Probabilistic Forecasts for the Big Thompson River & tributary

By March 22nd, probabilistic forecast graphics will be available for the North Fork Big Thompson River at Drake and Lake Estes inflow on the Denver/Boulder Advanced Hydrologic Prediction Service (AHPS) website. AHPS is the modernization of hydrologic forecasting to improve flood forecasts and water resources information. 


Locations can be accessed from the interactive map (the sites with probabilistic forecasts have circle icons) or the pull-down menu below the map.  For sites with probabilistic forecasts, click on the tabs above the hydrograph to view weekly and entire period chance of exceedance graphics or “how high will the river rise.”


The entire period graph displays the chances (1 to 99 percent) of the river exceeding a certain level during the outlook period. The weekly extended outlook graph provides information about chances or probabilities of exceeding certain levels, flow, and volume during each week for an individual point. For a description of these plots; click the icon (about this graph) below the probabilistic graph.


In addition to the graphical information, a text version will be issued near the end of each month with probabilistic forecasts for these and currently existing probabilistic sites.


If you have questions, please contact the National Weather Service Office in Denver/Boulder at (303) 494-4221 or e-mail the webmaster.

Return to News Archive is the U.S. government's official web portal to all federal, state and local government web resources and services.