I finally had a decent session yesterday too.
2 miles up
3 miles at tempo pace (16:25)
3:00 passive rest
2 miles at tempo pace (11:05)
2:00 passive rest
1 mile at tempo pace (5:28)
2 miles down
On the one hand, averaging around 5:30 pace puts me about 8 seconds per mile slower than when I ran a similar workout last October (5k/3k/2k that time), but that workout was in 72 degree temps after a long and hot summer training session as compared to 88 degree temps last night. Also interesting is that workout was about 2-2.5 months before I ran 1:11:04 for a half (a time that I thought was a bit of an underperformance for my fitness), and I am now almost exactly the same distance out from Chicago as I was from that half when I ran that workout.
Then I looked at where I was this winter when I ran a similar workout before aborting my Boston cycle due to injury. I did a 3/3/2 in February about a month before racing a 49:17 15k, and averaged about 5:24 pace there on an 81 degree day.
For yet another point of comparison, I went back and looked at my training cycle for Chicago 2015 when I ran 2:30:52, which should be a better comparison set of workouts since those were done in the summer as well. Many of my tempo sessions then averaged just under 5:20 when I was doing mile repeats, but when doing 2 mile repeats, mid 5:20s were not uncommon. And I was much more workout ready going into that cycle. (I also think I was in 2:28 shape if I had raced smarter that day and had an ideal outcome - the holy grail of marathon running that is never attained, but always sought).
So I have a bit of work to do to improve my fitness between now and October 7th, but this was the first workout that I have done and then compared to past workouts that left me feeling like going sub 2:30 is a realistic goal, even if I know the workout itself shows that I am not quite there yet.