> 150% of Average
130% - 150% of Average
110% - 130% of Average
90% - 110% of Average
70% - 90% of Average
50% - 70% of Average
< 50 % of Average
No Average
No Forecast Available
About Water Supply Map
The NWS issues forecasts for seasonal snow melt streamflow volumes in the western US. Forecasts are typically issued monthly between January and July. They combine information from current mountain snow pack states with soil moisture and weather and water forecasts through a hydrologic and snow modeling system at River Forecast Centers.. Forecasts are coordinated with other agencies in many locations. Individual forecasts are accessible by following the link on the pop up box that appears when you click on a point.