A comparison of radar scans of a severe thunderstorm as displayed on KTLX and the NWRT

Development of low-level convergence and rotation within a severe thunderstorm near Norge, OK (approximately 50 km from PAR) on 25 April 2006. The top left and bottom right panels are consecutive 0.5° elevation scans from KTLX. The panels in between are consecutive 0.5° elevation scans from PAR. There are 213 seconds between KTLX scans and 58 seconds between PAR scans.

Phased-array radar provides early detection of hazards

NOAA’s NSSL researchers have confirmed the Phased-Array Radar (PAR), under evaluation at NSSL, can detect rotation, hail, microbursts and gust fronts well ahead of other radars due to its rapid volume scan capability. During the summer of 2006 the PAR, WSR-88D, and Terminal Doppler Weather Radar (TDWR) scanned four thunderstorm cases in central Oklahoma. NSSL researchers compared the data and found the PAR detected severe weather hazards several minutes in advance of the other radars. In one case the PAR captured storm evolution features that were not sampled by the WSR-88D. This was the first investigation of the meteorological advantages of the PAR.

In one case, researchers found over an eight-minute period the PAR captured the continuing evolution of storms in great detail including the development of a new cell that formed before the end of the first KTLX volume scan, a cell merger, and signs of dissipation. Another case observed by the PAR was a rapidly evolving severe storm with reflectivities exceeding 70dBZ and a TBSS (Three-body Scatter Spike - an indicator of hail) that would have been visible in only a few WSR-88D volumes, and its descent through the storm's life cycle would not have been as evident. Damage-producing severe microburst events were also sampled by the PAR a total of 23 times from the first detection of the core aloft to the outflow time. In comparison, the KTLX completed only three volume scans in the same period of time and did not sample the peak outflow.

PAR's rapid volume scan update time identified the evolution of hazardous severe weather features well ahead of the current capabilities of the WSR-88D radar. This timing provides a critical advantage for future forecasters and aviation users.