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1. Optimizing radar scan strategies for tracking isolated deep convection using observing system simulation experiments

   https://doi.org/10.5194/amt-15-4931-2022  

   Oue, Mariko; Saleeby, Stephen M.; Marinescu, Peter J.; Kollias, Pavlos; van den Heever, Susan C. (January 2022, Atmospheric Measurement Techniques)

   Abstract. Optimizing radar observation strategies is one of the mostimportant considerations in pre-field campaign periods. This is especiallytrue for isolated convective clouds that typically evolve faster than theobservations captured by operational radar networks. This study investigatesuncertainties in radar observations of the evolution of the microphysicaland dynamical properties of isolated deep convective clouds developing inclean and polluted environments. It aims to optimize the radar observationstrategy for deep convection through the use of high-spatiotemporalcloud-resolving model simulations, which resolve the evolution of individualconvective cells every 1 min, coupled with a radar simulator and a celltracking algorithm. The radar simulation settings are based on the TrackingAerosol Convection Interactions ExpeRiment (TRACER) and Experiment of SeaBreeze Convection, Aerosols, Precipitation and Environment (ESCAPE) fieldcampaigns held in the Houston, TX, area but are generalizable to other fieldcampaigns focusing on isolated deep convection. Our analysis produces thefollowing four outcomes. First, a 5–7 m s−1 median difference inmaximum updrafts of tracked cells is shown between the clean and pollutedsimulations in the early stages of the cloud lifetimes. This demonstratesthe importance of obtaining accurate estimates of vertical velocity fromobservations if aerosol impacts are to be properly resolved. Second,tracking of individual cells and using vertical cross section scanning every minute capture the evolution of precipitation particle number concentration and size represented by polarimetric observables better than the operational radar observations that update the volume scan every 5 min. This approach also improves multi-Doppler radar updraft retrievals above 5 km above ground level for regions with updraft velocities greater than 10 m s−1. Third, we propose an optimized strategy composed of cell tracking by quick (1–2 min) vertical cross section scans from more than oneradar in addition to the operational volume scans. We also propose the useof a single-RHI (range height indicator) updraft retrieval technique for cellsclose to the radars, for which multi-Doppler radar retrievals are stillchallenging. Finally, increasing the number of deep convective cells sampledby such observations better represents the median maximum updraft evolutionwith sample sizes of more than 10 deep cells, which decreases the errorassociated with sampling the true population to less than 3 m s−1. 

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2. An Analysis of an Ostensible Anticyclonic Tornado from 9 May 2016 Using High-Resolution, Rapid-Scan Radar Data

   https://doi.org/10.1175/WAF-D-20-0055.1  

   Snyder, Jeffrey C.; Bluestein, Howard B.; Wienhoff, Zachary B.; Kuster, Charles M.; Reif, Dylan W. (October 2020, Weather and Forecasting)

   null (Ed.)

   Abstract Tornadic supercells moved across parts of Oklahoma on the afternoon and evening of 9 May 2016. One such supercell, while producing a long-lived tornado, was observed by nearby WSR-88D radars to contain a strong anticyclonic velocity couplet on the lowest elevation angle. This couplet was located in a very atypical position relative to the ongoing cyclonic tornado and to the supercell’s updraft. A storm survey team identified damage near where this couplet occurred, and, in the absence of evidence refuting otherwise, the damage was thought to have been produced by an anticyclonic tornado. However, such a tornado was not seen in near-ground, high-resolution radar data from a much closer, rapid-scan, mobile radar. Rather, an elongated velocity couplet was observed only at higher elevation angles at altitudes similar to those at which the WSR-88D radars observed the strong couplet. This paper examines observations from two WSR-88D radars and a mobile radar from which it is argued that the anticyclonic couplet (and a similar one ~10 min later) were actually quasi-horizontal vortices centered ~1–1.5 km AGL. The benefits of having data from a radar much closer to the convective storm being sampled (e.g., better spatial resolution and near-ground data coverage) and providing more rapid volume updates are readily apparent. An analysis of these additional radar data provides strong, but not irrefutable, evidence that the anticyclonic tornado that may be inferred from WSR-88D data did not exist; consequently, upon discussions with the National Weather Service, it was not included in Storm Data. 

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3. Examining Meteorological Benefits of Rapid-Scan, Fully Digital Phased Array Radar Observations for Detecting Tornado Formation and Intensification

   https://doi.org/10.1175/JTECH-D-24-0104.1  

   Cohen, Brandon K; Bodine, David J; Yeary, Mark B; Snyder, Jeffrey C; Bluestein, Howard B (June 2025, Journal of Atmospheric and Oceanic Technology)

   Abstract This study focuses on the application of phased array radars (PARs) to observe tornadoes and their formation. PAR technology for meteorological applications is maturing and may become a valuable tool for the meteorological community. A fully digital PAR offers a range of benefits including adaptive scanning techniques, higher temporal resolution especially via radar imaging modes, and denser vertical sampling to allow for more complete observations of severe hazard structure and evolution. To best understand the benefits of such a system, synthetic PAR observations are generated from archived mobile rapid-scan observations collected by the Rapid X-band Polarimetric radar (RaXPol) to emulate typical operational radar ranges and PAR-enabled scanning strategy effects. In this study, a synthetic PAR data tool is applied to two tornadic cases (24 May 2011 El Reno, Oklahoma, tornado and the 24 May 2016 Dodge City, Kansas, tornadoes) and one non-tornadic case (17 April 2013). Results indicate that, despite increasing standoff ranges and using vertical imaging, a PAR can still observe a similar mode of tornadogenesis (i.e., non-descending TVS) as traditional mobile systems but with a slight delay in observing intensification at increasing standoff ranges and reduced change in measured intensity. The PAR-enabled vertical imaging mode does not eliminate our ability to identify the TVS at different spoiling factors, but changes to the structure of the TVS may have operational implications. We hope that the improved understanding of meteorological benefits from these synthetic PAR data can provide useful insight for fully digital PAR radar placement and warning operations. 

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4. Evaluating Planetary Boundary Layer and Land Surface Models via Dual-Polarization WSR-88D and Flux Tower Observations

   https://doi.org/10.1175/MWR-D-25-0032.1  

   Stouffer, Braedon C; Stensrud, David J; Zhang, Yunji (September 2025, Monthly Weather Review)

   Recent work has taken advantage of the existing national network of dual-polarization WSR-88D radars to produce accurate daytime planetary boundary layer (PBL) depth estimates for every radar volume scan (roughly every 10 min or less) at WSR-88D sites across the United States. We expand on this work by comparing hourly forecasts of daytime PBL depth from the Mellor–Yamada–Nakanishi–Niino eddy diffusivity–mass flux (MYNN-EDMF) PBL scheme to estimates obtained from WSR-88D observations for calendar year 2022. Forecasts from the operational Rapid Refresh (RAP) model that uses the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) Model are used to generate this large dataset for analysis. We find that MYNN-EDMF forecasts of PBL depth can differ significantly from WSR-88D observations in both timing of growth and maximum depth of the PBL with consistent biases in PBL depth across regions and seasons. These biases are then evaluated through the comparison of parameterized surface sensible and latent heat fluxes to those observed by flux towers located near selected radar sites. We find that errors in predicted PBL depths are strongly correlated with the over-/underestimation of surface sensible heat flux. Further assessment of modeled soil moisture reveals that the land surface model utilized by RAP is likely contributing to PBL depth biases in summer months through erroneous drying of soil, which increases surface sensible heat flux and therefore PBL depth. 

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5. On Discrete Convective Updrafts and Tornadoes in Quasi-Linear Convective Systems

   https://doi.org/10.1175/WAF-D-24-0080.1  

   Wolff, Edward C; Trapp, Robert J; Nesbitt, Stephen W; Parker, Matthew D; Kosiba, Karen A; Wurman, Joshua (July 2025, Weather and Forecasting)

   Abstract This research attempts to use operational radar and satellite products to identify potential locations of quasi-linear convective system (QLCS) tornadogenesis, which can be difficult to predict. It is hypothesized that deep, discrete updrafts indicate portions of the QLCS capable of producing tornadoes, whereas shallower convection indicates more benign portions of the QLCS. To address this hypothesis, storm reports and storm surveys on 30–31 March 2022, during the second intensive observing period of the 2022 Propagation, Evolution, and Rotation in Linear Storms (PERiLS) field campaign, are used to identify locations of tornadoes within the QLCS. These tornado locations are then compared to representations of upper-tropospheric updrafts, namely, overshooting tops (OTs), which are identified with an algorithm using 1-min-resolution mesoscale sector data fromGOES-16Advanced Baseline Imager infrared brightness temperatures, and radar reflectivity cores aloft, identified with Multi-Radar Multi-Sensor (MRMS) 3D mosaic reflectivity products. Only a fraction (less than 30%) of tornadoes within the QLCS are associated with OTs, though over 85% of tornadoes are located near convective cores as indicated by cores of enhanced reflectivity at 9 km MSL. A numerical simulation of the event is also conducted using the Weather Research and Forecasting (WRF) Model which shows a strong relationship between simulated updraft intensity and reflectivity aloft. Given this apparent support of the hypothesis, the identification of updraft signatures within MRMS and high-resolution geostationary satellite data may ultimately help improve the identification of regions within QLCSs most likely to result in tornadoes. 

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