NOAA Aviation Weather Center

The NOAA Hazardous Weather Testbed (HWT) conducts annual spring forecasting experiments organized by the Storm Prediction Center and National Severe Storms Laboratory to test and evaluate emerging scientific concepts and technologies for improved analysis and prediction of hazardous mesoscale weather. A primary goal is to accelerate the transfer of promising new scientific concepts and tools from research to operations through the use of intensive real-time experimental forecasting and evaluation activities conducted during the spring and early summer convective storm period. The 2010 NOAA/HWT Spring Forecasting Experiment (SE2010), conducted 17 May through 18 June, had a broad focus, with emphases on heavy rainfall and aviation weather, through collaboration with the Hydrometeorological Prediction Center (HPC) and the Aviation Weather Center (AWC), respectively. In addition, using the computing resources of the National Institute for Computational Sciences at the University of Tennessee, the Center for Analysis and Prediction of Storms at the University of Oklahoma provided unprecedented real-time conterminous United States (CONUS) forecasts from a multimodel Storm-Scale Ensemble Forecast (SSEF) system with 4-km grid spacing and 26 members and from a 1-km grid spacing configuration of the Weather Research and Forecasting model. Several other organizations provided additional experimental high-resolution model output. This article summarizes the activities, insights, and preliminary findings from SE2010, emphasizing the use of the SSEF system and the successful collaboration with the HPC and AWC. A supplement to this article is available online (DOI:10.1175/BAMS-D-11-00040.2)

Abstract A new strategy for generating and presenting model diagnostic fields from convection-allowing forecast models is introduced. The fields are produced by computing temporal-maximum values for selected diagnostics at each horizontal grid point between scheduled output times. The two-dimensional arrays containing these maximum values are saved at the scheduled output times. The additional fields have minimal impacts on the size of the output files and the computation of most diagnostic quantities can be done very efficiently during integration of the Weather Research and Forecasting Model. Results show that these unique output fields facilitate the examination of features associated with convective storms, which can change dramatically within typical output intervals of 1–3 h.

Abstract For the next generation of the World Area Forecast System (WAFS), the global Graphical Turbulence Guidance (G-GTG) has been developed using global numerical weather prediction (NWP) model outputs as an input to compute a set of turbulence diagnostics, identifying strong spatial gradients of meteorological variables associated with clear-air turbulence (CAT) and mountain-wave turbulence (MWT). The G-GTG provides an atmospheric turbulence intensity metric of energy dissipation rate (EDR) to the 1/3 power (m 2/3 s –1 ), which is the International Civil Aviation Organization (ICAO) standard for aircraft reporting. Deterministic CAT and MWT EDR forecasts are derived from ensembles of calibrated multiple CAT and MWT diagnostics, respectively, with the final forecast provided by the gridpoint-by-gridpoint maximum of the CAT and MWT ensemble means. In addition, a probabilistic EDR forecast is produced by the percentage agreement of the individual CAT and MWT diagnostics that exceed a certain EDR threshold for turbulence (i.e., multidiagnostic ensemble). Objective evaluations of the G-GTG against global in situ EDR measurement data show that both deterministic and probabilistic G-GTG significantly improve the current WAFS CAT product, mainly because the G-GTG takes into account turbulence from various sources related to CAT and MWT. The probabilistic G-GTG forecast is more reliable at predicting light-or-greater (EDR > 0.15)- than moderate-or-greater (EDR > 0.22)-level turbulence, although it suffers from overforecasting. This will be improved in the future when we use this methodology with NWP ensembles and more observation data will be available for calibration. We expect that the new G-GTG forecasts will be beneficial to aviation users globally.

Abstract The variation of wind-optimal transatlantic flight routes and their turbulence potential is investigated to understand how upper-level winds and large-scale flow patterns can affect the efficiency and safety of long-haul flights. In this study, the wind-optimal routes (WORs) that minimize the total flight time by considering wind variations are modeled for flights between John F. Kennedy International Airport (JFK) in New York, New York, and Heathrow Airport (LHR) in London, United Kingdom, during two distinct winter periods of abnormally high and low phases of North Atlantic Oscillation (NAO) teleconnection patterns. Eastbound WORs approximate the JFK–LHR great circle (GC) route following northerly shifted jets in the +NAO period. Those WORs deviate southward following southerly shifted jets during the −NAO period, because eastbound WORs fly closely to the prevailing westerly jets to maximize tailwinds. Westbound WORs, however, spread meridionally to avoid the jets near the GC in the +NAO period to minimize headwinds. In the −NAO period, westbound WORs are north of the GC because of the southerly shifted jets. Consequently, eastbound WORs are faster but have higher probabilities of encountering clear-air turbulence than westbound ones, because eastbound WORs are close to the jet streams, especially near the cyclonic shear side of the jets in the northern (southern) part of the GC in the +NAO (−NAO) period. This study suggests how predicted teleconnection weather patterns can be used for long-haul strategic flight planning, ultimately contributing to minimizing aviation’s impact on the environment.

Abstract. Some of the Aircraft Meteorological Data Relay (AMDAR) data include a turbulence metric of the derived equivalent vertical gust (DEVG), in addition to wind and temperature. As the cube root of the eddy dissipation rate (EDR) is the International Civil Aviation Organization standard turbulence reporting metric, we attempt to retrieve the EDR from the DEVG for more reliable and consistent observations of aviation turbulence globally. Using the DEVG in the AMDAR data archived from October 2015 to September 2018 covering a large portion of the Southern Hemisphere and North Pacific and North Atlantic oceans, we convert the DEVG to the EDR using two methods, after conducting quality control procedures to remove suspicious turbulence reports in the DEVG. The first method remaps the DEVG to the EDR using a lognormal mapping scheme, while the second one uses the best-fit curve between the EDR and DEVG developed in a previous study. The DEVG-derived EDRs obtained from the two methods are evaluated against in situ EDR data reported by US-operated carriers. For two specified regions of the Pacific Ocean and Europe, where both the DEVG-derived EDRs and in situ EDRs were available, the DEVG-derived EDRs obtained by the two methods were generally consistent with in situ EDRs, with slightly better statistics obtained by the first method than the second one. This result is encouraging for extending the aviation turbulence data globally with the single preferred EDR metric, which will contribute to the improvement of global aviation turbulence forecasting as well as to the construction of the climatology of upper-level turbulence.

Abstract The relationship between 700-mb temperatures and convective severe storm reports is examined using data from 1993 to 2006 for the contiguous United States. Severe storm reports are used as a rough “proxy” for the occurrence of deep moist convection, and spatial and temporal distributions of 700-mb temperatures associated with these reports are analyzed. Secondarily, the distributions are assessed by individual severe storm report type, and convective inhibition also is evaluated. The motivation for this study is derived from the occasionally used 10°–12°C at 700 mb rule of thumb for estimating the extent and strength of the capping inversion. Whereas there is a semblance of merit for using this rule at times, its utility is shown to be strongly dependent on 1) geographic location, particularly with respect to surface elevation and the frequency of elevated mixed layers, and 2) the time of year. Calculation of convective inhibition, careful examination of the sounding, and assessment of lifting mechanisms likely are more valuable than 700-mb temperatures when forecasting the potential for deep moist convection and severe storms.

Report on the Fifth Workshop on Aviation Meteorology, Jeju Island, Korea, 2–4 November 2016. Topics: DEVELOPMENT OF GLOBAL AVIATION TURBULENCE FORECASTING SYSTEMS; IMPROVEMENTS IN MODELING AND OBSERVING SYSTEMS OF AVIATION METEOROLOGY; LOCAL WEATHER FORECASTS AND LOW-LEVEL WIND SHEAR; INTERACTION BETWEEN AVIATION AND CLIMATE CHANGE.

When planning a flight, pilots have traditionally consulted with trained weather briefers who gather, select, review, and to some extent interpret aviation weather products for them. Today, pilots can directly access these same weather products from their own computers, aircraft cockpits, and mobile devices, and choose to skip the services offered by weather briefers. A sample of 191 general aviation pilots completed a survey designed to determine how frequently they directly access weather products, how frequently they still consult with weather briefers, and which weather products pilots use and why. We identified a subset of surveyed pilots who usually or always rely solely on directly accessed weather products (approximately 25%). Although these self-briefing pilots trend toward holding higher grades of pilot certificates and make greater use of cockpit weather systems, they do not differ from other pilots in the weather products they review, and they prefer simple weather observations to more complex forecasts and descriptions of larger weather systems such as fronts and pressure regions. We explore the reasons why self-briefing pilots choose to review the products they do, and how the next generation of pilots might best be trained and supported.

© 2023 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). Corresponding author: Stephanie Avey, stephanie.avey@noaa.gov Publisher's Note: This article was modified on 11 July 2023 to correct the affiliation for authors Heather Reeves and Patrick Skinner.

Weather is responsible for approximately 70% of air transportation delays in the National Airspace System, and delays resulting from convective weather alone cost airlines and passengers millions of dollars each year due to delays that could be avoided. This research sought to establish relationships between environmental variables and airport efficiency estimates by data mining archived weather and airport performance data at ten geographically and climatologically different airports. Several meaningful relationships were discovered from six out of ten airports using various machine learning methods within an overarching data mining protocol, and the developed models were tested using historical data.

Abstract. Some of the Aircraft Meteorological Data Relay (AMDAR) data include a turbulence metric of the derived equivalent vertical gust (DEVG), in addition to wind and temperature. As the cube root of the eddy dissipation rate (EDR) is the International Civil Aviation Organization standard turbulence reporting metric, we attempt to retrieve the EDR from the DEVG for more reliable and consistent observations of aviation turbulence globally. Using the DEVG in the AMDAR archived from October 2015 to September 2018 covering a large portion of the Southern Hemisphere and North Pacific and North Atlantic Oceans, we convert the DEVG to the EDR using two methods, after conducting quality control procedures to remove suspicious turbulence reports in the DEVG. The first method is to remap the DEVG to the EDR using a lognormal mapping scheme, while the second one is using the best-fit curve between the EDR and DEVG developed in the previous study. The DEVG-derived EDRs obtained from the two methods are evaluated against in situ EDR data reported by United States-operated carriers. For two specified regions of the trans-Pacific Ocean and Europe, where both the DEVG-derived EDRs and in situ EDRs were available, the DEVG-derived EDRs obtained by the two methods are generally consistent with in situ EDRs, with slightly better statistics by the first method than the second one. This result is encouraging for extending the aviation turbulence data globally with the single preferred EDR metric, which will contribute to the improvement of global aviation turbulence forecasting as well as to the construction of the climatology of upper-level turbulence.

Two cases of tornadoes associated with cold-core 500-mb lows are presented in order to continue building a formal documented catalog of these events. Although environments associated with these tornadoes are considered atypical for strong tornadoes with supercells, one of these cases produced a tornado that resulted in F2 damage while the other case missed useful damage indicators. These events do not follow the classical conceptual model of environments capable of producing strong tornadoes because there is less surface moisture and deep-layer buoyancy. As such, these events are often poorly anticipated or missed completely by forecasters. It is important to build a catalog and continue to adapt the conceptual model of these events in order to prepare and warn for them better and more efficiently in the future. Recommendations are provided on how to handle these events in both the outlook period (>1 h) and for warnings in an effort to improve both situational awareness and statistics.

Effectively communicating hazardous weather conditions to the general aviation (GA) community is acontinuously evolving effort of US National Weather Service (NWS) Aviation Weather Center (AWC)operations. AWC has started to transition text heavy products in favor of easily interpreted dynamicgraphics that provide additional information that was never fully realized through text alone.AWC provides domestic and international aviation weather forecasts and warnings, disseminatedthrough traditional product dissemination as well as directly to end users through AviationWeather.gov.The web site is currently undergoing a complete rewrite, in order to both modernize and improveconsistency. Customer feedback has been gathered over multiple years and the rewrite is intended toaddress a number of issues in a comprehensive manner.Many products that were previously available in multiple formats are now presented through a moreintegrated framework, allowing for the user to combine different datasets as desired. The GraphicalForecasts for Aviation (GFA), first developed as a replacement for the traditional text Area Forecast,now spans a wide variety of weather information in a one stop Geographic Information Systems (GIS)interactive web framework. The site is designed to adjust to available screen real estate, making thesame data and interface available on a variety of platforms from desktop computers to tablets andphones.The new site has been in an experimental status since spring of 2022, while AWC collects feedback onthe new design and performed a social science user assessment in partnership with the US FederalAviation Administration’s (FAA) Aviation Weather Demonstration and Evaluation service group. Thispresentation will discuss the design and features of the new site, as well as lessons learned from theaviation weather user community during the development and evaluation.