The Weather Prediction Center (WPC) is a division of NOAA and the National Weather Service, which has several teams of forecasters that are tasked with predicting the potential for flash flooding and winter weather. Since WarnUS retrieves and displays flash flood warning data, the only WPC product that is displayed is the Excessive Rainfall Outlook (ERO). This is essentially a prediction for where flash flooding is possible and how widespread the flash flooding will be. The outlook categories are described below.


Marginal Risk (MRGL): Isolated flash flooding is possible within this risk area. Any excessive rainfall that does occur is expected to be localized.

Slight Risk (SLGT): Scattered flash flooding is possible within the risk area. Several flash floods are likely to occur, one or two of which may be "significant".

Moderate Risk (MDT): Widespread flash flooding is likely within the risk area. Numerous flash floods are likely to occur, and several flash floods are likely to be "significant".

High Risk (HIGH): Widespread flash flooding is expected within the risk area. Numerous flash floods are expected, and any flash flooding that does is occur is likely to be life-threatening and destructive.


More detailed information about WPC excessive rainfall outlooks can be found here.