Purpose

This is a page containing the WarnGen Zone based inclusion fraction, specific to the settings for SPS,  for all CWAs that focal points can use to explore in order to decide how or if to modify their office's values when transitioning to Hazard Services Convective. 

If you have questions or feedback about this table you can contact the AWIPS team via email: nws.wdtd.awips@noaa.gov 

What Is A Zone Inclusion Fraction?

This is a value (either in % of zone area and/or square kilometers of zone area) that determines the amount of space a polygon needs to cover in order to trigger hatching and include the zone in the warning or statement. This page will only cover the settings specific to the Severe Weather Statement (SPS) which uses zone based inclusion fractions (as opposed to other county based warnings and statements, which would use the county inclusion fractions, details on which can be found here. 

Changing Your Zone Inclusion Fraction for SPS

In WarnGen, the SPS uses the Zone areaSource tag within the geospatialConfig_ZONE.xml file. 

Edit the appropriate values (inclusionPercent, inclusionAndOr, and inclusionArea) to adjust your settings.

Zone Inclusion Fractions Across The NWS

16 sites do not have the settings for Zone Inclusion Fractions configured: CYS, DVN, EKA, EPZ, GGW, GUM, HNX, ILX, LKM, MSO, PUB, SGX, SJU, STO, TFX, and VEF. 

22 sites use the default settings of 0% AND 0 sq km.

The majority of sites have percentage inclusion values ranging from 1-5% with varying use of AND/OR and a range of area inclusion values.  45 sites have set their area inclusion to 0 sq km while 28 sites have values greater than or equal to 20 sq km.