No momentum today?
Set a timer. Write as much as you can in 15 seconds. Nonsense sentences, overheard conversations, it doesn’t matter. Go off with thunder and lighting for just 15 seconds. Set a goal, like filling an entire page or race against yourself for word number count.
Chances are, you’ll want to keep writing longer than that once you’ve found something that strikes your interest. (Hope you appreciate the bonus pun.)