Large wildfires may grow for weeks or months from ignition until extinction. Simulating events with coupled numerical weather prediction (NWP)-wildland fire models is a challenge because NWP model errors grow with time. A new simulation paradigm was tested. Coupled Atmosphere-Wildland Fire Environment model simulations of the 2012 Little Bear Fire in New Mexico were implemented for multiple days of fire growth from ignition, then used spatially refined (375 m) 12h satellite active fire data derived from the Visible Infrared Imaging Radiometer Suite (VIIRS) to initialize a fire in progress. The simulations represented fire growth well for 12-24 h after each initialization in comparison to later satellite passes but strayed from mapped area with time.  A cycling approach, in which successive VIIRS perimeters were used to initialize fire location for the next 12 h period, overcame this and can be used with cycled weather forecasts to predict even a long-lived fire's lifecycle.

Fig. 1 The first 9 VIIRS active fire detection polygons during the 2012 Little Bear Fire and the perimeter mapped by USDA Forest Service NIROPs (white line) at 11:10 P.M. MDT on 11 June (12 June, 05:10 UTC). Colors indicate detected fire extent at different overpass dates and times (UTC) (see color bar).

Figure 2. The VIIRS fire perimeter (yellow line) used for initializing fire location in EXPTA. The total heat flux (kW m
2) (color bar) shows modeled fire extent 12 h later, along with coincident VIIRS data (red line), modeled winds at 21 m above- ground level, and modeled smoke mixing ratio (white).