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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.

PAR identified the rapid evolution of low-level convergence and rotation, rapid intensification of a maturing storm cell, a merging process in three evolving cells, rapid development and descent of a hail core, and a microburst.  These are all critical pieces of information for forecasters and aviation users.

NSSL researchers anticipate continued data collection and comparison during the spring of 2007 and are looking forward to their first tornado observation.

Background:
The National Weather Radar Testbed was established at NSSL to provide the meteorological research community with the first surveillance phased array radar facility available on a full-time basis.  Phased-array radars that are electronically steered send out multiple beams from a stationary antenna – a volume scan can take less than 30 seconds.  These data collection capabilities improve resolution, accuracy and content of radar returns and, therefore, weather phenomena.  The surveillance capabilities of the WSR-88D are limited by the maximum mechanical rotation speed of the pedestal and the inclination of the antenna.  Rapid and significant storm development can occur while the WSR-88D radar is completing its volume scan, about 4.1 minutes even in rapid scan mode. 

Significance:
Earlier detection of hazardous severe weather using PAR has strong potential to aid forecasters in the forecast and warning decision process, helping to protect the aviation community and the public.

Outcome:
Supports overall goal to provide more accurate and timely warnings of high-impact weather events that disrupt economic productivity and cause loss of life and property.

2/21/07