The barn in which the group takes shelter has large gaps in the walls and roof, yet heavy rain nor the powerful wind from the tornado get through. The inside remains as dry and undisturbed as when they entered.
Although the characters would have always been just a few miles from a major water source (and had maps), they somehow couldn't find water. The vegetation showed no such signs of a supposed drought, either.
There is a shot showing a full moon beneath the sun in daylight. Full moons only rise around sunset when the sun and moon are at opposite ends of the sky. When the moon rises with the sun, it is not visible to the naked eye because the sun's light is too bright, and is known as the new moon.
Sasha accidentally slashes Abraham on the arm after dispatching a number of walkers with that knife. Abraham should become sick and die with the walker blood being introduced into his system, but instead he is fine afterwards.