Man in Tights
I usually run HMs below 1:40.
I've registered for a 10K which is a month and a half from now. Based on current pace I cover this distance in 47 minutes. My best, a couple of years ago, was 44:08.
What is a realistic target and how should I train for it given that I have little more than a month left?
I think you should be able to run 45:00 or slightly faster. Not much time left to specifically train but I like that you're doing a tempo run about once/week but I don't like that the tempo pace is not much faster than what you label as 'easy' runs. Either ease up on the easy runs or step it up on the tempo runs. Maybe shorter tempos at 7:15 pace rather than your current ~7:40 pace. Other than that just keep doing what you're doing at minimum, maybe try to increase your mileage a bit.
I agree with the 45 minute estimate, that seems more consistent with your pace at the half marathon distance.
I am puzzled that your average training pace seems very quick, under 5:00 per km. This seems very fast, close to 10k race pace.
PBs since age 60: 5k- 24:36, 10k - 47:17. Half Marathon- 1:42:41.
10 miles (unofficial) 1:16:44.