Comparisons of Mid-Altitude Radial Convergence Signatures in Severe Storms from KDGX and KULM

Comparisons of Mid-Altitude Radial Convergence Signatures in Severe Storms from KDGX and KULM

Janae Elkins, Jackson State University

Eric Carpenter, NWS Jackson, MS

Dr. Duanjun Lu, Jackson State University

Dr. Todd A. Murphy, University of Louisiana at Monroe

Dr. Anne Case Hanks, University of Louisiana at Monroe

The National Weather Service (NWS) has a duty to provide real-time information, including warnings, emergencies, and other service products that are dependent on a network of radars (NEXRAD). Although this network is impressive, coverage and sampling can be deficient in some areas. This can be due to the long range of the radar from the storms, or unfavorable orientation of the radar with the storm-scale flow. It is an advantage for forecasters to have and use multiple radars to sample storms and send warnings. This tactic is very important, especially during a severe weather event when just split seconds in decision-making can save lives.

The primary radar used for warning services in the NWS Jackson, MS county warning area is KDGX, located in Brandon, MS. Up until recently, KDGX provided the best data coverage in much of the Delta region, including extreme southeast Arkansas and northeast Louisiana, and northwest Mississippi. But as of 2017, a new S-band polarimetric radar, KULM, is being operated by the University of Louisiana at Monroe in northeast Louisiana, and this radar has already brought operational benefits, especially in terms of tornado detection and improved tornado warnings. While the focus has been on documenting improvements as they relate to tornado warning issuances, the hope here is to document additional improvements related to severe weather, including radar signatures associated with straight-line winds in severe thunderstorms.

The purpose of this presentation was finding and comparing MARC (Mid Altitude Radial Convergence) signatures between KULM and KDGX, and to emphasize cases when better sampling at KULM helped to improve warning services for NWS Jackson, MS. This was done by searching numerous severe weather events from the first half of 2017 for severe storms and damaging straight-line wind reports occurring in the Delta region, and then comparing velocity and reflectivity data from the two radars. Data from the following events was used in this presentation: 25 March, 29 March, 2 April, 30 April, 28 May, and 1 July.