An approaching low pressure system along with a Pacific style cold front will bring a good chance for thunderstorms tomorrow in East Texas. A line of strong to severe storms will push through the area mainly during the morning hours on Sunday. With these storms, comes a chance of severe weather with damaging winds the main threats. An isolated tornado cannot be ruled out, but winds and heavy rain will be most dangerous.
Storms will likely arrive in western locations (Van Zandt, Hopkins, Henderson counties) before sunrise, and then push through East Texas from west to east through the rest of the morning. Thus most of East Texas will see the storms somewhere in the 6-9AM timeframe. Last place to see the storms will be Deep East Texas, and those could last a little into the afternoon hours. After storms clear, expect breezy west winds bringing drier air into the area.
If you have morning plans tomorrow, make sure to check the weather before doing anything as storms will likely be ongoing at that time.