Stamina day. 2 mile warmup, 4 tempo miles @ 7:30 target (10KGP), 1 cooldown mile. Thought it would be tougher as I haven't done 4 miles @ tempo before but it was fine. Splits were 8:28, 8:33, 7:28, 7:17, 7:17, 7:00, 7:47. 7:15 average for the tempo, 7:41 for the whole run. I didn't notice I had a chance to break 7 in the last mile until there was only .05 left so I took off but it was too late to get it. Also, it was unplanned, but I ended up doing the cooldown @ HMGP to simulate mile 10 or 11 of the half.
So, yeah, the pace was faster in my 4 mile tempo today than in my 5k race...what a dummy. Today the wind was from the south @ 15mph. So I paid close attention to the pace on each leg around my university loops and tried to maintain an even effort. Going south I was running 7:45s and going north 6:55s. The crosswind legs were about 7:10. So, doing the math I came up with an approximation of the effect of wind on distance running. Looks like +2 sec/mile for every 1 mph of direct headwind, and -1 sec/mile for every 1 mph of direct tailwind. So for example, if you're running directly into a 10mph head wind, your pace will be 20 sec/mile slower. Let me know what y'all think of the accuracy of that with your experience. My guess is that there is not an exact linear relationship like that formula would imply; it's probably somewhat exponential, similar to a gas mileage curve which shows you getting dramatically worse gas mileage after 50 mph or so. But my brain isn't big enough to work that into a formula for running.
Applying that linear relationship to my Saturday disaster, my first mile would've been in the 6:20-6:30 range with no wind, probably close to a 1-mile PR for me. Makes sense that I was unable to move it for the last 2 miles of the race. Now that I feel like a complete nerd, I'll end the entry. | 
