Operational Impacts of Software Note 26 - Change Lowest Boundary Level Parameter For Layered Products

This software modification note was issued on April 28, 2004. It affects the Layer Composite Reflectivity Maximum (LRM) Product, Layer 1, or Low layer. Previously, the bottom of the layer was user defined, while the top of the layer was 24,000 ft. To support national layer composite maps used by the FAA, the bottom of layer, Layer 0, must be set to the next higher kft above radar height. For example, if the radar height is 3600 ft, the Layer 0 value must be set to 4 (4000 ft).

This parameter is changed at the Edit Selectable Product Parameters window.

If the LRM low product has been used routinely with a higher value for Layer 0, the User Selectable Layer Reflectivity Maximum (ULR) product may be an appropriate substitute. The ULR can have a minimum thickness of 1 kft, with altitudes from 0 to 70 kft. The ULR is also a polar gridded product, thus has finer resolution than the LRM. In the following example, the ULR was generated for the 0 to 5 kft layer.

Up to 10 versions of the ULR can be generated each volume scan at the RPG. However, only one version per volume scan is displayable at AWIPS. Only the latest version requested for a particular volume scan is available for display at AWIPS. This is expected to be corrected in a future AWIPS build.