So I am training for a half in May and I am doing my long runs on the weekend however I have signed up in advance for some 5ks that are on the weekends, Sundays. Any advice on how to balance a scheduled long run with doing a 5k race?
What I did in these cases was try and run the additional mileage later in the day. If schedule called for an eight mile run and I did a 5k in the morning I would run 5 additional miles in the afternoon or evening. My training schedule was for a 10K and I added in a 1/2 marathon as one of my training runs (substituted for a 10 mile long run). I also did 5K races and some 8Ks with secondary runs on some of those long run days.
Another method is to swap some days so the races match up with shorter runs. For example, if you have a 3 mile run on the scedule on Friday you do the long run then with your race counting as your shorter distance on Sunday.
I would occasionally swap days of training (tempo run and intervals -my Tuesday, Wednesday days), but preferred keeping weekends mostly on schedule. Fridays were a rest day for me, so races tended to follow a rest day. Saturdays tended to call for a lot of ~6 mile days so I would do an additional 1-3 miles for those days.