BBM
The historical weather data from 3 different weather stations surrounding Ennis show no precipitation on Saturday- daytime or night, on January 5th.
Campbell-Corsicana Municipal, TX History | Weather Underground
I have also attached images of rainfall totals for the US covering that Saturday and Sunday Jan. 5 and 6th, 7AM - 7AM. The 7AM time is confusing, but the maps of the two days do span Saturday night. No measurable precipitation is seen near Ennis on either map.
Total 24-Hour Precipitation
Also 24 hr weather radar does not show precipitation in Ennis on January 5th.
Image Archive
Some of the better weather tools appear down due to the gov shutdown.
Was there really "bad weather" as noted? Were they remembering Saturday night accurately, since they probably weren't thinking of a car in a creek early on? I'm confused.
It only matters because if there really was a driving rain night, the likelihood of Emily not seeing the signs or flooded bridge go way up. It is was dry, then...