security design question

I have a site where users can log in, and on the login screen there is a "Remember Me" checkbox. If the user checks it, their email will be written as a cookie and next time the user hits a page where they need to log in, I have a function that checks for the cookie value, and if it's value exists, logs them into the system with just the email.

My question is this, is it secure enough? The only way validation occurs JUST on the email is when a cookie value is present. Is there any way to "forge" a fake cookie with the correct email address?

I have no problem adding the password value as a cookie, encrypted of course. I'm just curious if this is enough.