Special Issue "Advancements in Mesoscale Weather Analysis and Prediction"

A special issue of Atmosphere (ISSN 2073-4433). This special issue belongs to the section "Meteorology".

Deadline for manuscript submissions: closed (29 February 2020).

Special Issue Editors

Dr. Jason C. Knievel
E-Mail Website
Guest Editor
National Center for Atmospheric Research, Boulder, CO 80305, USA
Interests: mesoscale meteorology, microscale meteorology; weather analysis and forecasting; numerical weather prediction (NWP); urban meteorology; land–atmosphere interactions; atmospheric boundary layer; moist convection; mesoscale convective vortices; density currents; gravity waves; mountain waves; tropical cyclones; wildfires; flash floods; ensemble prediction systems (EPS); model verification; Weather Research and Forecasting (WRF) Model; Cloud Model 1 (CM1); field projects; technology transfer; research-to-operations (R2O) transition; scientific communication
Dr. Ligia R. Bernardet
E-Mail Website
Guest Editor
Cooperative Institute for Research in Environmental Sciences at the National Oceanic and Atmospheric Administration Global Systems Division, Boulder, CO, USA
Interests: mesoscale meteorology; weather analysis and forecasting; tropical meteorology; tropical cyclones; microphysics; radiative transfer; moist convection; physical parameterizations; numerical weather prediction (NWP); model testing; model verification; research-to-operations (R2O) transition; community model development best practices; training and education
Dr. Thomas J. Galarneau Jr.
E-Mail Website
Guest Editor
Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
Interests: synoptic meteorology; mesoscale meteorology; weather analysis and forecasting; numerical weather prediction (NWP); severe local storms; tropical meteorology; tropical cyclones; cyclogenesis; storm surge; monsoons; atmospheric boundary layer; land–atmosphere interactions; moist convection; mesoscale convective vortices; atmospheric rivers; moisture transport; ensemble prediction systems (EPS); model verification; atmospheric predictability; Weather Research and Forecasting (WRF) Model; field projects

Special Issue Information

Dear Colleagues,

Weather analysis and prediction at the fine mesoscale have been standard in operations and research for decades, thanks to myriad advancements in numerical modeling, data assimilation, atmospheric sensing, computing, communications, and related technologies. Even while faster computers and other innovations make the microscale an increasingly practical goal, the mesoscale remains fundamental in weather analysis and prediction.

This Special Issue showcases advancements across a range of topics on which skillful, useful mesoscale weather analysis and prediction depend. Leading the list of dependencies is the understanding of dynamical and physical mesoscale processes, along with the ability to use this knowledge to advance analyses and predictions. Cornerstones of this effort are observations for characterizing the atmosphere’s state and various methods of assimilating those observations. Improvements to dynamical and statistical models mean that the atmosphere can be represented ever more faithfully and in more detail. With probabilistic approaches, including ensembles, it is possible to address uncertainty in models and in the state of the atmosphere. As models and their use become more sophisticated, so do approaches to evaluating models’ skill and utility. Innovations in computation and data management enable progress in research and operations. Finally, a comprehensive treatment of the subject must consider stakeholders and their applications (coupled models, decision support systems, etc.).

We invite submissions on any of the topics listed above. Manuscripts may present original research or review previous work and summarize the current state of the science, thereby providing context to the current research and the direction in which the field is moving.

Dr. Jason C. Knievel
Dr. Ligia R. Bernardet
Dr. Thomas J. Galarneau Jr.
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Atmosphere is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • mesoscale
  • weather analysis and forecasting
  • numerical weather prediction (NWP)
  • ensemble prediction systems (EPS)
  • predictability
  • probabilistic prediction
  • bias correction
  • post-processing
  • data assimilation
  • numerical methods
  • physical parameterizations
  • machine learning
  • artificial intelligence
  • observing platforms
  • remote sensing
  • land–atmosphere interactions
  • atmospheric boundary layer
  • urban meteorology
  • severe local storms
  • coupled applications
  • coupled models
  • model verification
  • decision support systems
  • research-to-operations (R2O) transition

Published Papers (10 papers)

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Research

Article
A Numerical Study of Windstorms in the Lee of the Taebaek Mountains, South Korea: Characteristics and Generation Mechanisms
Atmosphere 2020, 11(4), 431; https://doi.org/10.3390/atmos11040431 - 24 Apr 2020
Viewed by 1094
Abstract
The Yeongdong region, located east of the Taebaek Mountains, South Korea, often experiences severe windstorms in spring, causing a lot of damages, especially when forest fires spread out rapidly by strong winds. Here, the characteristics and generation mechanisms of the windstorms in the [...] Read more.
The Yeongdong region, located east of the Taebaek Mountains, South Korea, often experiences severe windstorms in spring, causing a lot of damages, especially when forest fires spread out rapidly by strong winds. Here, the characteristics and generation mechanisms of the windstorms in the Yeongdong region on 8 April 2012 are examined through a high-resolution Weather Research and Forecasting (WRF) model simulation. In the Yangyang area, the steep descent of the isentropes on the lee slope of the mountain and their recovery farther leeward are seen. Inversion layers and incoming flow in hydraulic jump regime suggest that the hydraulic jump is responsible for the downslope windstorm. In the Jangjeon area, the plume-shaped wind pattern extending seaward from the gap exit is seen when the sea-level pressure difference between the gap inside and the gap exit, being responsible for the gap winds, is large. In the Uljin area, downslope windstorms pass over the region with weak wind, low Richardson number, and deep planetary boundary layer (PBL), making banded pattern in the wind and PBL height fields. This study demonstrates that the characteristics of the windstorms in the lee of the Taebaek Mountains and their generation mechanisms differ depending on local topographic features. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
The Role of Background Wind and Moisture in the Atmospheric Response to Oceanic Eddies During Winter in the Kuroshio Extension Region
Atmosphere 2019, 10(9), 527; https://doi.org/10.3390/atmos10090527 - 07 Sep 2019
Cited by 1 | Viewed by 1099
Abstract
The role of background wind and moisture in the atmospheric response to oceanic eddies during winter in the Kuroshio Extension (KE) region is examined by numerical experiments (EXPs) using the Weather Research and Forecasting (WRF) model. We designed two sets of parallel experiments [...] Read more.
The role of background wind and moisture in the atmospheric response to oceanic eddies during winter in the Kuroshio Extension (KE) region is examined by numerical experiments (EXPs) using the Weather Research and Forecasting (WRF) model. We designed two sets of parallel experiments (dry and wet EXPs). The dry EXPs exclude the moisture in the air and the evaporation process. Each experiment differs only in the background wind speed during the initial condition. The wet EXPs include humidity in the initial condition and evaporation during the integration; the other settings are the same as the dry EXPs. The atmosphere in the two sets of EXPs are forced by the same mesoscale sea surface temperature anomaly which resembles the oceanic warm eddy in KE region. The results of these EXPs confirm that under weak background wind conditions, the atmospheric secondary circulation over oceanic eddies is driven by the pressure adjustment process due to weak advection. In the case of the dry run, the increase in background wind enhances the sea surface wind (SSW) by increasing vertical mixing. The convergence of SSW induces vertical motion and heating in the boundary layer, which further decreases the instability. The atmospheric secondary circulation in the dry run remains within the boundary layer. In wet EXPs, the atmospheric response is similar to that in dry runs when the background wind is very weak. When the background wind speed is increased to the climatology value (in KE region) or higher, the vertical motion triggers the precipitation process and diabatic heating above the boundary layer, and the heating in turn reinforces the upward flow. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Spatial Predictability of Heavy Rainfall Events in East China and the Application of Spatial-Based Methods of Probabilistic Forecasting
Atmosphere 2019, 10(9), 490; https://doi.org/10.3390/atmos10090490 - 26 Aug 2019
Cited by 2 | Viewed by 1223
Abstract
One of the major issues in developing convective-scale ensemble forecasts is what is widely known as under-dispersion. This can be addressed through the consideration of spatial uncertainties via post-processing, motivating the development of various techniques to represent the spatial uncertainties of ensembles. In [...] Read more.
One of the major issues in developing convective-scale ensemble forecasts is what is widely known as under-dispersion. This can be addressed through the consideration of spatial uncertainties via post-processing, motivating the development of various techniques to represent the spatial uncertainties of ensembles. In this study, a recently developed fraction-based approach (the ensemble agreement scale, EAS) is applied to characterize the spatial predictability and spread–skill performances of precipitation forecasts using a WRF-EnKF convective-scale ensemble forecast system over the Yangtze and Huai river valleys, China. Fourteen heavy rainfall events during the Meiyu season of 2013 and 2014 were classified into two categories—strong forcing (SF) and weak forcing (WF)—using the convective adjustment timescale. The results show that the spatial predictability and spread–skill relationship are highly regime-dependent and that both exhibit lower values under WF. Furthermore, a new object-based probabilistic approach (OBJ_NEP) is proposed as a supplement to traditional neighborhood ensemble probability (NEP) and a recently proposed fraction-based approach (EAS_NEP). The results of the application of OBJ_NEP are evaluated, and a comparison is made between NEP and EAS_NEP for the analysis of experiments involving both idealized and ‘real’ events by using objective verification methods. The results imply that OBJ_NEP can be effectively employed under different large-scale forcings. Consequently, these results can aid the understanding of spatial-based approaches to probabilistic forecasting, which has been widely applied to post-processing processes of convective-scale ensemble forecast systems (CSEFs) in recent years. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Analysis of Possible Triggering Mechanisms of Severe Thunderstorms in the Tropical Central Andes of Peru, Mantaro Valley
Atmosphere 2019, 10(6), 301; https://doi.org/10.3390/atmos10060301 - 01 Jun 2019
Cited by 13 | Viewed by 1555
Abstract
The aim of the present study is to analyze the triggering mechanisms of three thunderstorms (TSs) associated with severe rainfall, hail and lightening in the tropical central Andes of Peru, specifically above the Huancayo observatory (12.04 S, 75.32 W, 3313 m [...] Read more.
The aim of the present study is to analyze the triggering mechanisms of three thunderstorms (TSs) associated with severe rainfall, hail and lightening in the tropical central Andes of Peru, specifically above the Huancayo observatory (12.04 S, 75.32 W, 3313 m a.s.l.) located in the Mantaro valley during the spring-summer season (2015–2016). For this purpose, we used a set of in-situ pluviometric observations, satellite remote sensing data, the Compact Meteorological Ka-Band Cloud Radar (MIRA-35C), the Boundary Layer Tropospheric Radar and downscaling model simulations with the Weather Research and Forecasting (WRF) Model (resolutions: 18 km, 6 km and 2 km), and the Advance Regional Prediction System (ARPS) (resolution: 0.5 km) models in order to analyze the dynamic of the atmosphere in the synoptic, meso and local scales processes that control the occurrence of the three TS events. The results show that at synoptic scale, the TSs are characterized by the southern displacement of the South-east Pacific Subtropical Anticyclone up to latitudes higher than 35 S, by the weakening and south-eastern displacement of the Bolivian high–North east low system and by the intrusion of westerly winds along the west side of the central Andes at upper and medium levels of the atmosphere. At meso-scale, apparently, two important moisture fluxes from opposite directions are filtered through the passes along the Andes: one from the north-west and the other from the south-east directions converge and trigger the deep convection into the Mantaro valley. These moisture fluxes are generated by the intrusion of the sea-breeze from the Pacific ocean along the west of the Andes coupling with upper and middle westerly winds and by the thermally induced moisture fluxes coming from the South American low level jet at the east side of the Andes. At the local scale, there is a low-level conditional instability in the previous hours as well as during the occurrence of the TSs above the Huancayo observatory. In addition, the simulation results indicated the possibility of generation of inertial gravity waves in the Amazon basin, associated with geostrophic adjustment which transports energy and moisture into the central Andes plateau and consequently intensifies the thunderstorms above the Mantaro valley. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Potential Uncertainties in the Analysis of Low-Wavenumber Asymmetries Caused by Aliasing Center in Tropical Cyclones
Atmosphere 2019, 10(6), 300; https://doi.org/10.3390/atmos10060300 - 01 Jun 2019
Cited by 1 | Viewed by 905
Abstract
Variations in both symmetric wind components and asymmetric wave amplitudes of a tropical cyclone depend on the location of its center. Because the radial structure of asymmetries is critical to the wave–mean interaction, this study, under idealized conditions, examines the influences of a [...] Read more.
Variations in both symmetric wind components and asymmetric wave amplitudes of a tropical cyclone depend on the location of its center. Because the radial structure of asymmetries is critical to the wave–mean interaction, this study, under idealized conditions, examines the influences of a center location on the radial structure of the diagnosed asymmetries. It has been found that the amplitudes of aliasing asymmetries are mainly affected by the initial symmetric fields. Meanwhile, the radial structure of asymmetry is controlled by the aliasing direction. Sensitivity tests on the location of the center were employed to emphasize the importance of the aliasing direction using angular momentum equations. With a small displacement, the tendencies of azimuthal tangential wind are found to reverse completely when the center shifts to a different direction. This work concludes that the diagnostic results related to asymmetric decomposition should be treated rigorously, as they are prone to inaccuracies, which in turn affect cyclone prediction. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Study on Scale-Selective Initial Perturbation for Regional Ensemble Forecast
Atmosphere 2019, 10(5), 285; https://doi.org/10.3390/atmos10050285 - 21 May 2019
Cited by 1 | Viewed by 1232
Abstract
To improve the skills of the regional ensemble forecast system (REFS), a modified ensemble transform Kalman filter (ETKF) initial perturbation strategy was developed. First, sensitivity tests were conducted to investigate the influence of the perturbation scale on the ensemble spread growth and forecast [...] Read more.
To improve the skills of the regional ensemble forecast system (REFS), a modified ensemble transform Kalman filter (ETKF) initial perturbation strategy was developed. First, sensitivity tests were conducted to investigate the influence of the perturbation scale on the ensemble spread growth and forecast skill. In addition, the scale characteristic of the forecast error was analyzed based on the results of these tests, and a new initial condition perturbation method was developed through scale-selection of the ETKF perturbations, namely, ETKF-SS (scale-selective ETKF). The performances of the ETKF-SS scheme and the original ETKF (hereinafter referred to as ETKF) scheme were tested and compared. The results showed that the large-scale perturbations were much easier to grow than the original ETKF perturbations. In addition, scale analysis of the forecast error showed that the large-scale errors showed significant growth at the upper levels, while the small and meso-scale errors grew fast at the lower levels. The comparison results of the ETKF-SS and the ETKF showed that the ETKF-SS perturbations had more obvious growth than the ETKF perturbations, and the ETKF-SS perturbations in the short-term forecast lead times were more precise than the ETKF perturbations. The ensemble forecast verification results showed that the ETKF-SS ensemble had a larger spread and smaller root mean square error than the ETKF at short forecast lead times, while the probabilistic scores of the ETKF-SS also outperformed those of the ETKF method. In addition, the ETKF-SS ensemble can provide a better precipitation forecast than the ETKF. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Elliptical Structures of Gravity Waves Produced by Typhoon Soudelor in 2015 near Taiwan
Atmosphere 2019, 10(5), 260; https://doi.org/10.3390/atmos10050260 - 10 May 2019
Cited by 7 | Viewed by 1772
Abstract
Tropical cyclones (TCs) are complex sources of atmospheric gravity waves (GWs). In this study, the Weather Research and Forecasting Model was used to model TC Soudelor (2015) and the induced elliptical structures of GWs in the upper troposphere (UT) and lower stratosphere (LS) [...] Read more.
Tropical cyclones (TCs) are complex sources of atmospheric gravity waves (GWs). In this study, the Weather Research and Forecasting Model was used to model TC Soudelor (2015) and the induced elliptical structures of GWs in the upper troposphere (UT) and lower stratosphere (LS) prior to its landfall over Taiwan. Conventional, spectral and wavelet analyses exhibit dominant GWs with horizontal and vertical wavelengths, and periods of 16–700 km, 1.5–5 km, and 1–20 h, respectively. The wave number one (WN1) wind asymmetry generated mesoscale inertia GWs with dominant horizontal wavelengths of 100–300 km, vertical wavelengths of 1.5–2.5 km (3.5 km) and westward (eastward) propagation at the rear of the TC in the UT (LS). It was also revealed to be an active source of GWs. The two warm anomalies of the TC core induced two quasi-diurnal GWs and an intermediate GW mode with a 10-h period. The time evolution of dominant periods could be indicative of changes in TC dynamics. The FormoSat-3/COSMIC (Formosa Satellite Mission-3/Constellation Observing System for Meteorology, Ionosphere, and Climate) dataset confirmed the presence of GWs with dominant vertical wavelengths of about 3.5 km in the UT and LS. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Atmospheric Response to Oceanic Cold Eddies West of Luzon in the Northern South China Sea
Atmosphere 2019, 10(5), 255; https://doi.org/10.3390/atmos10050255 - 08 May 2019
Cited by 1 | Viewed by 1215
Abstract
Using the compositing method, two kinds of sea surface temperature (SST) anomalies associated with mesoscale ocean eddies and their effects on the atmosphere over the northern South China Sea were investigated. We focused on Luzon cold eddies (LCEs), which form during the winter [...] Read more.
Using the compositing method, two kinds of sea surface temperature (SST) anomalies associated with mesoscale ocean eddies and their effects on the atmosphere over the northern South China Sea were investigated. We focused on Luzon cold eddies (LCEs), which form during the winter monsoon and occur repeatedly to the west of Luzon Island, where a SST front exists. Using satellite and reanalysis data, 20 LCEs from 2000–2016 were classified into two types according to their impact on the atmosphere. One type consisted of cold SST anomalies within the eddy interior; subsequent turbulent heat flux and surface wind speed decreased over the cold core, presenting a monopole pattern. The second type comprised SST anomalies on either side of the eddy, which mostly propagated along the SST front. For this type of LCEs, cyclonic eddy currents acting on the SST front led to the SST anomalies. They produced a dipole, with surface wind deceleration and acceleration over negative and positive SST anomalies, respectively, on either side of the eddy’s flank. Dynamically, for both types of LCE, a vertical mixing mechanism appeared to be responsible for the wind anomalies. Moreover, anomalous vertical circulations developed over the LCEs that extended over the whole boundary layer and penetrated into the free atmosphere, leading to an anomalous convective rain rate. Quantitatively, the surface wind speed changed linearly with SST; atmospheric anomalies related to LCEs explained 5%–14% of the total daily variance. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Impact of Cumulus Parameterization on Model Convergence of Tropical Cyclone Destructive Potential Simulation at Grey-Zone Resolutions: A Numerical Investigation
Atmosphere 2019, 10(2), 74; https://doi.org/10.3390/atmos10020074 - 12 Feb 2019
Cited by 1 | Viewed by 1259
Abstract
The Weather Research Forecast model (WRF) is used to examine the destructive potential of tropical cyclone (TC) Shanshan (2006) at various horizontal resolutions (7.5 km–1 km) with different cumulus parameterization (CP) schemes. It is found that the calculated Power Dissipation Index (PDI) increases [...] Read more.
The Weather Research Forecast model (WRF) is used to examine the destructive potential of tropical cyclone (TC) Shanshan (2006) at various horizontal resolutions (7.5 km–1 km) with different cumulus parameterization (CP) schemes. It is found that the calculated Power Dissipation Index (PDI) increases while the size-dependent destructive potential (PDS) decreases as the grid spacing decreases for all CP-scheme simulations, which indicates a weak model convergence in both PDI and PDS calculations. Moreover, it is change of the storm intensity and inner-core size that lead to the non-convergence of PDI and PDS respectively. At a higher resolution, convection becomes more explicitly resolved, which leads to larger diabatic heating. As a result, the radial pressure gradient force (PGF) increases, and the radius of maximum wind (RMW) decreases. The area of strong diabatic heating subsequently becomes closer to the TC center, which further increases the TC intensity and the PGF near the eyewall. With such a positive feedback loop, the PGF increases and the RMW decreases as the resolution increases. Note that a perfect model should converge well in the simulation of both TC intensity and size, and thus converge in the PDS. For some CP experiments, the calculated PDS convergence is relatively strong, but it is a result of offset between the non-convergent simulations of TC intensity and size. In contrast, the Grell–Freitas scheme exhibits a stronger convergence in the simulations of TC intensity and size, although the convergence in PDS is relatively weak, but is closer to the truth. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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Article
Ensemble Sensitivity Analysis-Based Ensemble Transform with 3D Rescaling Initialization Method for Storm-Scale Ensemble Forecast
Atmosphere 2019, 10(1), 24; https://doi.org/10.3390/atmos10010024 - 10 Jan 2019
Cited by 12 | Viewed by 1621
Abstract
In order to further investigate the influence of ensemble generation methods on the storm-scale ensemble forecast (SSEF) system, a new ensemble sensitivity analysis-based ensemble transform with 3D rescaling (ET_3DR_ESA) method was developed. The Weather Research and Forecasting (WRF) Model was used to numerically [...] Read more.
In order to further investigate the influence of ensemble generation methods on the storm-scale ensemble forecast (SSEF) system, a new ensemble sensitivity analysis-based ensemble transform with 3D rescaling (ET_3DR_ESA) method was developed. The Weather Research and Forecasting (WRF) Model was used to numerically simulate a squall line that occurred in the Jianghuai region in China on 12 July 2014. In this study, initial perturbations were generated via ET_3DR_ESA, and the ensemble forecast performance was compared to that of the dynamical downscaling (Down) method and the ensemble transform with 3D rescaling (ET_3DR) method. Results from a set of experiments indicate that ET_3DR_ESA linked to multi-scale environmental fields generates initial perturbations that can not only capture analysis uncertainties, but also match the actual synoptic conditions. Such perturbations produce faster ensemble spread growth, lower root-mean-square error, and a lower percentage of outliers, especially during the peak period of the squall line. In addition, ET_3DR_ESA can effectively reduce the energy dissipation on different scales through the analysis of the power spectrum. Moreover, the intensity and distribution forecasts of heavy rainfall from the ET_3DR_ESA ensemble forecast system were demonstrated to better match the observation. Furthermore, according to results of the relative operating characteristic (ROC) test, Brier score (BS), and equitable threat score (ETS), ET_3DR_ESA significantly improved the forecast skills for heavy rain (15–30 mm/12 h) and extreme rain (>30 mm/12 h), which are critical to the realization of accurate storm-scale system precipitation forecasts. In general, these results suggest that ET_3DR_ESA can be effectively applied to SSEF systems. Full article
(This article belongs to the Special Issue Advancements in Mesoscale Weather Analysis and Prediction)
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