Parnell was born in Essex and educated at The Ridgeway School and Swindon Technical College.
She then came to the University of St Andrews as a doctoral student, finishing her Ph.D. in theoretical solar physics in 1994.
[3] In 2006, Parnell won the Fowler Prize for Early Achievement in Astronomy and Geophysics of the Royal Astronomical Society for her research on how the Solar corona is heated.
[4] In 2007 she won a Philip Leverhulme Prize for her work on solar physics.
[2] In her three years as a doctoral student at St Andrews, she climbed all 277 peaks then listed as Munros.