Friday will be hot and sunny with a south wind at 10 mph.  Lows tonight will drop to the mid 60s under mostly clear skies.  Our cold front has sped up for Saturday, resulting in slightly less-hot highs! Northern Oklahoma will only climb to the 70s with isolated showers and storms.  Central Oklahoma will climb to the upper 80s and lower 90s. The true cool-down arrives Sunday with highs in the low 80s. Isolated showers are possible Sunday morning. The heat dome returns next week and highs will soar to the mid 90s, just in time for opening day of The Great State Fair of Oklahoma.