ULM Regional Weather Research and Forecast Model

The Weather Research and Forecast (WRF) model is a state-of-the-art atmospheric modeling system developed by several organizations including the National Center for Atmospheric Research, the National Oceanic and Atmospheric Administration, and others. WRF includes two dynamical cores. The one used here is the Advanced Research WRF core which uses fully compressible, non-hydrostatic equations, a staggered Arakawa C-grid in the horizontal, and a terrain-following hydrostatic pressure coordinate in the vertical.

The ULM WRF is initialized at 0000 UTC everyday and is run for three days over a single domain (no nests) covering Louisiana and parts of surrounding states. Initial and boundary conditions are obtained from the North American Mesoscale (NAM) Model. Select options used in these simulations are given in the table below.

Horizontal resolution 4 km
Number of east-west points 139 points
Number of north-south points 141 points
Number of vertical levels 35 levels*
Model top 50 hPa
Time step 20 sec
Microphysics Thompson
Longwave radiation Rapid Radiative Transfer Model for Global
Shortwave radiation Rapid Radiative Transfer Model for Global
Surface layer Monin-Obukhov (Janjic Eta)
Surface physics Unified Noah land-surface model
Boundary layer Mellor-Yamada-Janjic (Eta)
Cumulus parameterization None
*Variable vertical resolution

Current output available here includes 2-m temperatures, most unstable convective available potential energy (CAPE), composite radar reflectivity, outgoing longwave radiation (OLR), and 6-hr accumulated precipitation. All of these plots also include 10-m winds and sea-level pressure (SLP). There is also a separate plot of only SLP and 10-m winds. A plot showing vertical wind shear between 0 and 6 km is available which also includes SLP and wind barbs valid at 10 m (black) and 6 km (gray). Finally, constant pressure plots are available at 300, 500, 700, and 850 hPa. The 300-hPa maps show winds and geopotential heights. The 500-hPa maps show temperature, heights, and winds. Temperature, dew point (white contours), heights (black contours), and winds are provided at 700 and 850 hPa. Additional output may be made available in the future.

NOTICE: The data herein are experimental and intended for research and educational purposes only. The pages herein contain no implied or other guarantees of accuracy or timeliness of data. Please visit your local National Weather Service site for updated weather information. For further information on the ULM WRF, please contact Dr. Ken Leppert II