| Summary: | Data analysis of SYNOP observations was made for investigation of stratus formation in rain. The aim was to find connections between meteorological parameters in the different states of rain to develop a forecast method. 1594 cases of rainfall from the four stations Luleå, Uppsala, Linköping and Såtenäs, Sweden were analysed, 974 cases include stratus formation in rain and the other 620 cases are without stratus formation. The investigation focused on the meteorological parameters wind direction, wind speed, relative humidity, visibility, cloud base height and rain intensity. As rain intensity was not explicitly included in the SYNOP observations it could not be taken as a governing parameter, but classification of the data into four groups of different rain intensity was possible. Also time was a parameter for the investigation. The results show that a more detailed investigation should be made to eliminate several influences of other parameters, for example of radiation or soil conditions. Thus it was too difficult to develop a forecast method for the formation of stratus in rain, but suggestions for further investigations and the development of a numerical model only are made. En dataanalys av SYNOP-observationer genomfördes för undersökning av stratusbildning i regn. Målet var att hitta samband mellan de meteorologiska parametrarna i olika regntillstånden för att utveckla en prognosmetod. 1594 regntillfällen från fyra stationer, Luleå, Uppsala, Linköping och Såtenäs, analyserades. 974 tillfällen innehåller stratusbildning i regn och de andra 620 tillfällena visar ingen stratusbildning. Undersökningen koncentrerades på de meteorologiska parametrarna vindriktning, vindhastighet, relativ fuktighet, sikt, molnhöjd och regnintensitet. Eftersom regnintensiteten inte var beskriven i SYNOP-observationer kunde den inte tas med som parameter i analysena. Det gick att indela datan i fyra grupper med olika regnintensitet. Tid var också en parameter i den här unders- ökningen. Resultater visar att det behövs en ...
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