Looks like it's finally getting here and available through GRL2 or 3
WSR-88D Dual Polarization Background and Status
NWS Statement of Need 04-004 (Additional Radar Observational Data) identified the NWS need for additional and improved radar data to improve support to severe weather warnings, flood and flash flood warnings, and general forecast services.
The NEXRAD tri-agencies (DOC, DOD, DOT) have determined that adding Dual Polarization capability to the WSR-88D will provide mission benefits that aid in meeting the NWS Government Performance and Results Act. These benefits include improved hail detection for severe thunderstorm warnings, improved rainfall estimation for flood and flash flood warnings, rain/snow discrimination for winter weather warnings and advisories, data retrieval from areas of partial beam blockage to improve services in mountainous terrain, and removal of non-weather artifacts such as birds and ground clutter to improve overall data quality for algorithms and numerical model input.
In the spring of 2003 the National Weather Service (NWS) Office of Science and Technology (OST) tasked the National Severe Storms Laboratory (NSSL) with providing data collection and analysis to support a WSR-88D dual polarization decision briefing to the NEXRAD Program Management Committee (NPMC). The JPOLE (Joint Polarization Experiment) project was designed to evaluate the engineering design and data quality of the polarimetric KOUN WSR-88D radar and demonstrate the utility of polarimetric radar data and products to operational users. (For more information see Overview of the Joint Polarization Experiment (JPOLE) produced by the NSSL.) The NSSL JPOLE experiment demonstrated the performance improvements dual polarization provided in rainfall estimates, hydrometeor classification, and general data quality.
A competitive Firm Fixed Price Contract was awarded to L3 Communications (teamed with Baron Services & Essco) on September 24, 2007 for the upgrade of the WSR-88D Weather Radars with Dual Polarization capability. A Kick-off meeting was held in Norman on October 23, 2007.