On 9 August 12 UTC the warm and cold frontal bands are well developed.
Cold front extends from the Baltic Staes to east and south-east, while warm front cloudiness extends from Lithuania to southern Scandinavia and further to Norway. Occlusion cloudiness spiral is about to develop over Belarussia.
Geopotential height at 300 Shows the upper level low centre over NW part of Belarussia, with an associated upper level trough still detectable and extending from NW part of Belarussia towards NE.
Jet stream maximum is located at the rear of the cold front cloudiness. Indications for katatype cold front are obvious; Jet stream does not run parallel to cold front.
PVA max can still be found at the left exit region of the Jet streak.
High values of PV (units in mPVU) are approaching the low pressure centre.
High values of Thetae at 500 hPa over the cold front are advected into the occlusion band. This warm tongue exists for several days and marks the location of the typical warm air at the middle and higher levels of the troposphere within the occlusion.
Relative humidity at 700 hPa shows the high humidity within the fronts and the advection of drier air into the centre of the low pressure.
Strong ascending motion is taking place within the cold front and particularly near the occlusion point over the southern Baltic Sea, southern Lithuania and western part of Belarussia.
The high gradient across the cold front marks the location of the cold front at the lower troposphere. A local maximum of Thetae (52 K and above) is located near the occlusion point over the western parts of Lithuania and over the southern Baltic. This seccluded pocket of warm and moist air is rather persistent during the whole process.
Unstable air is found over large areas ahead of the cold front in warm sector (K-Index over 25). Particularly high K-index values (30-35) can be found within the cold front. The air quickly stabilises at the rear of the cold front.
The surface low pressure centre is located in western Lithuania. Note that already at this stage the vertical axis of the low is in upright position (see height of 300 hPa).