Zeus

.... stopped her mill and said, a sign for the king:"Father Zeus, who rules over gods and men, you have thundered from a starry sky where there is no cloud anywhere. Surely this is a wonder.

Zeus 'answered' immediatly and the woman who is grinding barley ....

Odyssey Book 20 line 96-98 Barry B Powell
Odyssey Book 20 line 100-103 Barry B Powell
Odyssey Book 20 line 103-105 Barry B Powell

Zeus

I have spend months on the island of Lefkada to witness small earthquake several times. And everytime such a event occurs there is a rumble, like thunder, 1 or 2 seconds before the real earthquake is felt. It must have been the thunder from the starry and cloudless sky.
The woman continues:

May the suitors take their pleasant feast in the halls of Odysseus for the very last time on this day -they who have loosened my limbs with bitter labor as I grind the barley. May they now dine there last.

Grinding stone found in the palace

Father Zeus, if you gods have willingly brought me over land and sea to my country, after you had tormented me exceedingly, let someone of those who are awaking utter a word of good omen inside the house, and may some other wonder appear from Zeus outside. So he said in prayer, and Zeus the couselor heard him. Immediately he thundered from gleaming Olympos, from the high clouds, and the good Odysseus rejoiced.

Odysseus prays to the gods:

Well, as you know by now, I am not a believer in gods or wonders or something, so this must have been something else.