National Weather Service United States Department of Commerce

Back-to-Back Pacific Storms to Impact the West Coast; Heavy Snow in the Central Appalachians

Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >

Flash Flood Guidance

 

Flash Flood Guidance is an estimate of the amount of rainfall required over a given area during a given duration to cause small streams to flood. These estimates are based on the current soil moisture and stream flow conditions for the area. Flash Flood Guidance is routinely issued by National Weather Service (NWS) River Forecast Centers, and is used by NWS Weather Forecast Offices when issuing Flash Flood Watches and Warnings to the public. Note: Less rainfall is required to produce flash flooding in urban areas.

 

 


 


 

One-Hour Flash Flood Guidance


 

Latest 1-hour Flash Flood Guidance Graphic.

 

 

Three-Hour Flash Flood Guidance


 

Latest 3-hour Flash Flood Guidance Graphic.

 

 

Six-Hour Flash Flood Guidance


 

Latest 6-hour Flash Flood Guidance Graphic.

 

 


Headwater Guidance Text Product

 

Headwater Guidance

The Flash Flood Guidance Text Products (BOSFFGMA, BOSFFGME and BOSFFGNY) were discontinued on April 1, 2019.