Not unusual to have tropo this time of the year. Warm days and cool nights are plentiful in the spring and fall. Add in the increased differential of the coast and water temperatures. And pay attention to severe weather fronts crossing your location. Same idea: the temperature difference creates a "mirror."
Find a weather mapping program for your computer or tablet or phone that shows fronts and temperatures. For Android "Windy" and "MyRadar" work for me. (I don't know if these are available for iOS.)