As Mizinamo pointed out above, the second verb is a subjunctive, which it might be in English as well. In the third person singular, though, it's the same as the indicative, as it is in English. I think you probably could translate this subjunctive phrase with an English future, but the preferred answer shown above is "I hope the weather is good," which also works.
I think the most impersonal way to phrase "hopefully" would be something like "Ας ελπίσουμε" (literally meaning "Let us hope"), since a proper adverb doesn't exist in Greek. Some more liberal expressions with a similar meaning would be "Αν όλα πάνε καλά", "Καλώς εχόντων των πραγμάτων" (literally meaning "If all goes well"). :)