I cannot use the continue clause in this python programme

can anyone see why my continue function won't work, i am trying to get it to take a word, take out the vowels and then print the letters, one on each line

userWord=str(input("Enter a word: "))
userWord=userWord.upper()

for letter in userWord:
    if letter is ("A,E,I,O,U"):
        continue
for letter in(userWord):
    print(letter)