"Red Sky at Morning" refers to an old seafarers saying "Red sky at night, sailor's delight. Red sky at morning, sailor take warning." This saying voiced the belief that when the sky was red in the evening, the weather the following day would be fair. A red sky in the morning, however, was a predictor of bad weather and rough seas.
The Quote today is from Pilot episode.
Dean: Are we talking like "misdemeanour" kinda trouble or "squeal like a pig" trouble?