Assessing Real-Time Tornado Information Disseminated through NWS Products

Abstract

Real-time confirmation of a tornado specified in National Weather Service (NWS) warnings and statements is believed to increase the credibility and urgency of these critical warning messages for the end user, because it represents the greatest degree of certainty that the hazard exists. This timely tornado information disseminated in official NWS products and relayed through multiple sources by private and public partners may help the public believe, personalize, confirm, and respond to the warning message. This is the first study to explicitly assess the frequency of real-time confirmation of ongoing tornadoes within NWS products and explore what unique conditions may facilitate or hinder this process. Tornado reports and their respective NWS warnings and statements during a 5-yr period from 2007 to 2011 across the central contiguous United States were compiled and examined. Overall, 40% of tornadoes were confirmed in NWS products in real time. Increasing tornado pathlength, duration, and intensity subsequently resulted in an increasing likelihood of real-time confirmation prior to the tornado dissipating. The time of day was a factor; nighttime tornadoes were 20% less likely to receive real-time confirmation than daytime events. Additionally, increasing tornado forecast risk in products issued by the Storm Prediction Center corresponded to an increasing likelihood of real-time confirmation. Analysis of these data reveals specific scenarios when tornadoes are more or less likely to be reported in real time, providing some guidance for when timely ground-truth information may or may not be available.

Diagnosing the Conditional Probability of Tornado Damage Rating Using Environmental and Radar Attributes

“…15). 1) real-time comparison of available observations with the model-based estimates of the storm environment, 2) real-time monitoring of storm structure and rotational characteristics via WSR-88D sampling, and 3) supporting evidence of a tornado via the development of a dual-polarization tornadic debris signature (DPTDS; e.g., Bodine et al 2013;Schultz et al 2012a,b; Bunkers and Baxter 2011) with vertical and temporal continuity, since a majority of tornadoes are not reported to local National Weather Service offices in real time (Blair and Leighton 2014). 13.…”

“…Newman et al (2013) found utility in applying range correction to the local, linear least squares derivatives (LLSDs; Smith and Elmore 2004) azimuthal shear algorithm, and this procedure aided in differentiating between nontornadic and tornadic radar scans for a small number of events. Blair and Leighton (2014) noted the need for robust, scientific guidance for real-time tornado intensity estimates in their assessment of event confirmation in NWS warnings and statements across the central continental United States (CONUS) from 2007 to 2011. The early studies investigating the relationship between tornado intensity and radar (e.g., Kingfield et al 2012;LaDue et al 2012;Toth et al 2013) have shown some ability to identify different levels of tornado intensity in a diagnostic manner, thereby lending credence to the underlying idea of tornado intensity identification, from which IBW is based.…”

Dissipation Characteristics of Tornadic Vortex Signatures Associated with Long-Duration Tornadoes

“…Therefore, given a sufficiently short distance and clear line of sight between the radar and the tornado, identification of existing tornadoes in Doppler weather radar data is nearly ubiquitous. The TVS and TDS serve as useful tornado proxies both for forecasters issuing warnings (e.g., Blair and Leighton 2014) and for researchers conducting observational studies (e.g., Trapp et al 1999).…”

Spatial and Temporal Characteristics of Polarimetric Tornadic Debris Signatures

“…Last, a TDS often persists for a significant time after tornado demise, which makes sense given observations of long-range debris transport (e.g., Magsig and Snow 1998). Even with these limitations, the TDS remains a good indicator of lofted debris and is especially useful in the absence of a spotter network (e.g., Blair and Leighton 2014).…”