United States tropical cyclone rainfall climatology

Below is a list of the top ten highest known storm total rainfall amounts from individual tropical cyclones across the United States since 1950.

The impact of tropical cyclones and their remnants originally from the eastern Pacific stretches as far east as Michigan and Indiana.

Rainfall related to the low pressure area once associated with a tropical cyclone, or its remnants aloft, are included in this sample.

[2] To the right is a graphic showing averages and extremes for a 15-year sample of tropical cyclones and their remnants affecting the contiguous United States.

[5] This rule works as long as a tropical cyclone is moving and only the first order or synoptic station network (with observations spaced about 60 mi (97 km) apart) are used to derive storm totals.

Rusty Pfost, now the head of the Miami National Weather Service Forecast Office, did a study in 1999 reviewing rainfall totals from tropical systems affecting Florida between 1960 and 1998.

He found that for tropical cyclones moving at greater than 6 knots, the average storm total was normally in the 5–10 inch (127–254 mm) range.

[5] David Roth, a forecaster at the Hydrometeorological Prediction Center, determined that the average amount for all tropical cyclones impacting the United States was 13.34 in (339 mm) between 1991 and 2005.

Operationally, variations to these amounts are introduced if the cyclone encounters mountain zones, interacts with a nearby front, or the storm is significantly sheared.