Meteorology Commons^™

The Effects Of Downdraft And Radial Ventilation In Hurricanes Earl (2010) And Edouard (2014), Jacob Vile

Electronic Theses & Dissertations (2024 - present)

Tropical cyclone (TC) intensity change in moderate vertical wind shear (VWS) is difficult to predict. Specifically, ventilation, the intrusion of dry and/or cool (i.e., low equivalent potential temperature (theta-e) air inside the TC, can have differing effects on TCs. Downdraft ventilation is the downward transport of below-mean  theta-e air by downdrafts, and radial ventilation is the inward transport of below-mean theta-e air by storm-relative radial winds. If this low theta-e air is able to get ingested by updrafts, it can result in a reduction of convection in the TC, thereby reducing intensity. Although most studies of ventilation have been conducted …

Key Processes Involved In The Vortex Alignment Of Sheared Tropical Cyclones, Luis O. Hernandez

Electronic Theses & Dissertations (2024 - present)

Tropical cyclones (TCs) are challenging to forecast when under vertical wind shear (VWS). VWS tilts a TC’s vortex, creating asymmetries in its structure that impedes intensification. Although work has been done to conceptualize and understand how TCs evolve under shear and how they axisymmetrize and intensify, vortex alignment remains a complex and unresolved topic. The goal of this study is to assess what physical processes are important to tilt reduction and how these processes evolve in weak TCs. Using the Hurricane Analysis Forecast System Model-B (HAFS-B) 2.1, a case study on two storms, Hurricane Earl (2022) and Hurricane Lee (2023) …

Drivers Of Extreme Streamflow During A Snowmelt-Enhanced Heavy Rainfall And Atmospheric River Event In The Catskill Mountains Of New York, Christopher A. Gilberti

Electronic Theses & Dissertations (2024 - present)

This study uses atmospheric reanalysis, precipitation and snow water equivalent (SWE) analyses, mesonet observations, and streamflow records to examine the impact of an atmospheric river storm that produced heavy rainfall and snowpack ablation across the Catskill Mountains of New York on 24–25 December 2020. Earlier in December, an antecedent storm produced SWE values in the Catskills above the 90^th percentile for that point in the season. The atmospheric river event followed with strong southerly warm-air advection ahead of an anomalously deep trough, temperatures and dewpoints that exceeded 10°C, and heavy orographically enhanced rainfall and rapid snowmelt. Sensible heat fluxes …

The Impact Of Downdraft Ventilation On Tropical Cyclone Intensity And Structure Using Aerial Reconnaissance Observations, Nicholas E. Johnson

Electronic Theses & Dissertations (2024 - present)

Tropical cyclone (TC) intensity can be challenging to predict since it is modulated by many physical processes. One of these processes is ventilation: the injection of relatively cool, dry environmental air into the warm core of a TC that acts as “anti-fuel”, inhibiting intensification and increasing uncertainty with intensity forecasts. While ventilation has been examined in numerical modeling studies, there have been a limited number of observational studies investigating ventilation. The two primary objectives of this dissertation are to develop methods for measuring downdraft ventilation from aerial reconnaissance observations and to use those observations to better understand how ventilation affects …

2025 - Tennessee Climate Snapshot, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Monthly Reports

No abstract provided.

2025 - Tennessee Annual Climate Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Monthly Reports

Excerpt: 

The mean (average) temperature for 2025 across Tennessee was a bit warmer than normal for most of the state, with the majority of areas reporting temperatures that were 1-2°F above the 1991-2020 NOAA climate normals, with some areas, mostly in the northeastern section of the state within one degree of normal. However, there were a lot of temperature swings throughout the year with below normal temperatures for most regions of the state in January, July, August, and November, while well above normal temperatures were observed in parts of the state in February, April, May, and June [...]

Smart Pireps: Leveraging Technology To Simplify Pilot Weather Reporting In General Aviation, Emma Hellwege

Honors Projects

This honors project examines how emerging aviation technologies can support or automate components of Pilot Weather Reports (PIREPs) to improve reporting accuracy, reduce pilot workload, and increase participation within the general aviation (GA) community. PIREPs provide essential real-time weather observations—such as turbulence, icing, and visibility—that supplement automated systems and enhance situational awareness for pilots, air traffic control, and meteorologists. However, reports are vastly underutilized due to workload constraints, inconsistent training, voice-only submission methods, and technological disparities across the GA fleet.

Through a structured analysis of federal aviation documentation, sensor capabilities, human factors research, and recent advancements in automation, this study …

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

Tennessee Climate Office Monthly Reports

Hi All,

December was defined by quite a bit of temperature variability (though the temperature swings resulted in near-normal monthly averages) and an overall dry pattern.

The month started out cooler than normal, with a slight moderation in the second week of the month, before a strong cold front sent temperatures tumbling into the teens or single-digits and wind chills into the single digits or below zero on December 14 and 15 - with many locations stuck in the 20’s or even teens for high temperatures. Following this cold weather, temperatures quickly rebounded into the normal and then well above …

Dynamics, Predictability And Impacts Of Multi-Year La Niña Event, Nahid A. Hasan

All Graduate Theses and Dissertations, Fall 2023 to Present

This dissertation investigates the dynamics, predictability, and impacts of multi-year La Niña events. Multi-year La Niña events are referred to as extended periods of unusually cooler tropical Pacific that persist for two or more consecutive winters. These prolonged events can increase the risk of natural hazards such as droughts, floods, and heatwaves in the western US and around the world. Despite their worldwide significance, questions remain about the mechanisms driving their initiation, their predictability, and regional hydroclimate impacts.

The first chapter of the dissertation introduces what scientists currently believe causes them, and how well different types of climate models can …

An Objective Method To Locate Shear Lines During The Northeast Monsoon Season In The Philippines, Lyndon Mark P. Olaguera, John A. Manalo, Jun Matsumoto, Faye Abigail T. Cruz, Jose Ramon T. Villarin

SOSE Affiliate: Manila Observatory

The shear line is a narrow zone of maximum horizontal wind shear, typically identified as a confluence zone of low-level wind streams. Previous studies showed that this system can trigger heavy to extreme rainfall events in the Philippines during the northeast monsoon season. However, a research gap remains in objectively identifying and locating this system. Thus, this study develops a detection method that may be used for monitoring and forecasting the location of shear lines. Results show that the gradient of meridional winds in the y-direction (∂V925hPa/∂y), the boundary layer moisture flux convergence, and the 925 hPa relative vorticity may …

Climatology Of Northeast Winds In Northern And Central California: A New Characterization Of The Diablo Wind, Alana R. Macken

Master's Theses

Diablo winds in northern California are known for driving some of the most destructive wildfires in state history. The Camp Fire of 2018, which caused at least 85 civilian fatalities, is just one example of the devastating outcomes associated with these rapidly developing downslope windstorms. While they are known to occur most frequently from fall through spring, much about the structure, evolution, and full spatial extent of these events remains poorly understood. Most previous studies have focused on a limited number of high-impact cases or have defined events using humidity-based thresholds in isolated regions such as the North Bay. As …

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

Tennessee Climate Office Monthly Reports

Hi All,

The month of November 2025 averaged warmer than normal by 2-4°F across most of the state. The northeastern corner of TN was closer to average, with a few areas even slightly cooler than normal. Additionally, November was drier than normal for most areas, with the exception of a few parts of the Cumberland Plateau and in East TN where heavier bands of precipitation set up while most of the state recorded only light rainfall.

The main weather and climate story of November 2025 was the early taste of winter that impacted the state November 9-12, which also coincided …

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

Tennessee Climate Office Monthly Reports

Hi All,

October 2025 was a quiet month for weather across Tennessee. The major stories included improving drought conditions across the western half of the state and relatively large temperature fluctuations. There were some days with heavy rainfall in West Tennessee but flooding was minimal due to the dry conditions in September. Tennessee experienced some pronounced temperature swings during the month with many areas reaching into the 80’s or even 90’s in the first week of October as well as in the middle of October, and then down into the 20’s or 30’s by the end of the month. This …

Synoptic-Scale Meteorological Patterns Associated With Extreme Precipitation Over The Contiguous United States And Concomitant Seasonal And Regional Variability, Amy M. Johnson

Dissertations and Theses

Seasonal and spatial variations of synoptic-scale weather patterns concurrent to extreme precipitation days, defined as days above the seasonal 95th percentile of the daily precipitation distribution, are characterized over a 44-year period (1980-2023) for the Contiguous United States (CONUS). Using atmospheric reanalysis data and a grid-cell centered approach, we construct seasonal anomaly composite patterns for sea level-pressure (SLP), integrated water vapor transport, 500 hPa geopotential height (Z500), and 300 hPa wind speed. Atmospheric variables known to be important for extreme precipitation. By interpolating composites for each grid cell onto the same polar coordinate grid relative to the grid cell we …

Stream Temperature Responses To Summer Urban Rain Events Along The Savannah River, Joseph E. Wermter, Vivian L. Turner, Max K. Appelbaum, James M. Shepherd, Jacob Z. Lott

Journal of South Carolina Water Resources

The hydrological urban heat island (HUHI) is a recent facet of the urban heat island (UHI), describing thermal enhancement of bodies of water in response to urbanization. Although the forefront of this work has been studied for large Metropolitan areas, this effect on developing cities is currently unknown. To locally measure and quantify HUHI effects in a developing city, we utilized Multi-Radar Multi Sensor (MRMS) radar-derived rainfall data to estimate rainfall in the Augusta Metropolitan Area (AMA) and the Savannah Metropolitan Area (SMA), two developing communities adjacent to the Savannah River. We analyzed mean temperature trends of two stream gauges …

Multimodel And Multidiagnostic Ensemble-Based Deep Convective Area Forecast For Aviation Operations Using The Global Unified Model And Korean Integrated Model, Yi-June Park, Jung-Hoon Kim, Dan-Bi Lee, Hyun-Joo Choi, Soo-Hyun Kim, Matthias Steiner, Seung Hee Kim

Institute for ECHO Articles and Research

To provide safe and efficient guidance for aircraft operation to avoid deep convective areas (DCAs) in Korea and broader East Asia, we developed a multimodel and multidiagnostic ensemble (MMDE)-based forecast system. This system utilizes two global numerical weather prediction (NWP) models based on the Unified Model (UM) and the Korean Integrated Model (KIM) operated by the Korea Meteorological Administration. To predict hazardous weather conditions, we defined DCAs using ground-based radar mosaic data where the 15-dBZ echo-top height exceeds flight level (FL) 250 (about z = 6.5 km) and FL350 (about z = 9 km). For predictors, we employed a …

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

Tennessee Climate Office Monthly Reports

Hi All,

The main weather and climate stories of September 2025 for Tennessee were the hot and dry conditions in West Tennessee that led to rapid drought expansion. While the month started out cool, warmer than normal conditions built back into the state from west to east in the second and third weeks of September. Daytime temperatures were especially high, with many locations in the western half of the state seeing high temperatures that were 5-15°F warmer than normal for this time of the year. This combined with a lack of rainfall over the summer season led to rapid drought …

Understanding How Nws Meteorologists Tailor Hazardous Weather Messaging To Core Partners And Identify Local Vulnerabilities, Allison Camille Harvey

Theses and Dissertations

Over the past few decades, the National Weather Service (NWS) has continued to improve impact-based decision support services (IDSS) efforts to strengthen communication with core partners. This study addressed how a new spatially hazard-specific vulnerability tool called the Brief Vulnerability Overview Tool (BVOT) may impact how NWS meteorologists tailor messaging to their core partners. It was found that relationship building between NWS meteorologists and core partners is key to enhancing trust, especially during blue sky days. This was done by learning core partners’ needs, thresholds, and communication styles when presenting weather information. Core partners also noticed cues from NWS meteorologists …

Exploring The Use Of A Random Forest In Correcting Gfs Tropical Cyclone Landfall Errors, Victoria Grace Maxwell

Theses and Dissertations

While Tropical Cyclone (TC) track forecasting has improved over the years it has been slow. These improvements can be attributed to increased computer capability and better model inputs. Machine learning has been used for forecasting different TC track and intensity. The study here looks to use a Random Forest to predict the TC latitude/longitude “landfall” at 72-hr and quantify improvements to the GFS forecast. Principal Component Analysis was used to reduce the dimensionality of the meteorological variables. Stepwise regression was used to determine the principal components that were important for forecasting landfall. These variables were then tested with a multivariate …

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

Tennessee Climate Office Monthly Reports

No abstract provided.