Meteorology Commons^™

2025 August - Tennessee Monthly Climate Report, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Monthly Reports

No abstract provided.

Low-Level Polarimetric Signatures Of Supercells During Ef3+ Tornado Production, Anthony Noah Began

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Most EF3+ tornadoes are produced by supercells. Understanding of microscale features surrounding intense tornado production remains limited. This research aims to determine commonalities in low-level microphysical processes during intense tornado production via polarimetric radar signature assessment with a Python-based algorithm. Polarimetric variables hypothesized to reflect low-level wind profiles such as the differential reflectivity (Z_DR) arc and the Z_DR–K_DP (specific differential phase) separation vector will be investigated. Supercells which produced EF3+ tornadoes will be examined since these tornadoes pose the highest threat. From 2010 to 2024, the United States recorded approximately 19,100 tornadoes which resulted in …

Environmental Controls Of Hail In Quasi-Linear Convective Systems, Cameron A. Barker

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

A study of hail occurrence in quasi-linear convective systems (QLCS), as well as severe weather parameters contributing to the likelihood and intensity of hail, is presented. Rapid Refresh (RAP) proximity soundings for 218 QLCS events from 2012 to 2022 are selected to sample QLCS environments near peak intensity. Study objectives are to assess common environmental parameter spaces that favor hail in QLCSs while connecting these findings to results for supercells. Hail occurrence is also examined in terms of synoptic regime.

Six synoptic regimes were identified to support QLCSs with hail, from high shear, low cape (HSLC) to low shear, high …

Adaptive Crop Switching For Irrigated Agriculture In Response To Climate Change In The Western U.S., Shahryar Fazli, Wenzhao Li, Surendra Maharjan, Rejoice Thomas, Aqil Tariq, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Adaptive irrigation strategies are crucial for balancing water use, economic viability, and food security in the arid Western United States. However, as a key indicator vital in regulating agricultural productivity and crop irrigation, water use efficiency (WUEc) is becoming increasingly complex to estimate due to climate change. This study explores the critical role of key meteorological drivers, such as maximum temperature (tmax) and vapor pressure deficit (vpd), and their impacts on crop-specific WUEc. Future impacts are also assessed through integrating machine learning models with climate projections from the CMIP6 framework under SSP2–4.5 and SSP5–8.5 scenarios to forecast WUEc trends from …

Evaluation Of Windninja Simulations In Canyons And Complex Terrain, Marc Buchs

Master's Theses

This study describes a validation of the surface wind model WindNinja conducted over different types of complex terrain. WindNinja is one of many software tools first responders use to better understand wind flow over such terrain. One approach to receive a higher resolution wind field to account for local terrain effects is to downscale numerical weather prediction model output with the help of WindNinja. 2 km resolution Weather Research and Forecasting model (WRF) output was used as input for our WindNinja simulations. We tested the surface wind model for two case sites in California characterized by canyons of different terrain …

Interactions Between A High Intensity Wildfire And An Atmopsheric Hydraulic Jump In The Case Of The 2023 Lahaina Fire, Clifford Dw Ehrke

Master's Theses

On 8 August 2023, a grass fire that started in the city of Lahaina, Hawai’i, grew into the deadliest wildfire in the United States since 1918. This wildfire offers a unique opportunity to explore the impact of high heat output on an atmospheric hydraulic jump and a downslope wind event. We conducted two WRF-SFIRE simulations to investigate these effects: one incorporating fire–atmosphere feedback and the other without it. We compare these WRF-SFIRE simulations to all available data regarding the fire event, including high resolution satellite data, weather station data from other parts of Maui and the Hawaiian Archipelago, and official …

2025 July - Tennessee Monthly Climate Report, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Monthly Reports

Hi All,

The main story for July was the high heat and humidity that spread across the state for the second half of the month. Most counties in the state saw at least 1 day with a heat advisory or extreme heat warning issued by the National Weather Service due to a combination of high temperatures and humidity that sent heat index values above advisory/warning criteria. The western half of the state saw higher heat index values and were impacted by the heat wave for a longer period of time than the eastern half of the state. Some part of …

A Uas-Centered Investigation Of Vorticity Characteristics And Cold Pool Structure Across Forward And Left-Flank Boundaries In Supercells, Mark R. De Bruin

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Supercell internal boundaries are the locus of tornadogenesis; thus, understanding the characteristics of these boundaries, particularly in terms of vorticity, is important for identifying the role they play in tornado formation. Insight into the overall characteristics of internal boundaries and their possible role in tornadogenesis have been driven by studies reliant on numerical modeling-based experiments. Observational studies often neglect above-surface conditions or, when these observations are made, lack the spatial resolution to resolve boundary characteristics. During TORUS (Targeted Observation by Radars and UAS of Supercells) 2019 and TORUS-LItE (TORUS Left-flank Intensive Experiment) 2023, uncrewed aircraft systems (UAS) and mobile mesonets …

Influence Of Tropical Cyclones, Southwest Monsoon, And Tropical Cyclone-Enhanced Southwest Monsoon On Rainfall Variability Over The Western Coast Of The Philippines, Alwin Bathan, Lyndon Mark Olaguera, Faye Abigail T. Cruz, Jose Ramon T. Villarin, Joel T. Maquiling, Maria Obiminda L. Cambaliza, John A. Manalo, Jun Matsumoto

SOSE Affiliate: Manila Observatory

This study investigates the processes driving interannual variability of rainfall over the western coast of the Philippines during the peak southwest monsoon (SWM) months (July–September) from 1961 to 2022. Specifically, it describes how tropical cyclones (TC), SWM, and TC-enhanced SWM influence SWM rainfall variability. Rainfall measurements from 11 stations along the western coast of the Philippines were classified into three types: direct TC rainfall (PD), indirect TC rainfall (PI), and SWM rainfall (PSM). The yearly contributions of PD, PI, and PSM to SWM rainfall were estimated to be 15.4 %, 33.1 %, and 51.5 %, respectively. Furthermore, four rainfall variability …

2025 June - Tennessee Monthly Climate Report, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Monthly Reports

Hi All,

The main story of June 2025 was the first major heat wave of the year that sent temperatures into the mid-to-upper 90’s and heat index values over 100°F for most locations in the state from June 22nd to 28th. This included the first day of the year with a high over 90°F for many parts of the state. The National Weather Service offices covering Tennessee issued heat advisories for most counties in the state for at least 1 day during this period and several areas of West and Middle Tennessee had multiple days in a row with these …

Simulations Of Differential Reflectivity Columns In Quasi-Linear Convective Systems, Devon Jacob Healey

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Much research over the past decade has revealed that dual-polarization radar is a powerful tool in furthering our understanding of severe storm dynamics and subsequently improving warning strategies for these hazardous events. However, there are currently very few studies examining a particularly prolific severe convective storm mode with dual-polarization radar: quasi-linear convective systems (QLCSs). These storms can occur in any season of the year throughout most of the contiguous United States and can have immense societal impacts. Warning for the hazards produced by QLCSs is currently a significant operational challenge, therefore, research is needed to see if applying dual-polarization radar …

Investigating The Role Of Aerosols In Extreme Precipitation Events Along The Gulf Coast Of The U.S.A., Wenjia Cao

LSU Doctoral Dissertations

Atmospheric aerosols have been found to influence tropical cyclone (TC) and flood event development. In this study, the Weather Research and Forecasting model is applied to investigate specific microphysical impacts and aerosol sensitivity to heavy precipitation and TC events in the U.S. Gulf Coastal area. The Thompson aerosol-aware scheme with regular and adjusted aerosol concentration scenarios is used to quantify precipitation, wind field, horizontal/vertical structures, and track variations, by aerosol mixing ratio. In general, results for the three storms analyzed (the 2016 Baton Rouge, Louisiana, flood event (Chapter 2); Hurricane Harvey in 2017 (Chapter 3); and an idealized storm event …

Estimating The Future Frequency Of Bonnet Carré Spillway Openings, Kayla Thomas

LSU Master's Theses

In the 2010s, the Bonnet Carré Spillway (BCS) in southeastern Louisiana, U.S.A., experienced an unprecedented uptick in openings to mitigate the possibility of flooding, including a record double-opening in 2019. Both the environmental consequences of BCS openings associated with nutrients that run from the Mississippi River into Lake Pontchartrain and the synoptic-scale meteorological conditions that necessitate these openings are poorly understood. With the unexpectedly frequent openings in recent years and the ever-present threat of climate change, it is vital to consider the future shift of synoptic-scale climate patterns and how it can relate to BCS openings. Understanding the potential for …

Integrating Case Studies With Meteorologists’ Insight: Assessing Meteorologists’ Perception And Utilization Of Composite Indices, Brianna Marie Salazar

Theses and Dissertations

Meteorologists from sectors, including broadcast, academia, and operations, use derived composite indices such as 0-1km and 0-3km energy helicity index (EHI), effective-layer supercell composite parameter (SCP), fixed-layer and effective layer significant tornado parameter (STP), in addition to other resources, when developing severe local storm forecasts. This study utilizes the Weather Research and Forecasting (WRF) model to create simulations of composite indices for two tornado-producing events: 31 March 2023 and 3 May 1999. With modifications to geographical location, these simulated scenarios are then utilized in the survey to gauge how meteorologists assess where tornado potential is highest. Additionally, a combination of …

The Role Of Enso Diversity In Modulating Tornadic Activity In The United States, Davis Boyd Newton

Theses and Dissertations

Tornado activity in the United States is influenced by large-scale climate patterns, especially by the El Niño-Southern Oscillation (ENSO). While prior research has explored ENSO’s impact on severe weather, the influence of ENSO flavors, Central Pacific (CP) and Eastern Pacific (EP), on tornadic activity remains understudied. Using tornado records, reanalysis data, and sea surface temperature anomalies, we assess how convective available potential energy (CAPE), wind shear, and jet stream dynamics influence tornado frequency and distribution. Results indicate that CP La Niña years had significant increases in tornado frequency, particularly across the Midwest, Central Plains, and Southeast. EP ENSO years had …

An Investigation Into The Inclusivity, Methodology, And Education Of Severe Weather In K-12 Schools, Stephen Holden Wooten

Theses and Dissertations

Schools are a focal point in the lives of everyone in the community, especially teachers, parents, and students. Investigating the connection between these individuals and tornadoes by identifying shortcomings in education, training, and emergency procedures can induce more effective and informed decision-making for future encounters. This study evaluated the inclusivity of tornado protocols for students with disabilities, uncovered where parents prefer their child to shelter in early dismissal situations and clarified how extensively natural hazard education and tornado drills are covered in schools. Two surveys and semi-structured interviews were used to obtain responses from earth science teachers, K-12 guardians, and …

Influence Of Horizontal Grid Spacing On Numerical Weather Prediction Simulations Of Clear Air Turbulence, Kailah Rose Gordon

Theses and Dissertations

The focus of this research was to analyze the influence of horizontal grid spacing on numerical simulations of kinetic and thermal forced clear air turbulence (CAT) by quantifying uncertainty using a resolution ensemble. Previous studies indicated that microscale (< 1km) spatial resolutions are necessary to resolve turbulent kinetic energy (TKE) with low uncertainty. Six case studies of moderate or greater CAT, from pilot reports, were simulated at six horizontal grid spacings including 1, 2, 4, 8, 16, and 32km using the Weather Research and Forecast (WRF) Model. Results showed that grid spacing does influence the magnitude of uncertainty; however, the relationship between the grid spacings varied with the type of CAT being simulated and the addition of the cumulus parameterization scheme for grid spacings greater than 4km. Overall, higher precision was found between convective resolutions (1-4km), indicating that microscale resolutions are not necessary to precisely simulate TKE for CAT forecasts.

Atmospheric Turbulence Education Effects On Flight Anxiety, Megan A. Hanna

Theses and Dissertations

This study examines the effect of turbulence education on flight anxiety. A pre-post methodology measured students’ anxiety levels before and after a study abroad flight, using an educational video during the pre-flight survey to change their feelings. The Flight Anxiety Situations (FAS) questionnaire assessed anxiety at three survey points: pre-video, post-video, and post-flight. Qualitative analysis using Friedman’s test and the Wilcoxon Signed-rank test, indicated that turbulence education effectively decreased generalized and anticipatory flight anxiety, particularly in non-phobic students. Text analysis of open-ended responses suggested increased scientific knowledge post-video helped students apply technical atmospheric processes to their feelings. Turbulence education was …

Evaluating Rainfall Sensitivity Over Land To Tropical Cyclone Parameters Using Idealized Wrf, Madison C. Yawn

Theses and Dissertations

Tropical cyclones (TCs) are extreme weather events impacting the United States nearly every year. These events often cause severe damage due to the associated responses they produce including storm surge and rainfall, and the accurate estimation of these TC hazards is necessary to support coastal engineering, risk assessment, and emergency management activities. Evaluating TC-driven hazards is often done in combination with numerical models to simulate how environmental interactions alter the physical processes and responses of these storms. The purpose of this study was to simulate synthetic TC events using the Advanced Weather Research and Forecasting (WRF) model to understand how …

Real-Time Enhanced Tornado Warning Product Guidance Based On Tornado Debris Signature Height And Population Density, Alexander Cooke

Theses and Dissertations

This research aims to develop an operational program for enhancing real-time tornado warning capabilities by integrating tornado debris signature (TDS) analysis with population impact assessment. The proposed Python-based tool will ingest Level II radar data to identify and analyze TDS, estimating tornado intensity based on maximum TDS height. For high-intensity tornadoes, the program will project the potential impact area using storm motion vectors and integrate this with population density data. The system will assess whether the situation meets National Weather Service criteria for enhanced warning products, providing forecasters with rapid, objective guidance for critical warning decisions. The program’s performance will …