Lawrence Livermore National Laboratory



In order to support emergency response applications, NARAC acquires and maintains global databases of current and forecast weather data. This consists of meteorological observations as well as numerical weather prediction model forecasts and analyses. Appropriate sources of meteorological data are selected based on on the time period of the simulation and the availability of representative data.

Real-Time Meteorological Data

NARAC obtains real-time meteorological observations from a variety of sources. Hourly surface and twice-daily upper-air meteorological data are acquired via redundant communications links to the U.S. Air Force Weather Agency (AFWA) and the National Oceanic and Atmospheric Administration (NOAA). Additional data is acquired from NOAA's profiler network and regional networks (mesonets), NARAC-supported site towers, and commercial sources. In 2012, NARAC acquired observational data from over 47,000 sites world-wide.

Numerical Weather Prediction (NWP) Model Output

NARAC utilizes numerical weather prediction (NWP) model forecasts and analyses as appropriate for the area and time of an incident. Global and regional-scale model output are provided by multiple agencies, including the National Oceanic and Atmospheric Administration (NOAA) / National Center for Environmental Prediction (NCEP), the US Navy Fleet Numerical Meteorological and Oceanographic Center (FNMOC), and the US Air Force Weather Agency. Examples of NWP data available from these sources are:

  • NOAA / NCEP global and regional forecasts and analyses
    • North American Model (NAM), currently using the Weather Research and Forecast (WRF) model
    • Global Forecast System (GFS)
    • Rapid Refresh (RAP) forecast model initialized using analysis/data assimilation
  • Air Force Weather Agency (AFWA) Weather Research and Forecast (WRF) model output
  • FNMOC Global NAVy Global Environmental Model (NAVGEM) output

NARAC regularly upgrades and replaces these data as the providers update their feeds with higher resolution output (e.g., NAM, GFS, RAP/HRRR upgrades) or new models (e.g., AFWA's potential adoption of a U.K. Met Office model).

In addition, NARAC runs its own in-house version of the community Weather Research and Forecasting model (WRF) to develop high-resolution forecasts and analyses for areas of interest.

Examples of Numerical Weather Prediction Model Output from External Sources (2014)
Agency Model Resolution/Coverage
Air Force Weather Agency (AFWA) WRF 45 and 15 km resolution, special regional forecasts
Fleet Numerical Meteorology and Oceanography Center (FNMOC) NAVGEM Global coverage, 0.5° (~50 km) resolution, output at 3 hr intervals for 72 hrs, updated at 0000 and 1200 UTC daily
NOAA National Weather Service (NWS) GFS Global coverage, 0.5° (~50 km) resolution, output at 3 hr intervals for 240 hrs and at 12 hour intervals out to 384 hrs, updated 4 times per day
NAM (WRF) North America coverage, 12 km resolution, hourly output for 36 hrs and at 3 hr intervals out to 84 hrs, updated 4 times per day
RAP 13 km resolution, U.S. Coverage, hourly output for 18 hours
NARAC In-House NWP Capabilities WRF Global coverage, variable resolution and output intervals