Weather Tidbits: Excessive Rainfall Outlook

This Weather Tidbits explores the excessive rainfall outlook. The Weather Prediction Center issues excessive rainfall outlooks for 3 days out with the probability of rainfall exceeding flash flooding guidance within 25 miles or 40 kilometers. The outlook consists of 4 risk categories, marginal, slight, moderate and high. A marginal risk (level 1) with a 5% chance in green involves isolated and localized flash floods possible. A slight risk (level 2) with a 10% chance in yellow deals scattered flash floods possible; along with isolated significant flash floods are possible. A moderate risk (level 3) with a 20% chance in red has numerous flash floods likely; which include numerous significant flash flooding events possible.

A high risk or level 4 with a 50% chance in pink are where widespread flash floods are likely and severe; that involve areas that don’t normally experience flash floods could. Also, lives and property are in greater danger and high risks are only issued within 2 days out. High risk days are only issued 4% of the year or 15 days; but they account for 44% of flood related fatalities and 86% of flood-related damages.

Categories: Weather Tidbits