According to the Weather Channel hourly forecast for zip code 76177 the following are the chance of rain:
Sat 3pm - 50%
4 to 5pm - 70%
6pm to Sun 2am - 60%
3am to 4am - 50%
5am - 40%
6 to 8 - 30%
9am - 20%
10am to 2pm - 10%
So the first group going out will dry the track for the other 3 heats. And the run order is:
Run 1 / Work 3
XP, BP, BS, DSP, ES, ESP, FM, STC, STX
Run 2 / Work 4
AS, ASP, BSP, KM, FS, SSP, SMF, STS, STU, T, W
Run 3 / Work 1
AM, BM, CM, CS, DM, EP, FP, FSP, GS, GP, HS, STF, X
Run 4/ Work 2
CP, CSP, DP, DS, EM, FSAE, SM, SSM, SS, STR