Five inch or higher amounts only occur about once every 14 to 25 years and are usually associated with a tropical event. The third basin, TIDT2, had a maximum MAP of over 6.50 inches but it did not occur during a tropical event. This is a result of strong storm systems meeting up with the copious moisture from the Gulf of Mexico. A decrease is noted in most of the basins during the winter, mainly due to the decrease in available moisture and in the summer as a result of the localized nature of convection and how MAP is calculated. Very few events with at least one inch MAP occur in the winter with a secondary minimum in the summer while more events occur during the spring and during the hurricane season.
More events occur during the afternoon and evening then any other time of day.
The peak during 1800 to 0000 UTC is related to the additional help that daytime heating gives to the development of rain and thunderstorms. A weaker diurnal tendency exists in all the basins during the winter months when the energy from strong storm systems can compensate for the lack of daytime heating. During the summer months, there are far fewer storm systems to affect the area and rain events are more dependent on daytime heating for initiation. For the most part, the heaviest six-hour MAPs occurred during various times of the day in the different basins. Conclusions Most of the rain events are less than a quarter inch MAP, tend to occur during the transition seasons and during the afternoon and early evening.