North Carolina Advanced Air Mobility Weather Study

Prepared For:                                                                                                                                      
AeroX 
1 W 4th Street STE 740 
Winston-Salem, NC 27101 

Prepared By: 
TruWeather Solutions, Inc. 
VA/DC Headquarters, 1303 Sawbridge Way 
Reston, VA 20194 

Introduction: The report outlines the initial steps taken to evaluate and prepare urban areas in North Carolina for Advanced Air Mobility (AAM) operations. It covers a complete overview of climate conditions throughout the state, operability assessments, expert evaluation of high-impact weather patterns, analysis of the current weather sensing network, and recommendations for future steps.

Purpose: Extreme weather conditions such as high temperatures, wind shear, turbulence, thunderstorms, and moisture can significantly impact both flight operations and passenger comfort. Currently, aviation weather systems rely heavily on pilots to identify and avoid weather hazards that are not detected by existing systems. In urban environments with high-rise buildings, wind shear, and turbulence hazards can be unpredictable, creating a challenge for Uncrewed Aircraft Systems (UAS) that lack onboard pilots. As regulations for Beyond-Visual-Line-of-Sight (BVLOS) operations for UAS evolve, there is a growing need for higher-resolution microclimate information to facilitate more comprehensive flight planning, risk mitigation, and in-flight decision-making.

Scope: AeroX’s AAM Weather Study sought to identify the current limitations and gaps in the existing methods for observing the atmospheric boundary layer (ABL) and urban boundary layer (UBL), as well as show how a collaborative ground-based weather sensor network could address these limitations and gaps through 3rd Party Weather providers (3PWP).

The report included a state-wide baseline assessment of regional microclimate conditions, which identified potential hazards and limitations of low-level aerial flight. Vertiport operations were also assessed, given the weather and time-based thresholds. Finally, an in-depth weather assessment was produced, which focused on specific flight risks: wind, temperature, precipitation, clouds, and visibility.

Methodology of Analysis:

• North Carolina Climate Summary: The state was divided into three regions: Mountain, Piedmont, and Coastal Plains, based on unique micro-climate, topography, and land-use characteristics. These metrics helped determine specific hazards and limitations for low-altitude aerial flight, such as turbulence, precipitation, and fog.
• Vertiport Operability Index (VOI): The VOI measures aircraft operability as a percentage using DM-AirTech’s VertiPlace^GWC system within an operational window of 8:00 AM-6:00 PM ET. The VOI analysis was divided into four aircraft classes: Commercial Drones, Passenger Multicopters, Vectored Thrust, and Helicopters, and it outlines critical weather conditions that affect operability based on historical weather data for each of them.
• High Impact Weather Assessment: An in-depth review was conducted on weather conditions that affect Advanced Air Mobility operations within four metropolitan regions in North Carolina: Winston-Salem/Greensboro/High Point, Asheville, Charlotte, and Raleigh/Durham/Chapel Hill. The assessment is based on datasets of existent reliable weather observation systems: Automated Surface Observing System (ASOS) and Automated Weather Observing System (AWOS). Long-term climate data was accessed using the Global Historical Climatology Network (GHCN), and daily and hourly precipitation estimates were found using the National Centers for Environmental Prediction (NCEP) Stage IV Radar Data. Visibility impacts were measured using the FAA’s standardized Flight Rules (VFR, MVFR, IFR, LIFR).

Findings:

• High-Impact Weather Assessment: The weather assessment findings for North Carolina were reported for the four highlighted metropolitan regions. The report included information on wind patterns, temperature, precipitation, and visibility in each city. The urban heat island effect was found to impact high temperatures in developed areas of cities. Precipitation varied by season, with summer typically bringing the most precipitation. Low clouds and fog were common in the fall and winter months, especially near bodies of water and in valleys. The report also highlighted the need for a densified sensor system to mitigate biases in precipitation measurement.
• Findings of Gap Analysis: Observation systems such as Automated Surface Observing Systems (ASOS) and Automated Weather Observation Systems (AWOS) are reliable but limited to airport locations and only valid within 5 NM of the aerodrome center point. Other systems, such as county and local government stations and weather radar, offer higher quality control and more dense network coverage. Weather balloons and satellites provide high-altitude measurements but limited insights into low-altitude conditions. Limitations of these systems include gaps in measuring cloud ceiling height and wind speed, among other factors. In general, there is a lack of valid data between airports and limited data aloft within the boundary layer.
• Existing Conditions Survey Findings: The sensor network for the four metropolitan regions included assessing the proximity and potential accuracy of the ASOS, AWOS, Mesonet sensors, weather radar, and radiosondes. To obtain precise and up-to-date weather information, it is essential to understand the coverage, limitations, and data provided by each sensor.

Conclusion: AeroX recognizes the importance of partnerships to safely integrate AAM into communities. A diverse and densified weather observation system is required to address weather uncertainty due to insufficient weather observation networks. Legacy weather systems are assessed to supplement AAM across North Carolina, including the establishment of partnerships to deploy and sustain novel sensors. There is an opportunity to accelerate the adoption of the ASTM F38 Weather Standard, and future forecast weather standards, in the Winston-Salem area through FAA guidance and support. AeroX can facilitate weather sensor reference networks to accelerate innovation and safer flight operations.

Recommendations for Future Steps: North Carolina can partner with TruWeather to test advanced weather sensing tech and improve data capabilities, benefiting UAS operators, AeroX, NC, and the FAA. ClimaVision deployed three X-band radars in central NC to enhance severe weather tracking and provide higher-resolution insights. AeroX received $5 million to develop Project ATLAS, which establishes a Ground-Based Surveillance System for non-cooperative aircraft surveillance. AeroX plans to partner with third-party weather sensor providers and install sensors in public and private infrastructure locations to maintain UAS operations.

AeroX proposes the adoption of the ASTM F38 Weather Standard, which identifies gaps in the existing weather observation system and recommends strategic assessments and deployment of novel weather systems. Low-altitude aviation operations are hampered by a lack of accurate weather forecasts and data. Current weather observations and products are geared towards traditional air carriers, making it difficult for low-altitude operators to achieve the desired safety level and expand operations. Collaboration is needed to enhance weather data collection, modeling, forecasting, and stakeholder engagement.