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A nocturnal maximum in rainfall and thunderstorm activity over the central Great Plains has been widely documented, but the mechanisms for the development of thunderstorms over that region at night are still not well understood. Elevated convection above a surface frontal boundary is one explanation, but this study shows that many thunderstorms form at night without the presence of an elevated frontal inversion or nearby surface boundary. This study documents convection initiation (CI) events at night over the central Great Plains from 1996 to 2015 during the months of April–July. Storm characteristics such as storm type, linear system orientation, initiation time and location, and others were documented. Once all of the cases were documented, surface data were examined to locate any nearby surface boundaries. The event’s initiation location relative to these boundaries (if a boundary existed) was documented. Two main initiation locations relative to a surface boundary were identified: on a surface boundary and on the cold side of a surface boundary; CI events also occur without any nearby surface boundary. There are many differences among the different nocturnal CI modes. For example, there appear to be two main peaks of initiation time at night: one early at night and one later at night. The later peak is likely due to the events that form without a nearby surface boundary. Finally, a case study of three nocturnal CI events that occurred during the Plains Elevated Convection At Night (PECAN) field project when there was no nearby surface boundary is discussed.

Lightning channel morphology depends on the thunderstorm cloud charge structure, which in turn is influenced by the thunderstorm dynamics. In this paper, based on three‐dimensional radiation source localization data from the Lightning Mapping Array and radar‐based data, our analysis shows that the overall morphology and detailed morphology of the lightning channel correspond to different eddy dissipation rate (EDR) characteristics. Lightning with complex channel morphology occurs in regions with large EDRs. In single lightning events, channels that extend directly within a certain height range without significant bifurcation and turning tend to propagate in the direction of decreasing EDRs, while channel bifurcations and turns usually occur in regions with large radial velocity gradients and large EDRs. This study shows the relationship between channel morphology and thunderstorm dynamics and provides a new method for the direct application of channel‐level localization data to understand thunderstorm dynamics characteristics. Plain Language Summary Turbulence in thunderstorms affects the charge distribution, which in turn affects the lightning channel morphology. Thus, the lightning channel morphology can reflect the characteristics of turbulence. The current understanding of the correlation between the two is still limited to the relationship between macroscopic thunderstorm dynamic characteristics and lightning activity. In this paper, the relationship between the morphology of the lightning channel and turbulence characteristics is investigated based on the Lightning Mapping Array (LMA) localization data and the cube root of the eddy dissipation rate (EDR) estimated from KABX radar‐based data. The turbulence strength affects the overall morphology of lightning, and lightning with complex morphology tends to occur in regions with large EDRs. In single lightning events, channels extending directly within a certain altitude range tend to propagate in the direction of decreasing EDRs, and lightning channel bifurcation or turning tends to occur in regions with large EDRs. This paper establishes the relationship between thunderstorm electricity and thunderstorm dynamics by using lightning channel morphology as a bridge and provides a new method for the direct application of channel‐level localization data to understand thunderstorm dynamics characteristics. Key Points The morphology of lightning channels can reflect the distribution of turbulence intensity, and a certain correlation between the two exist Directly extended lightning channels tend to propagate in the direction of decreasing eddy dissipation rates The location of the channel bifurcations or turns often corresponds to regions with high eddy dissipation rates

Rawinsonde measurements from Central Europe were evaluated to investigate environments associated with lightning. The study compared lightning and non‐lightning profiles, pre‐ and post‐convective profiles, and varying lightning flash rates. In total, 137,501 quality‐controlled measurements from 2006 to 2018 were used, along with 327 convective parameters. Their performance was evaluated using the area under the curve (AUC). The Lifted Index (LI) and its effective version (LI_eff) are the most robust predictors of lightning. Other useful parameters are CAPE in a hail growth zone (CAPE_HGL), cold cloud depth (Cold_layer), and equilibrium level temperature and height (EL_tmp, EL_hgt). 1–4 km relative humidity (RH_14 km) is important for thunderstorm development in warm environments, while in the cold season lightning is associated with stronger atmospheric flow. Most thunderstorms form with CIN greater than −100 J kg−1. Non‐lightning but unstable profiles show limited instability in the convective cloud layer below −10°C, highlighting the role of buoyancy in subfreezing temperatures.

Most of the rainfall in southern Australia is associated with cyclones, cold fronts, and thunderstorms, and cases when these weather systems co-occur are particularly likely to cause extreme rainfall. Rainfall declines in some parts of southern Australia during the cool half of the year in recent decades have previously been attributed to decreases in the rainfall from fronts and/or cyclones, while thunderstorm-related rainfall has been observed to increase, particularly in the warm half of the year. However, the co-occurrence of these systems, particularly the co-occurrence of cyclones or fronts with thunderstorms, can be very important for rainfall in some areas, particularly heavy rainfall, and changes in the frequency of these combined weather systems have not been previously assessed. In this paper we show that the majority of the observed cool season rainfall decline between 1979–1996 and 1997–2015 in southeast Australia is associated with a decrease in the frequency of fronts and cyclones that produce rainfall, while there has simultaneously been an increase in the frequency of cold fronts and thunderstorms that do not produce rainfall in some regions. Thunderstorm rainfall has increased in much of southern Australia, particularly during the warm half of the year, including an increase in rainfall where a thunderstorm environment occurs at the same time as a cyclone or front.

Terrestrial gamma‐ray flashes (TGFs) are short bursts of intense gamma radiation associated with lightning discharges. Although thousands of TGFs have been observed from space, TGFs detected at ground level, known as downward TGFs, are still very limited, and their relationship with lightning discharge processes remains elusive. Here we report a special type of strong negative lightning stroke, termed energetic compact stroke (ECS), in winter thunderstorms in Japan, and provide strong evidence that ECSs are consistently associated with downward TGFs. Based on this relationship, we successfully identified three new downward TGFs by the observations of ECSs. Further, 12 out of 19 (63%) of downward TGFs analyzed in this paper were associated with ECSs, indicating that ECSs are the major source of downward TGFs in winter thunderstorms in Japan. These findings open up the possibility of remotely monitoring a large fraction of downward TGFs with simple lightning observations. Plain Language Summary Terrestrial gamma‐ray flashes (TGFs) are the most intense natural sources of gamma‐ray emissions on Earth. It is well established that TGFs are coincident with lightning discharges, but it is still largely unclear what lightning discharge processes can produce TGFs and under what circumstances. In this paper, we provide strong evidence that a special type of negative lightning stroke, referred to as “energetic compact stroke” (ECS), in winter thunderstorms is consistently associated with downward TGFs. This finding makes it possible for future studies to investigate TGF mechanisms by simply observing ECSs. We also found that a large portion, 63% in this study, of downward TGFs were associated with ECSs. This unexpectedly high percentage opens up the possibility of remotely monitoring downward TGFs over wide areas simply through the detection of lightning. Key Points A special type of lightning stroke named “energetic compact stroke” (ECS) is always coincident with downward TGFs Three new downward TGFs were identified by the observations of ECSs More than 60% of downward TGFs in winter thunderstorms in Japan are associated with ECSs

Atmospheric rivers (ARs) are well known for their contributions to precipitation and flooding across the U.S. The present study explores the relationship between ARs and the potential for severe thunderstorms and tornadoes over the U.S. in both the warm and cool seasons during a 20‐year period from 2004 to 2023. A statistical analysis of severe thunderstorm and tornado warnings issued by the National Weather Service and AR events demonstrates that a majority of warnings over the Southeastern and Eastern U.S. are associated with ARs, especially tornado warnings. Conversely, given an AR event, a minority of AR events feature severe thunderstorm warnings or tornado warnings, with higher fractions in the warm season except for tornado warnings over the Southeastern U.S. It is concluded that ARs appear as a practically necessary, but not sufficient, factor related to the potential for severe convective storms, especially the issuance of tornado warnings in the cool season.

Using a clustering algorithm based on cloud‐to‐ground (CG) lighting data, 72,974 thunderstorms were identified and tracked in the middle reaches of the Yangtze River Basin from May to September of 2016–2020. Thunderstorms predominantly occur in the southeast region and move to the northeast at a speed of 16–64 km/hr. Most thunderstorms have short durations (98.3%, ≤3 hr) and low CG flash frequencies (90.0%, ≤64). Thunderstorms with longer durations are mainly triggered near the mountains and tend to occur (end) earlier (later) in the afternoon (evening). The peak composite reflectivity (CR) corresponding to CG flashes from all thunderstorms is 50 dBZ. Approximately 70% (20%) of CG flashes occur in convective (stratiform) areas. The first CG flash of a thunderstorm tends to occur in convective areas with a higher CR than that of the last CG flash. The average and maximum CRs of CG flashes increase significantly with thunderstorm duration. Plain Language Summary Thunderstorms are known as a type of weather system that is typically accompanied by the presence of lighting and other hazardous weather (high winds, heavy rain, hail and tornadoes). Cloud‐to‐ground (CG) lighting produced by thunderstorms is a highly dangerous weather phenomenon that occurs between a thundercloud and the ground and often causes wildfires, explosions and severe damage to buildings. The middle reaches of the Yangtze River Basin in China are a transition zone between plateaus and plains, with dense urban agglomerations, rivers and lakes. However, thunderstorm activity in such complex underlying surfaces is poorly understood. Based on ground‐based radar and lightning observations, the statistical characteristics of thunderstorm activity in this region during the warm seasons (May to September) of 2016–2020 are analyzed using a lightning clustering method. The CG lighting number, area and displacement of thunderstorms increase with thunderstorm duration. Thunderstorms that last longer are mostly triggered near the mountains and often start earlier in the afternoon and end later in the evening. In addition, CG lighting produced by thunderstorms is associated with high radar echo intensity. These findings are useful for improving the nowcasting of lightning and other hazardous weather caused by thunderstorms. Key Points The cloud‐to‐ground (CG) flash number, area, displacement, etc., of thunderstorms based on lightning data change with increasing thunderstorm duration Thunderstorms with longer durations, mostly triggered near the mountains, occur earlier in the afternoon and end later in the evening Radar echo characteristics of CG flashes from thunderstorms with different durations show certain regularities

This study presents the research of thunderstorms in Slovakia using records of thunderstorm days from weather observation stations from 1965 to 2023, as well as radar data, and data from lightning detection systems from 2010 to 2023. An algorithm was developed to identify thunderstorms using radar and lightning data. The temporal distribution of thunderstorms is examined across annual, seasonal, daily, and hourly timescales. Additionally, we focus on the spatial distribution of thunderstorms, where lightning data according to a proposed algorithm were used. The occurrence of thunderstorms is also analyzed in the light of macrosynoptic types, according to a 28-class classification of the Slovak Hydrometeorological Institute. The results show that close thunderstorms (within 3 km of a given location) in Slovakia occur on average on 15 days a year, most frequently in the summer months of June and July, and primarily in the late afternoon between 3 and 5 p.m. Central European Summer Time (CEST). The spatial distribution of thunderstorms in Slovakia is non-homogeneous, with an increased occurrence in Central Slovakia, particularly in the area of Muránska Planina, Stolické, and Volovské Vrchy Mts. Conversely, the fewest thunderstorms occur in the westernmost part of the territory. Severe thunderstorms are most numerous in the Gemer region. The occurrence of thunderstorms is significantly influenced by synoptic types, with the most favorable conditions associated with types B (trough over Central Europe), Bp (traveling trough), C (cyclone over Central Europe), and Cv (upper cyclone). In recent decades, significant decrease in the number of thunderstorm days per year has been observed. This may be due to the observed decreasing trend of cyclonic synoptic situations in Europe, where a substantial number of thunderstorms occur.

Nepal has a very large topographical variation; this elevation change has a major influence on lightning occurrence and human casualties. The Himalayan peaks cover the northern part of Nepal with low population density, the middle is covered by hills with intermediate density, and the southern plain with the greatest density. This study will leverage lightning detection by Vaisala's Global Lightning Dataset GLD360 network with a recent detailed compilation of lightning casualties from 2011 through 2020. Over one million lightning strokes per year were detected from 2016 through 2020. Stroke density is least over high elevations to the north, moderate in hilly regions, and very frequent over the south. The thunderstorm season begins in March and ceases by August after the annual monsoon cycle. Of all the natural disasters, lightning has been recorded to be the second highest killer after earthquakes. The Ministry of Home Affairs reports an average of 103 lightning deaths per year. The fatality rate of 3.8 deaths million −1  year −1 is highest among the South Asian countries. Fatalities over high mountains are rare, with most casualties over the center of Nepal. Lightning Fatality Risk is not a good indicator of the fatalities that occur in a district. Highlights Lightning occurrence and fatalities are most frequent in districts along the southern border, and least in the northern high-elevation districts Lightning occurrence and fatalities are concentrated in the pre-monsoon and monsoon months Districts with the largest stroke densities often do not coincide with the districts with the greatest fatality rates per million people

Previous total lightning climatology studies using Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) observations were reported at coarse resolution (0.5°) and employed significant spatial and temporal smoothing to account for sampling limitations of TRMM’s tropical to subtropical low-Earth-orbit coverage. The analysis reported here uses a 16-yr reprocessed dataset to create a very high-resolution (0.1°) climatology with no further spatial averaging. This analysis reveals that Earth’s principal lightning hotspot occurs over Lake Maracaibo in Venezuela, while the highest flash rate density hotspot previously found at the lower 0.5°-resolution sampling was found in the Congo basin in Africa. Lake Maracaibo’s pattern of convergent windflow (mountain–valley, lake, and sea breezes) occurs over the warm lake waters nearly year-round and contributes to nocturnal thunderstorm development 297 days per year on average. These thunderstorms are very localized, and their persistent development anchored in one location accounts for the high flash rate density. Several other inland lakes with similar conditions, that is, deep nocturnal convection driven by locally forced convergent flow over a warm lake surface, are also revealed. Africa is the continent with the most lightning hotspots, followed by Asia, South America, North America, and Australia. A climatological map of the local hour of maximum flash rate density reveals that most oceanic total lightning maxima are related to nocturnal thunderstorms, while continental lightning tends to occur during the afternoon. Most of the principal continental maxima are located near major mountain ranges, revealing the importance of local topography in thunderstorm development.