The mackeral sky is composed of cirrus and cirrocumulus clouds (which resemble scale patterns on a mackeral's back). The mares tails refer to trails of ice crystals blown in streaks from cirrus clouds. These clouds may appear ahead of an approaching storm or frontal system, and can indicate strong winds aloft. If the cirrus and/or cirrocumulus thicken to cirrostratus, altostratus, and then nimbostratus, stormy conditions may be on the way. Strong winds require less sail for navigation in a rough sea. (Source: Weather Lore, Jingles and Proverbs
I think this cloud pattern (most visible at upper left of photo) might be a "mackeral sky." If so, the proverb held true. This was Tuesday's sunset sky. On Wednesday, we had a rainy, windy day in Hopkinsville. We're not complaining about the rain, though, or the other rains that we've received this month. We hope that the water table is returning to normal levels.