the southern coasts of the 
North Sea, and Denmark. After having slowed 
down temporarily, it reached southern Sweden 
on 6 December at 00 UTC, with 960 hPa meas 
ured in its centre. Slowing down further and 
becoming weaker, the centre arrived at the 
entrance to the Gulf of Finland at 18 UTC and 
continued tracking east as it filled. 
The wind field generated by this pressure system 
resulted in a strong southerly wind of 6-8 Bft 
backing southeast, partly east, which swept 
across the Baltic Sea on 5 December and the 
early hours of 6 December. The occluded front 
reached the water level gauges of the region 
between 8 and 13 UTC on 6 December (the east 
ernmost gauges first). After the occlusion the 
wind veered and became gusty, up to 8-10 Bft. 
Hydrological response of sea level 
The decrease of sea levels began shortly before 
midnight on 6 December and continued until the 
storm veered to slightly onshore directions. The 
minimum was first reached at Kotobrzeg, at 
438 cm, and one hour later at Swinoujscie, which 
recorded a minimum of 430 cm, followed by 
Sassnitz where 412 cm was measured at 
10 UTC. The curve of the level graph was flat at 
the western gauges. The lowest value of about 
408 cm in Warnemünde was recorded at about 
11 UTC. Wismar recorded the minimum value of 
386 cm at about 12 UTC. 
After the storm had veered lightly onshore, sea 
levels began to rise again until they were close to 
mean sea level around midnight on 7 December.