I wouldn't count on spells to keep me safe in a storm, get somewhere safe. There are some precautionary measures I would take. I don't know of any spells to directly protect you from weather but try the triple goddess protection chant. It goes like this "By the dragons light, on this (month) night,
I call to thee to give me your might,
by the power of three, I conjure thee,
to protect all that, surrounds me, so mote it be!". You could also try some sigils, and ask good spirits to protect you.