AMS Radar Conference 2015

amsNSSL scientists won’t have to travel far this year for the AMS Radar Conference! The 37th Conference on Radar Meteorology will be held right here in Norman, Oklahoma, at the Embassy Suites Hotel and Conference Center. The event, which takes place September 14-18,  will kick off with an icebreaker reception at the National Weather Center on the University of Oklahoma campus.

Participants are encouraged to sign up for tours of well-known Norman attractions, which will be offered on Wednesday, September 16. Locations open for tours will include the National Weather Center, NOAA’s National Weather Radar Testbed, OU’s Radar Innovations Laboratory, and OU’s Bizzell Library. On the tour of the National Weather Center, participants will see several NOAA facilities, including the Hazardous Weather Testbed, National Weather Service Norman forecast office, and the Storm Prediction Center. The tour of NOAA’s NWRT will offer the chance to learn firsthand how NSSL researchers test nd evaluate phased array radar.

This event is sponsored by the American Meteorological Society. Additional details can be found on their website:

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May 2013 Oklahoma tornado experimental warning products

The Hazardous Weather Testbed Spring Warning Experiment was operating May 20, 2013. Participants used the NSSL On Demand rotation tracks, the experimental Tornado Debris Signature algorithm, and GOES-R Proving Ground products during experimental warning operations.

The experimental Tornado Debris Signature algorithm output.
The experimental Tornado Debris Signature algorithm output that uses dual-pol radar data.
Rotation tracks product with EF-0 damage outline overlayed.
Rotation tracks product with EF-0 damage outline overlayed.
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NSSL scientists study tornadoes in their own backyard

May 24, 2011 Oklahoma tornadoes

Seven destructive tornadoes struck Oklahoma on May 24, 2011.  The tornadoes were well forecast by the National Weather Service (NWS), and NSSL was in position to capture the storms in several ways.

NSSL’s dual-polarized X-band mobile radar captured the early and mature stages of the first tornado reported near Canton Lake, Okla.  The data will be compared with another X-band dual-polarized radar for accuracy.  This storm produced an EF-3 tornado.

The phased array radar successfully sampled a tornadic supercell every one minute as it evolved and went on to produce devastating EF-4 damage in towns west of Oklahoma City, Okla.  A comparison of PAR data with the damage path shows that the radar captured rotation in the storm 12 minutes before it touched down. This tornado was on the ground for two hours with a 75-mile long track.

Visiting forecasters in the NOAA Hazardous Weather Testbed 2011 Spring Experiment found it interesting to be under the threat of tornadoes and then to be in the forecast path of them.  They watched the storms out the window and on the National Weather Radar Testbed Phased Array Radar along with the area Terminal Doppler Weather Radar and the NWS NEXRAD.  These radars showed the evolution of two confirmed tornadic debris balls as both storms moved towards Norman, Okla.  Participants also reported the NSSL/CIMMS weather-adaptive 3D variational data assimilation system (3DVAR) products all handled the track and evolution of the storms and tornadoes very well.

The American Red Cross of Central Oklahoma began using NSSL’s Warning Decision Support System – Integrated Information (WDSS-II) to map rotation tracks of the storm and deploy their teams by 8 a.m. the next day.

And, several NSSL scientists have been in the field as part of NWS teams to survey the tornado tracks and assign EF-Scale ratings based on the damage they find.  The EF-Scale is an estimate of the strength of the tornado based on damage to structures and vegetation.  Preliminary results show three tornadoes out of the seven in central Oklahoma were ranked a violent EF-4.

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Phased array radar captures evolution of a tornado at close range

Phased array radar scan verses WSR-88D scan of rotation in a storm

Subtle features in thunderstorms captured by rapid scanning phased array radar could alert forecasters to the potential of severe weather.

NSSL researchers used the National Weather Radar Testbed (NWRT) Phased Array Radar(PAR) to sample a tornadic supercell at a close 20km range for the first time.

The storm occurred on May 13, 2009 in central Oklahoma and produced an EF-0 tornado, heavy rain, and hailstones up to 2.5cm in diameter.

The storm also provided a unique research opportunity as it moved in-between the research radar and the National Weather Service WSR-88D operational radar. Because data were collected from two radars on the same storm, special analysis techniques were applied to estimate wind fields not usually obtainable by a single radar. This “dual-Doppler” analysis technique revealed subtle interactions inside the storm before the tornado formed.

Recent analysis of this storm revealed the 43 second update time of the PAR provided a much better depiction of the evolution of the tornado’s parent circulation than the 4.2 minute update time of the WSR-88D. The study also suggests that the tornado’s parent circulation resulted from the merging of two circulations, observed by several scans of PAR and the one scan of the WSR-88D.

Phased array radar technology uses an array of transmit and receive elements on a flat panel, and can collect the same weather information as a WSR-88D radar but in about one-sixth the time.  NSSL researchers continue to demonstrate PAR technology provides improved detection of severe weather hazards.

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