Producing 1-km resolution atmospheric forecasts for a prototype gridded National Fire Danger Rating System

A prototype gridded National Fire Danger Rating System (NFDRS) has fuel and other parameters available on a grid of approximately 1-km resolution. To be consistent with these parameters, atmospheric forecasts are desired at a similar resolution with nationwide coverage. A method is described where forecasts from th 32-km resolution National Center for Environmental Predictions's (NCEP) Eta model are interpolated to the 1-km resolution of the prototype NFDRS grid. This technique uses the model's forecast horizontal and vertical gradients, along with a 1-km topography database, to create forecasts that are much more reasonable for some atmospheric variables in complex terrain. The technique is simple enough that it can run quickly over the nationwide grid so that NFDRS forecasts can be made in a timely fashion. Verification statistics from the summer of 1999 will be presented to show that the interpolation technique is modifying the Eta model forecasts in the proper way, especially in areas of complex terrain.