Phased Array Radar: Applications to Land Falling Tropical Cyclones

NSSL scientists recently reported on the unusual opportunity to scan a tropical cyclone with an experimental radar located far from the coast. Using the National Weather Radar Testbed Phased Array Radar (NWRT PAR) in Norman, Oklahoma, scientists captured images of Tropical Storm Erin as the unusual weather event stalled over the state.

Tropical Storm Erin formed in the western Gulf of Mexico as Tropical Depression Five on August 14, 2007. It was upgraded to a Tropical Storm the morning of August 15. Erin moved onshore near Lamar, Texas on August 16 and weakened to a Tropical Depression. The center of the circulation moved north and entered southwest Oklahoma late August 18. The Tropical Depression became much better organized by August 19 as it approached Oklahoma City and the NWRT.

The PAR was able to complete scans of T.S. Erin at rates between 30-43 seconds, compared to the WSR-88D radar’s 4.1 minutes.

Scientists reported the potential benefits of PAR in scanning land falling tropical cyclones are:
- The capability to focus data collection
- Higher user confidence in location, intensity and movement of
- More regionally specific warnings
- Increased lead-time for tornado warnings
- With dual-polarization capability there could be improved rainfall estimation

Significance: Earlier detection of hazardous severe weather using PAR has strong potential to aid forecasters in providing more accurate and timely warnings of high-impact weather events that disrupt economic productivity and cause loss of life and property.