On-scene real time fire weather forecasting: A new capability

Using technological advances in meteorological modeling coupled with the increasing power and speed of desktop and laptop personal computers (PCs), a mesoscale forecasting model has been hosted on PC platforms to provide timely local forecasts. This military technology can be tailored to meet the needs of on-scene fire weather forecasters deployed far from their home stations. Data needed to run the forecast model can be transmitted to the deployed forecaster via modem or satellite link such as DirecPC. The forecast model used is Yamada's Higher Order Turbulence Model for Atmospheric Circulations (HOTMAC) which the Army Research Laboratory has adapted for military use by adding data ingest, objective analysis, initialization, and output algorithms. The entire package is named the Battlescale Forecast Model (BFM). The BFM has been hosted on a Pentium II 400MHz desktop PC and a Pentium II 300MHz laptop system. Local meteorological observation data from weather balloons and surface meteorological sensors are supplemented by regional scale model data and standard National Weather Service weather balloon data to initialize the BFM. Current processing time is approximately one hour to produce 12-hour local forecasts at 5 km horizontal resolution (the maximum recommended for fire weather forecasting) over a 300 km x 300 km horizontal grid. The model produces 32 vertical levels of data at each horizontal grid point, with most of the levels located within the boundary layer near the surface. Future capabilities will include decreasing horizontal resolution to 2 km and lower as computing power and speed increases. Model output can be tailored to produce near-surface meteorological forecasts of winds, temperature, moisture, and stability for use in assessing fire behavior, operational risk assessment, and smoke management. Hosting the BFM on a PC or laptop for fire weather use would complement existing fire weather equipment such as the Air Transportable Modular Unit and Remote Environmental Monitoring Systems, which could provide the BFM with valuable on-scene raw weather data to increase model forecast accuracy. The BFM has been run to produce wind, temperature, stability, and moisture simulations for the 1-2 July 1998 Banner Queen-Chariot fire in southern California. BFM output from this event shows the capability to accurately depict forecasts of local fire weather parameters across varied terrain in a timely manner for use by on-scene forecasters and fire fighting decision-makers.