Tropical cyclone rainfall climatology

The presence of mountains/hills near the coast, like across much of Mexico, Haiti, the Dominican Republic, Central America, Madagascar, Réunion, China, and Japan acts to magnify rainfall potential due to forced upslope flow into the mountains.

[1] During the 2005 season, flooding related to slow-moving Hurricane Stan's broad circulation led to 1,662–2,000 deaths.

Father Viñes of Cuba found that some tropical cyclones have their highest rainfall rates in the rear quadrant within a training (non-moving) inflow band.

[3] Normally, as a tropical cyclone intensifies, its heavier rainfall rates become more concentrated around its center.

Over land, outer bands are more active during the heating of the day, which can act to restrict inflow into the center of the cyclone.

[7] The chart to the right was developed by Riehl in 1954 using meteorological equations that assume a gale radius of about 140 miles (230 km), a fairly symmetric cyclone, and does not consider topographic effects or vertical wind shear.

Storms which have moved slowly, or loop, over a succession of days lead to the highest rainfall amounts for several countries.

Riehl calculated that 33.97 inches (863 mm) of rainfall per day can be expected within one-half degree, or 35 miles (56 km), of the center of a mature tropical cyclone.

[11] The stronger the upper trough picking up the tropical cyclone, the more significant the left of track shift in the rainfall distribution tends to be.

This heavy rainfall can lead to landslides, which still cause significant loss of life such as seen during Hurricane Mitch in Central America.

The highest point total was seen during Hurricane Harvey in 2017, when 60.58 inches (1,539 mm) fell in southeast Texas.