Severe Weather Research Papers - Academia.edu (original) (raw)

2025, Monthly Weather Review

The evolution of the wind field beyond the radius of maximum winds is studied for 18 Atlantic tropical cyclones (TCs) with 989 research and reconnaissance flight legs. Inner core strength, defined as the storm relative mean tangential wind from 65 to 140 km from the circulation center for a given flight leg, is shown to be linearly correlated with tropical cyclone intensity. Inner core strengthening coincides with deepening, but as a hurricane decays, the inner core may exhibit a wider range of behavior. During an eyewall replacement cycle inner core strength and intensity become out of phase. Inner core strength tends to be axisymmetric as no quadrant maintains a higher inner core strength than the other quadrants for more than a day. Increases of inner core strength occur throughout the entire 65-140-km radial distance and, thus, are not due to the higher winds found in rainbands alone. The authors speculate that inner core strength, being relatively close to the circulation center, responds efficiently to heat and momentum sources in the eyewall. The behavior differences between inner core strength in these hurricanes and outer core strength in typhoons discussed in earlier works are chiefly a function of distance from the eyewall and appear consistent in light of currently accepted theoretical arguments.

2025, 22nd Conference on …

2025, IEEE Transactions on Visualization and Computer Graphics

A common approach to sampling the space of a prediction is the generation of an ensemble of potential outcomes, where the ensemble's distribution reveals the statistical structure of the prediction space. For example, the US National Hurricane Center generates multiple day predictions for a storm's path, size, and wind speed, and then uses a Monte Carlo approach to sample this prediction into a large ensemble of potential storm outcomes. Various forms of summary visualizations are generated from such an ensemble, often using spatial spread to indicate its statistical characteristics. However, studies have shown that changes in the size of such summary glyphs, representing changes in the uncertainty of the prediction, are frequently confounded with other attributes of the phenomenon, such as its size or strength. In addition, simulation ensembles typically encode multivariate information, which can be difficult or confusing to include in a summary display. This problem can be overcome by directly displaying the ensemble as a set of annotated trajectories, however this solution will not be effective if ensembles are densely overdrawn or structurally disorganized. We propose to overcome these difficulties by selectively sampling the original ensemble, constructing a smaller representative and spatially well organized ensemble. This can be drawn directly as a set of paths that implicitly reveals the underlying spatial uncertainty distribution of the prediction. Since this approach does not use a visual channel to encode uncertainty, additional information can more easily be encoded in the display without leading to visual confusion. To demonstrate our argument, we describe the development of a visualization for ensembles of tropical cyclone forecast tracks, explaining how their spatial and temporal predictions, as well as other crucial storm characteristics such as size and intensity, can be clearly revealed. We verify the effectiveness of this visualization approach through a cognitive study exploring how storm damage estimates are affected by the density of tracks drawn, and by the presence or absence of annotating information on storm size and intensity.

2025, Miscellanea geographica

The research presents a comparison between two methods which are used to identify days on which there are thunderstorms (TDs) in Poland. SYNOP and PERUN lightning network data from the Institute of Meteorology and Water Management (IMGW-PIB) for the period 2002-2020 were used to determine and compare the changes in the number of TDs. To determine the number of TDs using the PERUN data, an appropriate method needed to be created which would allow for the closest possible reference to human perception in relation to lightning. A buffer with a radius of 15 km was used, and TDs were counted when there was at least one flash within the buffer circle. Measurements performed by observers are sometimes not homogeneous and are prone to errors, and thus underestimate the actual number of TDs. As a result of the analysis, the average number of TDs in Poland was found to be 26 (SYNOP) and 30 (PERUN) per year.

2025

Doppler radar information is used to identify features related to the radial wind field and signals such as mesovortex and other mesoscale wind structures. Automation of some processes can improve the forecasters' ability to issue early... more

2025, Journal of Operational Meteorology

Kennedy Space Center and Cape Canaveral Air Force Station (CCAFS) are at risk from severe weather. Strong winds, hail, and tornadoes can injure individuals and cause costly damage to structures if not properly protected. This is important because central Florida is the thunderstorm capital of the United States and has the highest tornado density in the country, albeit a smaller percentage than the national average of these tornadoes is of significant intensity. The 45th Weather Squadron (45WS) severe weather forecasts are used by managers to determine if they need to schedule activities (such as working on gantries) or protect property (such as a vehicle on a pad). Missed desired lead-time and false-alarm rate statistics show that severe weather in east-central Florida is difficult to forecast during the warm season (May-September). The 45WS tasked the Applied Meteorology Unit (AMU) to develop a locally tuned tool to predict the probability of warm-season severe weather using a 24-yr climatological database from the 1500 UTC (1100 EDT) CCAFS radiosondes (KXMR). The results indicate the proper use of certain stability indices and parameters based on the late-morning KXMR soundings can improve the forecaster's ability to identify days with a severe weather threat. The AMU calculated a total severe potential (TSP) by integrating the important parameters for every 1500 UTC sounding and other factors in the 24-yr database and compared the TSP to reported severe weather occurrences on each day with a sounding. Logistic regression was used to convert the TSPs to probability of severe weather as a first guess tool for the 45WS forecasters.

2025, Weather and Forecasting

A tropical cyclone (TC) wind speed probability forecast product developed at the Cooperative Institute for Research in the Atmosphere (CIRA) and adopted by the National Hurricane Center (NHC) is evaluated for U.S. land-threatening and landfalling events over four hurricane seasons from 2004 to 2007. A key element of this work is the discernment of risk associated with the interval forecast probabilities for the three wind speed categories (i.e., 34, 50, and 64 kt, where 1 kt = 0.52 m s−1). A quantitative assessment of the interval probabilities (0–12, 12–24, 24–36, 36–48, 48–72, 72–96, and 96–120 h) is conducted by converting them into binary (yes–no) forecasts using decision thresholds that are selected using the true skill statistic (TSS) and the Heidke skill score (HSS). The NHC product performs well as both the HSS and TSS demonstrate skill out to the 48–72- and 72–120-h intervals, respectively. Overall, reliability diagrams and bias scores indicate that the NHC product has a te...

2025, IEEE Transactions on Power Systems

A new predictive risk-based framework is proposed
to increase power distribution network resiliency by improving
operator understanding of the status of the grid. This paper
expresses the risk assessment as the correlation between
likelihood and impact. The likelihood is derived from the
combination of Naive Bayes learning and Jenks natural breaks
classifier. The analytics included in a GIS platform fuse together
a massive amount of data from outage recordings and weather
historical databases in just one semantic parameter known as
failure probability. The financial impact is determined by a time
series-based formulation that supports spatiotemporal data from
fault management events and customer interruption cost. Results
offer prediction of hourly risk levels and monthly accumulated
risk for each feeder section of a distribution network allowing for
timely tracking of the operating condition.

2025, Monthly Weather Review

As part of NOAA’s Warn-on-Forecast (WoF) initiative, a multiscale ensemble-based assimilation and prediction system is developed using the WRF-ARW model and DART assimilation software. To evaluate the capabilities of the system, retrospective short-range probabilistic storm-scale (convection allowing) ensemble analyses and forecasts are produced for the 27 April 2011 Alabama severe weather outbreak. Results indicate that the storm-scale ensembles are able to analyze the observed storms with strong low-level rotation at approximately the correct locations and to retain the supercell structures during the 0–1-h forecasts with reasonable accuracy. The system predicts the low-level mesocyclones of significant isolated tornadic supercells that align well with the locations of radar-derived rotation. For cases with multiple interacting storms in close proximity, the system tends to produce more variability in mesocyclone forecasts from one initialization time to the next until the observa...

2025, J. Fluid Mech

The spreading and diffusion of two-dimensional vortices subject to weak, external, random strain fields is examined. The response to such a field of given angular frequency depends on the profile of the vortex and can be calculated numerically. An effective diffusivity can be determined as a function of radius and may be used to evolve the profile over a long time scale, using a diffusion equation that is both nonlinear and nonlocal. This equation, containing an additional smoothing parameter, is simulated starting with a Gaussian vortex. Fine scale steps in the vorticity profile develop at the periphery of the vortex and these form a vorticity staircase. The effective diffusivity is high in the steps where the vorticity gradient is low: between the steps are barriers characterised by low effective diffusivity and high vorticity gradient. The steps then merge before the vorticity is finally swept out and this leaves a vortex with a compact core and a sharp edge. There is also an increase in the effective diffusion within an encircling surf zone. In order to understand the properties of the evolution of the Gaussian vortex, an asymptotic model first proposed by Balmforth, Llewellyn Smith and Young (J. Fluid Mech. 426, 95-133, 2001) is studied. The model is based on a vorticity distribution that consists of a compact vortex core surrounded by a skirt of relatively weak vorticity. Again simulations show the formation of fine scale vorticity steps within the skirt, followed by merger. The diffusion equation we develop has a tendency to generate vorticity steps on arbitrarily fine scales; these are limited in our numerical simulations by smoothing the effective diffusivity over small spatial scales.

2025, HAL (Le Centre pour la Communication Scientifique Directe)

This paper reports on an experimental investigation of the stability of a baroclinic front, as generated by the spinup of a differentially rotating lid at the surface of a rotating two-layer fluid. In contrast to formerly reported experiments, we consider miscible fluids in a relatively wide annular tank. In the parameter space set by rotational Froude number and dissipation (i.e. ratio of spin-down time to disk rotation time), different flow regimes are observed, ranging from axisymmetric to irregular baroclinic instable flows. These regimes adjoin the regimes found for immiscible fluids by in a small device. Differences are the baroclinic unstable regime for lower Froude number than reported by suggesting Sakai Rossby-Kelvin waves and the formation of vortices. Observations suggest spontaneous emission of inertia gravity waves, which interact with the large-scale baroclinic wave and lead to intense mixing and the rapid formation of intense cyclonic vortices. Cette article représente une étude expérimentale sur l'instabilité d'un front barocline qui a été généré par la mise en rotation différentielle d'un fluide bi-couche. Contrairement à d'autres expériences précédentes de ce type, nous considérons des fluides miscibles dans une cuve relativement grande. Dans l'espace déterminée par le nombre de Froude et le nombre de dissipation, nous observons différents régimes, allant des écoulements axisymétriques aux écoulements instables et irréguliers. Ces régimes adjoignent les régimes obtenus pour un fluide bicouche immiscibles par dans une cuve petite. Différente est l'apparition du régime barocline pour des nombres de Froude plus bas, suggérant les ondes Rossby-Kelvin de Sakai, et la formation des tourbillons. Les observations suggèrent l'émission spontanée des ondes inertie-gravitée lesquelles interagissent avec l'onde barocline à grande échelle, et ainsi déclenche du mélange et la formation rapide des tourbillons intenses.

2025, HAL (Le Centre pour la Communication Scientifique Directe)

2025, Journal of Physical Oceanography

Three autonomous profiling Electromagnetic Autonomous Profiling Explorer (EM-APEX) floats were air deployed one day in advance of the passage of Hurricane Frances (2004) as part of the Coupled Boundary Layer Air–Sea Transfer (CBLAST)-High field experiment. The floats were deliberately deployed at locations on the hurricane track, 55 km to the right of the track, and 110 km to the right of the track. These floats provided profile measurements between 30 and 200 m of in situ temperature, salinity, and horizontal velocity every half hour during the hurricane passage and for several weeks afterward. Some aspects of the observed response were similar at the three locations—the dominance of near-inertial horizontal currents and the phase of these currents—whereas other aspects were different. The largest-amplitude inertial currents were observed at the 55-km site, where SST cooled the most, by about 2.2°C, as the surface mixed layer deepened by about 80 m. Based on the time–depth evolutio...

2025

. Available online at: www.ccafs.cgiar.org CCAFS Workshop Reports aim to disseminate interim climate change, agriculture and food security research and practices and stimulate feedback from the scientific community.

2025

Rapid increases in total lightning activity have been shown to be an indicator of severe weather potential within a thunderstorm. The current lightning jump algorithm (LJA) is an objective, statistically based algorithm used to determine when these rapid increases in total lightning are observed within a given storm. This algorithm was constructed using three-dimensional lightning data from lightning mapping arrays in Alabama, Oklahoma, STEPS, and Washington D.C. Offline evaluation of the research algorithm from 2002 -2011 has yielded a probability of detection (POD) of 65% and a false alarm ratio (FAR) of 46%. Further steps to transition the LJA to a real-time operational algorithm were taken in 2012 and 2013 which resulted in similar POD, larger lead times and notably larger FAR than previous studies. Both of these studies used Storm Data from the National Climatic Data Center (NCDC) for validation. Inconsistencies in the quality and reliability of storm reports in verification have been noted in the literature. One aspect is that not all severe events are reported, leading to the likelihood that the traditional verification methods will result in an elevated FAR due to an incomplete database. A fair assessment of the lightning jump algorithm requires an accurate and precise reporting of severe weather occurrences in both time and space. The Severe Hazards Analysis and Verification Experiment (SHAVE) is an ongoing project that is part of the NOAA Hazardous Weather Testbed -Experimental Warning Program at National Severe Storm Laboratory to collect high temporal and spatial resolution report data from thunderstorms including hail size, wind damage, and flash flooding. During the 2012 and 2013 real-time Lightning Jump test, SHAVE data was collected on several cases within the Alabama, Oklahoma, and Washington D. C. domains. Because of its widespread availability, good coverage and proven severe storm proxies, radar will also be employed as part of this enhanced verification process. This study will investigate utilizing SHAVE and radar data with case studies from the larger real-time LJA database to explore enhanced verification techniques for the LJA and demonstrate lightning's value to tip the scales in the warning decision framework when combined with operational radar data.

2025, arXiv (Cornell University)

2025, Piracicaba Meteorológica

Este artigo apresenta uma revisão da análise inicial do tornado registrado no bairro Campestre, em Piracicaba, interior do estado de São Paulo, Brasil, durante o crepúsculo vespertino do dia 31 de janeiro de 2025. O presente estudo corrige informações publicadas anteriormente em 23 de fevereiro de 2025, especialmente no que diz respeito à localização exata do toque do solo, agora indicada como uma área vegetal no entorno do Ribeirão do Enxofre, no Campestre, e às características físicas do fenômeno. Com base em análises de vídeo, referências geográficas fixas e modelagens via Google Earth, foi possível refinar a trajetória estimada e reafirmar a classificação do evento como um tornado F0/EF0. Também é discutida a possibilidade de o fenômeno ter sido um tornado de vórtices múltiplos (multi-vortex).

2025, Research Square (Research Square)

The paper focuses on the evaluation of hailstorms' and thunderstorms winds' events in the United States of America, in the period from 1996 to 2022, from the marked spatio-temporal self-exciting point processes point of view. The aim of the present article is the assessment and description of the spatio-temporal spontaneous and reproducing activity of severe hailstorms' and thunderstorms winds' processes. Though possibly the spatio-temporal dynamics of the underlying spatio-temporal process are not exactly evaluable according to the self-exciting processes' theoretical framework, the present application shows how the spatiotemporal pattern is well-fitted and clearly explainable, according to the flexible semi-parametric ETAS model fitting.

2025

This study presents a novel approach to detecting early signals of planetary instability by applying fractal metrics to Earth's energy and mass fields. Using z-score normalized GRACE gravity anomalies and MERRA-2 net shortwave surface radiation data (SWGNT), we compute residuals across zonal latitude bands. These residuals represent divergence between incoming solar energy and Earth's capacity to redistribute mass. When analyzed with fractal tools such as the Lyapunov exponent, these signals reveal coherent high-volatility zones. Our most significant finding emerges from the Ferrell-Polar North (58-62°N) latitude band, where we observe concurrent peaks in gravity Lyapunov exponents (>1) and radiation residuals. The longitudes of highest volatility-near-150°,-50°, and +160°-correspond to critical geophysical regions: the Bering Sea, the Greenland-Iceland convergence zone, and North Atlantic AMOC-linked regions, and the permafrost region of Eastern Siberia in Magadan Oblast/Yakutia region. This coherence suggests not isolated anomalies, but a trans-spheric planetary-scale rebalancing process involving atmospheric, hydrospheric, and lithospheric coupling. We propose that these zones may function as resonant nodes of instability and energy redistribution, and that fractal volatility is a meaningful indicator of approaching systemic tipping points. We also propose that fractal metrics in these zones may serve as leading indicators of both extreme weather and climate events. Closer examination and cross referencing to weather and climate time series data may prove conclusive.

2025, Piracicaba Meteorológica

Piracicaba, localizada no interior do estado de São Paulo, foi palco de dois eventos significativos de vento intenso em um curto intervalo de tempo: o vendaval de 3 de novembro de 2023 e o de 24 de agosto de 2024. Este estudo tem como... more

2025, Bulletin of the American Meteorological Society

The state of knowledge regarding trends and an understanding of their causes is presented for a specific subset of extreme weather and climate types. For severe convective storms (tornadoes, hailstorms, and severe thunderstorms), differences in time and space of practices of collecting reports of events make using the reporting database to detect trends extremely difficult. Overall, changes in the frequency of environments favorable for severe thunderstorms have not been statistically significant. For extreme precipitation, there is strong evidence for a nationally averaged upward trend in the frequency and intensity of events. The causes of the observed trends have not been determined with certainty, although there is evidence that increasing atmospheric water vapor may be one factor. For hurricanes and typhoons, robust detection of trends in Atlantic and western North Pacific tropical cyclone (TC) activity is significantly constrained by data heterogeneity and deficient quantifica...

2025, Water

The paper investigates weather-related fatalities over the territory of the Czech Republic in the 100-year period from 1921 to 2020. The unique database, created from documentary evidence (particularly newspapers), includes, for each deadly event, information about the weather event, the fatality itself, and related circumstances. A total of 2729 fatalities were detected during the 100-year period and were associated with various weather categories including frost (38%), convective storms (19%), floods (17%), fog (11%), snow and glaze ice (8%), windstorms (5%), and other inclement weather (2%). A detailed analysis was performed for each individual category. Fatalities occurred throughout the country, with a main maximum in winter (January) and a secondary maximum in summer (July), corresponding to the occurrence of extreme weather. Deaths were mainly interpreted as direct, caused by freezing to death/hypothermia or drowning, and occurred in the afternoon and at night in open country...

2025, Boundary-Layer Meteorology

The lower limit on the drag coefficient under hurricane force winds is determined by the break-up of the air-sea interface due to Kelvin-Helmholtz instability and formation of the two-phase transition layer consisting of sea spray and air bubbles. As a consequence, a regime of marginal stability develops. In this regime, the air-sea drag coefficient is determined by the turbulence characteristics of the two-phase transition layer. The upper limit on the drag coefficient is determined by the Charnock-type wave resistance. Most of the observational estimates of the drag coefficient obtained in hurricane conditions and in laboratory experiments appear to lie between the two extreme regimes: wave resistance and marginal stability.

2025

Observational information from approximately 100 aircraft flight missions (533 radial legs) flown into and out of twenty-two hurricanes on forty-one storm days over a twelve year period (1957-1967. 1969) by aircraft of the NOAA's Research Flight Facility is presented for general reference of those who have a need or interest in inner hurricane information. Most flight missions were made between the 900 and 500 mb levels. 41 missions are available in the upper troposphere. A list of previous research papers on this flight information is also given. 1

2025

The paper starts by discussing the historical severe hailstorm data in Spain and data compilation. The discussion extends then onto the application a two-dimensional Gaussian kernel smoother to the European Severe Weather Data (ESWD) severe hail reports to derive the empirical severe hailstorm climatology in Spain. Severe hailstorms and events are then simulated based on the empirical hailstorm climatology. Simulation results are compared to ESWD reports and other independent studies. Simulation of hailstorm parameters and development of vulnerability functions for assessing severe hailstorm losses are also described.

2025, 31st Conference on Severe Local Storms

On 21 March 2022, multiple supercells produced 17 tornadoes in North Texas. The strongest tornado was an EF-3 which occurred in Jack County and struck the City of Jacksboro. The tornado traveled 55.6 km (34.5 miles) and damaged or destroyed dozens of wood-framed residences, an elementary school, and high school. Large span gymnasiums at both schools sustained severe damage. This paper will summarize observations from our damage survey including a discussion of the Enhanced Fujita Scale.

2025, Atmospheric Research

This study aims to perform observational data analyses, including European Centre for Medium-Range Weather Forecasts data, radar reflectivity, rainfall data, and numerical simulations with the Weather Research and Forecasting model to examine the orographic effects on a localized heavy rainfall episode which produced up to 204 and 161.5 mm over southwestern Taiwan on 27 and 28 June 2008, respectively. We found that the continuous inland-transport of moist air or inland-movement of convection from the nearby ocean to southwestern Taiwan occur on both days. The orographic lifting on the moist air and convection generates heavy rainfall over sloped areas on 27 June when the relatively fast southwesterly low-level wind prevails (~10 m s -1 ). The cool air near the foothill facilitates the new development of convection on the upstream side of the old convection over the slope and produces heavy rainfall over lowlands near the foothill. On 28 June, the convection, which is embedded in a relatively slow southwesterly moist airflow, is enhanced over the low-level convergence areas in the lowlands due to the prevailing southwesterly wind. This wind is deflected by the orographic effect and produces heavy rainfall. In addition, the cool air from sloped areas enhances the offshore flow which interacts with the prevailing wind to strengthen the low-level convergence over lowlands and coasts.

2025, Atmospheric Research

The effects of orographic lifting and blocking on a heavy rainfall event with an accumulation of 631.5 mm on 11 October 2009 over the Lan-Yang Plain (LYP) in northeastern Taiwan during the northeasterly monsoon season were studied by performing observational data analyses and numerical simulations using the Weather Research and Forecasting (WRF) model. The synoptic environment included a low-level easterly wind over the East China Sea and a southeasterly wind over the western North Pacific Ocean which produced convergence areas leading to the heavy rainfall event. The mesoscale features and the orographic lifting and blocking effects on the production and maintenance of the heavy orographic rainfall without the direct influence of the typhoon's circulations during the northeasterly monsoon season in fall were first investigated here. Due to orographic blocking on the prevailing easterly wind over the western LYP, the induced near-surface northeasterly flow containing moist airstream was lifted over the windward (south) side of the LYP and rainfall was enhanced in situ. Meanwhile, the precipitating system was embedded in a weak middle-level flow with the wind reversing its direction over the windward side of the LYP, resulting in a quasi-stationary system over the slope area. Furthermore, the prevailing easterly wind ascended over the coastal slope south of the LYP and enhanced the rainfall there. In addition, the approaching east-west oriented rainband from southeast Taiwan also strengthened the rainfall intensity over northeastern Taiwan. Two sensitivity tests were performed to examine the effect of the orographic lifting of the moist airstream on the production of heavy rainfall. The sensitivity experiment with Taiwan's topography removed (the NT run) shows that the simulated accumulated rainfall over northeastern Taiwan was less than 50 mm in one day, much less than in the control run (CR run). In the NT run, the low-level convergence over northeastern Taiwan produced by the synoptic circulations and the simulated rainband still approaching northeastern Taiwan, are similar to the CR run. Another sensitivity experiment replacing the LYP with a plateau (the PL run) shows that the accumulated daily rainfall over the slope south of the LYP was reduced by ~250 mm compared to the CR run. The reduction of rainfall was caused by lifting relatively less moist air over the slope south of the LYP. These sensitivity tests indicate that the amount of low-level moisture and the orographic effects are equally important for the formation and maintenance of heavy rainfall over northeastern Taiwan under a favorable environment.

2025, Present Environment and Sustainable Development

An operational hail suppression program has been based in Romania since 2005. The program is designed to reduce hail damage in the most vulnerable agricultural areas (protected areas) of the country. An exploratory analysis of volume-scan, S-band and C-band radars data, using a storm cell tracking software, was conducted to calculate six radar-derived parameters associated with hail from 51 seeded storms during the summers of 2017 to 2022. All selected hailstorms had a lifetime of more than one hour, which was divided into three stages: before seeding, during seeding, and after seeding. The statistical t-test was used to test the null hypothesis of no seeding effect. Comparing values before seeding and during seeding, the data support claims that seeding causes an increase in most of the analysed parameters. These can indicate the stimulation of the development of seeded clouds, due to the so-called dynamic effect. After seeding, a decrease in the values of all the parameters analysed was observed (with decreases in average values ranging between 10% to 15%). Furthermore, a spatial analysis of hail kinetic energy shows that areas with values over 300 J/m 2 are lower in the protected areas compared to the neighbouring ones where the clouds have not been seeded.

2025, arXiv (Cornell University)

2025, European Journal of Remote Sensing

Flood monitoring systems are crucial for flood management and consequence mitigation in flood prone regions. Different remote sensing techniques are increasingly used for this purpose. However, the different approaches suffer various limitations, including cloud and weather effects (optical data), and low spatial resolution and poor colour presentation (synthetic aperture radar data). This study fuses two data types (Landsat and Sentinel-1) to overcome these limitations and produce better quality images for a prototype flood application in the Vietnam Open Data Cube (VODC). Visual and quantitative evaluation of fused image quality revealed improvement in the images compared with the original scenes. Ground-truth data was used to develop the study flood extraction algorithm and we found a good agreement between our results and SERVIR Mekong (a joint initiative by the US agency for International Development (USAID), National Aeronautics and Space Administration (NASA), Myanmar, Thailand, Cambodia, Laos and Vietnam) maps. While the algorithm is run on a personal computer (PC), it has a clear potential to be developed for application on a big data system.

2025, Journal of Applied Meteorology and Climatology

The strongest hurricanes over the North Atlantic Ocean are getting stronger, with the increase related to rising ocean temperature. Here, the authors develop a procedure for estimating future wind losses from hurricanes and apply it to Eglin Air Force Base along the northern coast of Florida. The method combines models of the statistical distributions for extreme wind speed and average sea surface temperature over the Gulf of Mexico with dynamical models for tropical cyclone wind fields and damage losses. Results show that the 1-in-100-yr hurricane from the twentieth century picked at random to occur in the year 2100 would result in wind damage that is 36% [(13%, 76%) 5 90% confidence interval] greater solely as a consequence of the projected warmer waters in the Gulf of Mexico. The method can be applied elsewhere along the coast with modeling assumptions modified for regional conditions.

2025, AIAA Aviation 2019 Forum

Very little data surrounding tornadogenesis exists, and this is due in part to the lack of tools necessary to deliver weather-sensing instruments into the severe weather phenomenon. Though current UAS are able to accurately gather weather data, they typically cannot operate in high winds or in rain. To help bridge this data gap, a custom delta wing UAS was developed to withstand both of these shortcomings. The aircraft was outfitted with an autopilot, long range RC control, and FPV systems for control over long distances. Despite utilizing a new turbojet that generates 50% more thrust at the cost of a 50% increase to fuel consumption, custom fuel tanks were designed and fabricated double the flight time of the previous system. Considerations for preventing ingested water from damaging internal avionics are explored, as operation in rain is a requirement. Aircraft performance approximations were generated using both analytical approximations and flight test data from the autopilot's flight log. An approach to generating a longitudinal aerodynamic control model is explored to estimate performance in extreme winds (75+ mph), but ultimately fails due to lack of conventional horizontal tail and the coupling of pitch and yaw controls to the turbine's exhaust speed (controlled by throttle setting). A car-based launcher system was also created for utilization in the field, reducing the required personnel's experience to execute a mission effectively. Multiple aircraft, as well as a prototype of the TIA, has launched successfully multiple times from this system, even exhibiting full auto-launching functionality. The longest recorded flight was over a ground track of 22 miles with an average airspeed of 100 knots over 16 minutes, consuming 60% of the total fuel available. The top speed achieved by the aircraft was 160 mph at 90% throttle.

2025, Pure Appl. Geophys

Lightning is one of the most beautiful and dangerous phenomena in nature. It is an interesting and undetermined area of research in which information is vaguely defined. It has excellent potential to produce severe damage to living bodies and properties. The process of lightning is generally dependent on different meteorological parameters. The main objective of this study is to apply the concept of a nonlinear autoregressive network with exogenous inputs to an artificial neural network model (NARX-ANN) and predict the afternoon lightning in the premonsoon season. For this purpose, three meteorological parameters, namely atmospheric temperature (AT), relative humidity (RH), and stability parameter (z/L), have been taken as inputs to the proposed model. The performance of the model was evaluated on pre-monsoon data with prediction accuracy of 96.14%. Furthermore, results obtained from the seven skill scores have been evaluated, where False Alarm Rate (FAR) and Miss Rate (MR) were found near to zero. The result shows that the NARX-ANN model has minimum prediction errors and can be considered a suitable method for forecasting lightning.

2025, Pure Appl. Geophys

2025, Weather and Forecasting

The NCEP Global Ensemble Forecasting System (GEFS) is examined in its ability to predict tropical cyclone and extratropical transition (ET) positions. Forecast and observed tracks are compared in Atlantic and western North Pacific basins for 2006–08, and the accuracy and consistency of the ensemble are examined out to 8 days. Accuracy is quantified by the average absolute and along- and cross-track errors of the ensemble mean. Consistency is evaluated through the use of dispersion diagrams, missing rate error, and probability within spread. Homogeneous comparisons are made with the NCEP Global Forecasting System (GFS). The average absolute track error of the GEFS mean increases linearly at a rate of 50 n mi day−1 [where 1 nautical mile (n mi) = 1.852 km] at early lead times in the Atlantic, increasing to 150 n mi day−1 at 144 h (100 n mi day−1 when excluding ET tracks). This trend is 60 n mi day−1 at early lead times in the western North Pacific, increasing to 150 n mi day−1 at long...

2025

A central issue in the study of impact of convective systems related to strong phenomena is the understanding of their complex structure and evolution. Such systems are often related to high precipitation rate, strong winds and hailfall. Satellite observations and cloud microphysical model (CMM) simulations have proven to be effective in the study of this kind of phenomena. These two approaches, even different, complement themselves in the description of convection, providing an observative approach joins with a theoretical one. A peculiar characteristic of cloud top of deep convective system has been defined as Enhanced-V or V-Shape; different studies have been performed so far to describe and explain this feature (e.g. Heymsfield et al, 1983ab). McCann (1983) accumulated V statistics from half-hourly enhanced IR data from April to July 1979. He found that storms with a V pattern had about 70% probability of producing severe weather, and that the median lead time from the onset of ...

2025, Journal of Aircraft

28 storm-penetrating aircraft during nine different research projects conducted between 1991 and 2003 are analyzed. These flights, usually flown during the summer months in the central and high plains in the United States, targeted regions of convective storms containing vigorous updrafts, downdrafts, and precipitation, including hail. Observations indicate that three of the most hazardous components of flying in summertime deep convective clouds are aircraft icing, turbulence from strong vertical wind gradients, and hail. There is also a smaller, but still important, threat from lightning. Statistics of the observations show that at any given time there is approximately a 10% probability of encountering severe icing conditions, approximately a 0.1% probability of encountering extreme turbulence, and approximately a 0.2% probability of encountering hail with mean diameter 2.5 cm or greater within convective clouds in the 4-7 km mean sea level altitude range. The purpose of this study is to analyze the convective environments under which these hazards occur in order to provide reference and/or guidance for conditions that might be encountered within summertime convective clouds by aircraft.

2025, Monthly Weather Review

This paper examines the cyclogenesis of the ''Perfect Storms'' of late October and early November 1991 over the North Atlantic and focuses on the influence of Hurricane Grace (HG) toward their development. The two storms considered are the ''Perfect Storm'' (PS) that underwent a warm seclusion process and an extratropical cyclone (EC1) with two development phases. HG, which initially formed via tropical transition (TT), influenced the first phase of EC1 via reduced atmospheric static stability and enhanced low-level baroclinicity. As a result, deep moist convection and latent heat release produced maxima in midtropospheric diabatic heating and lower-tropospheric potential vorticity (PV) that aided the development of EC1. Backward air parcel trajectories and large diabatic contributions to eddy available potential energy (APE) generation suggests that EC1 developed as a diabatic Rossby vortex (DRV)-like feature. The second and explosively deepening phase of EC1 occurred as the cyclone coupled with an uppertropospheric PV disturbance (PVD) over the eastern North Atlantic. Backward air parcel trajectories demonstrate the explosive deepening of EC1 involved airstreams originating from east of HG and from over the Labrador Sea. Parcel trajectories and a large baroclinic contribution to eddy APE generation further suggests that the two-phase development of EC1 may have involved a DRV-like feature. The subsequent recurvature and extratropical transition (ET) of HG occurred in the warm sector of the PS downstream of a second upper-tropospheric PVD over the western North Atlantic. Reduced atmospheric static stability, enhanced warm air advection, and strong latent heat release during the recurvature and ET of HG contributed to the development of a strong, zonally oriented warm front and the warm seclusion of the PS. Parcel trajectory analysis demonstrates that the PS warm seclusion involved the isolation of air parcels by a bent-back warm front that were warmed via sensible heating from the underlying Gulf Stream.

2025

This study provides insights into large fires in the Pantanal by analyzing the atmospheric conditions that influenced the rapid fire evolution between 13 and 14 November 2023, when fire fronts spread rapidly, leading to critical situations for firefighters. The observation-based analysis helped us to identify some characteristics of the fire’s evolution and the meteorological conditions in the region. Furthermore, two simulations were run with the Meso-NH model, which was configured with horizontal resolutions of 2.5 km and 5 km. The fire behavior, characterized by satellite observations, revealed periods with a sudden increase in active fire numbers. High temperatures and low relative humidity in the region characterized the fire weather conditions. The simulations confirmed the critical fire condition, showing the benefits of increasing the resolution of numerical models for the Pantanal region. The convection-resolving simulation at 2.5 km showed the repeated development of gust fronts in the late afternoon and early evening. This study highlights this dynamic that, coupled with intense surface wind gusts, was crucial for the intensification of the fire spread and unexpected behavior. This study is a first step toward better understanding fire dynamics in the Pantanal through atmospheric modeling, and it can support strategies for firefighting in the region.

2024, American Journal of Climate Change

One of the more critical issues in a changing climate is the behavior of extreme weather events, such as severe tornadic storms as seen recently in Moore and El Reno, Oklahoma. It is generally thought that such events would increase under a changing climate. How to evaluate this extreme behavior is a topic currently under much debate and investigation. One approach is to look at the behavior of large scale indicators of severe weather. The use of the generalized extreme value distribution for annual maxima is explored for a combination product of convective available potential energy and wind shear. Results from this initial study show successful modeling and high quantile prediction using extreme value methods. Predicted large scale values are consistent across different extreme value modeling frameworks, and a general increase over time in predicted values is indicated. A case study utilizing this methodology considers the large scale atmospheric indicators for the

2024

The skill of a combined grand ensemble (GE), which is constructed from three operational global ensemble prediction systems (EPS), is evaluated with respect to the probability forecast of a tropical cyclone (TC) being within a specified area. Anisotropic probability ellipses are defined from the GE to contain 68% of the ensemble members. Forecast reliability is based on whether the forecast verifying position is within the ellipse. A sharpness parameter is based on the size of the GE-based probability ellipse relative to other operational forecast probability ellipses. For the 2010 Atlantic TC season, results indicate that the GE ellipses exhibit a high degree of reliability whereas the operational probability circle tends to be over-dispersive. Additionally, the GE ellipse tends to be sharper than the operational product for forecast intervals beyond 48 hours. The size and shape of the GE ellipses varied with TC track types, which suggests that information about the physics of the flow-dependent system is retained whereas isotropic probability ellipses may not reflect variability associated with track type. It is concluded that the GE probability ellipse demonstrates utility for combined EPS to enhance probabilistic forecasts for use as TC-related decision aids, as there is a potential for reducing the sizes of warning areas.

2024, 99th American Meteorological Society Annual Meeting

2024

Two organizations within the National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service (NWS) are responsible for disseminating critical information to their customers prior to and during severe weather. The Storm Prediction Center (SPC) focuses on conducting an overall assessment of the environmental conditions on the national scale, and issues the appropriate severe weather watches. At the local level, Weather Forecast Offices (WFO) are responsible for issuing warnings to cover imminent severe weather threats. The focus of this research is primarily on the evaluation of the NWS watch and warning performance in relation to tornadic events from 1997 to 2007. Data are obtained from the NOAA Performance Management Website and the SPC watch database. The watch and warning records are matched to each tornadic event, allowing an evaluation of tornado warning performance in relation to watch type and lead time. Statistical analysis of the data reveal interesting res...

2024

The paper addresses the bioclimatic conditions of selected towns of the southern part of the Polish Baltic Coast on the basis of the UTCI index. Moreover, the authors, by using observational data from coastline stations, as well as reanalysis data of the mean sea level pressure and the 500 hPa geopotential height from the NCEP/NCAR, attempt to explain which synoptic situations are conductive to the occurrence of days with very strong and extreme cold or heat stress. The research proved that the lack of thermal stress occurs most frequently. Among days with aggravating conditions days with the cold stress category appear most frequently. The study of long-term trends showed a statistically significant increase in the value of the UTCI index in the year and seasons. An analysis of days by the UTCI index category trends showed an increase in the number of days with conditions of both heat and cold stress in Świnoujście and Łeba, heat stress in Kołobrzeg and cold stress in Hel.

2024, Journal of the Atmospheric Sciences

Several hypotheses have been put forward for the mechanisms of generation of surface circulation associated with tropical cyclones. This paper examines high-resolution simulations of Tropical Storm Gert (2005), which formed in the Gulf of Mexico during NASA’s Tropical Cloud Systems and Processes Experiment, to investigate the development of low-level circulation and its relationship to the precipitation evolution. Two simulations are examined: one that better matches available observations but underpredicts the storm’s minimum sea level pressure and a second one that somewhat overintensifies the storm but provides a set of simulations that encapsulates the overall genesis and development characteristics of the observed storm. The roles of convective and stratiform precipitation processes within the mesoscale precipitation systems that formed Gert are discussed. During 21–25 July, two episodes of convective system development occurred. In each, precipitation system evolution was char...

2024, Meteorological Applications

Surface observations, satellite and radar imagery and cloud‐to‐ground lightning data are used in an observational study of two cases that produced severe weather in Catalonia (Spain). The first one occurred on 24 August 1993; a squall line crossed Catalonia from west to east producing heavy rain with rates of up to 100 mm h−1 and hail of 7 cm diameter. The observational information provided is a good tool for monitoring the event and issuing a reasonable nowcast. The second case, which occurred on 31 August 1994, was associated with the development of a tornado (F1 in the Fujita scale) as well as hail of up to 5 cm diameter. In this case the convection was almost stationary and no clear signatures of severe weather can be identified from available satellite and radar imagery. Copyright © 1997 Royal Meteorological Society