Signe Pettersen Melby, b. 1877 in Norway

My great-grandfather Sverre was born out of wedlock in Norway 12.10.1906. I haven't been able to find any information on his mother, Signe Pettersen Melby. Høydalsmo 1906 According to the baptismal record for the parish in which he was born (Høydalsmo, Telemark) she was: - named Signe Pettersen Melby - born 1877 - Had lived in Bergen for the last 5 years - Worked as a 'butikjomfru' (worked in a store). I haven't been able to find her with certainty in the 1900 census, and the State Archives in Bergen couldn't tell me when she moved to Bergen. There were no records of her there. Neither have I been able to find out when she emigrated from Norway. She emigrated to the US sometime after giving birth to Sverre. I don't know exactly when, but I assume it was sometime before WW2. She must have died in the US sometime after the war. An oral tradition tells me she was born somewhere in Nordland (no specific place indicated, but maybe the northern part of Nordland), but I don't know if that's correct. Thanks for any help Greetings Jonas Hove