I believe your rad fans are electric. Your temp goes up because there is no flow of air while the car sits. At about 110C your rad fan kicks in and cools the rad, thence the temp drops. perfectly normal.
1985 190D 2.2l Sold-to Brother-in-law
1996 Mustang 3.8l -"thinks it's a sports car"
1988 Grand Wagoneer - Sold (good home)
1995 Grand Cherokee Ltd -"What was I thinking??!!"