This page addresses meteorological analysis in New Mexico litigation involving flash flooding, wildfire conditions, sun glare, and slip-and-fall weather scenarios. For general expert witness services see expert witness services.

State-Specific Meteorology in New Mexico

New Mexico weather varies significantly due to elevation changes, mountainous terrain, and seasonal monsoon influences. Weather conditions at a specific site may differ from nearby observation stations due to localized atmospheric processes.

New Mexico’s Observation Network

Understanding which instruments recorded data near an incident site is the first step in any forensic analysis. New Mexico is served by the following government-maintained networks, each with distinct strengths and limitations for litigation use:

Source: NOAA NCEI Integrated Surface Database station list; FAA ASOS program. Elevations from NCEI station metadata. Accessed 2026-04-28.

Each of these stations archives continuous METAR observations in UTC through NOAA’s Climate Data Online (CDO) portal. Data records date to ASOS network deployment, generally 1996 forward for most sites. One-minute wind data is available at select stations where 1-min ASOS archives have been preserved by NCEI.

In addition to ASOS, New Mexico has approximately 41 Remote Automated Weather Stations (RAWS) operated primarily for fire weather monitoring. RAWS data is archived through the USDA Forest Service FAMWEB portal and provides wind, temperature, and relative humidity records in areas distant from ASOS sites. RAWS stations are particularly relevant in wildfire litigation and in rural areas where ASOS coverage is sparse.

Hazard-Specific Meteorological Considerations

Data Sources

• NEXRAD radar (with limitations)
• ASOS/AWOS surface stations
• RAWS observations
• NOAA/NCEI archives

Data Source Hierarchy and Court Acceptance

Not all weather data carries equal weight in litigation. The following hierarchy reflects the sources most consistently accepted by courts and most resistant to Daubert challenge, in descending order of evidentiary strength:

1. NOAA/NCEI archived ASOS/AWOS METAR records: Government-operated, calibrated instruments with permanent archives, UTC timestamps, and public retrieval through Climate Data Online. These records form the strongest basis for temperature, wind, and precipitation observations.
2. NEXRAD WSR-88D Level II radar data: Archived by NCEI; provides spatial coverage between stations. Confidence depends on range, beam height, and dual-polarization product availability. Radar estimates precipitation at the surface; it does not directly measure it.
3. RAWS (FAMWEB / NCEI): Archived and particularly valuable in rural and fire-prone areas. Siting standards differ from ASOS, so instrument maintenance records should be reviewed.
4. SPC Storm Reports: NWS-verified hail, wind, and tornado observations useful for corroboration and geographic bounding of severe events.
5. Numerical reanalysis grids (ERA5, CFSR): Gridded model output appropriate for corroboration and gap-filling but not for use as primary evidence where station observations exist.
6. COOP and CoCoRaHS observers (supplementary only): These networks provide daily precipitation totals and useful storm context, but CoCoRaHS is a volunteer citizen science network that lacks the calibration standards, quality control documentation, and authentication chain of government ASOS records. CoCoRaHS and COOP data should be used only to corroborate primary sources, never as standalone primary evidence. Relying on CoCoRaHS as a primary source creates a Daubert vulnerability that opposing counsel will exploit.

A forensic meteorology report that relies on multiple independent sources, for example ASOS temperature plus NEXRAD precipitation plus RAWS wind, produces conclusions that are more defensible under Daubert’s reliability prong than a report relying on a single data type.

Radar Limitations

Radar estimates are indirect and may be affected by beam height, terrain blockage, and distance from radar.

In New Mexico’s complex terrain, NEXRAD radar is primarily limited by two mechanisms: beam blockage and beam overshoot. Both cause precipitation to be underestimated or to go undetected altogether. They do not cause overestimation. Beam blockage occurs when mountain ranges obstruct the radar scan in specific azimuth sectors, preventing the radar from detecting precipitation behind the barrier. Beam overshoot occurs when the radar beam, which rises with distance from the antenna, scans over the precipitation-producing portion of a low-topped convective storm, particularly at ranges beyond 50 to 80 miles. In New Mexico, the mountain systems most likely to cause beam blockage from KABQ include the Sandia, Jemez, Sangre de Cristo, Sacramento, and Black Range systems.

This underestimation bias is critical for flash flood litigation. Radar data may show little or no precipitation at the incident location even where significant rainfall actually occurred. The expert must document the beam height above ground level at the incident location, note any known blockage sectors, quantify the likely precipitation underestimate, and assign an appropriate confidence level. These limitations do not make radar data inadmissible, but they must be disclosed and addressed.

Microclimate Effects

Elevation, terrain, and localized storm activity create significant variability in weather conditions across short distances.

New Mexico’s elevational range, from approximately 2,800 feet in the Chihuahuan Desert lowlands to over 13,000 feet in the Sangre de Cristo peaks, produces temperature differences that can exceed 15 to 20 degrees Fahrenheit over horizontal distances of only a few miles. This variability is well documented in the meteorological literature. For litigation purposes, a forensic meteorologist must evaluate not just the nearest ASOS station reading but whether the station’s elevation, aspect, and local land use are representative of the incident site. Where they are not, the expert must state the degree of uncertainty and explain the methodology used to bridge the gap.

Why This Methodology Survives Daubert

Federal courts apply the Daubert standard under Federal Rule of Evidence 702, which requires expert testimony to be based on sufficient facts or data, to employ reliable and testable methods, and to be reliably applied to the facts of the case. Under Daubert, the trial judge acts as gatekeeper and evaluates four factors: (1) whether the method has been or can be tested, (2) whether it has been subject to peer review and publication, (3) whether it has a known or knowable error rate, and (4) whether it is generally accepted in the relevant scientific community. General acceptance alone is not sufficient under Daubert; it is only one factor. General acceptance as the sole test is the older Frye standard, which some state courts still apply. Attorneys practicing in federal court should confirm which standard governs before retaining an expert.

The six-step methodology above satisfies the Daubert framework because each step corresponds to a testable, peer-accepted scientific practice:

• Defining location and time window anchors the analysis to the specific facts at issue and avoids the general-area weather summaries that courts have excluded.
• Identifying the weather regime places the event in synoptic context and establishes whether the available data plausibly captures the conditions.
• Analyzing surface observations involves retrieving government-archived METAR records with documented quality-control flags, a procedure courts regularly accept as reliable.
• Interpreting radar data with limitations is the explicit disclosure that distinguishes a forensic report from a weather printout. The expert documents what the radar can and cannot show.
• Comparing to climatological data provides statistical context for whether conditions were unusual or foreseeable.
• Stating uncertainty clearly satisfies the scientific integrity requirement and positions the report to withstand cross-examination on error rates and confidence.

Cross-Examination Considerations

• Distance from observation stations
• Radar limitations
• Localized variability

Opposing counsel in New Mexico weather cases frequently raise three additional challenges at deposition. Attorneys should be prepared to address them:

• Station representativeness: The expert should document the distance and elevation difference between the ASOS station and the incident site and explain, with reference to published instrument accuracy specifications, what uncertainty that distance introduces. Within approximately 10 miles of an ASOS station in relatively flat terrain, temperature accuracy is typically plus or minus 2 degrees Fahrenheit and wind speed accuracy is plus or minus 5 mph. These ranges widen in complex terrain and with greater station distance.
• Monsoon spatial variability: Convective precipitation during the monsoon season is highly localized. An expert who uses only a single station observation to conclude that no precipitation occurred at an incident site may be vulnerable if radar or a nearby COOP observer documented precipitation within the same time window. A defensible analysis reviews all available data sources and addresses discrepancies among them explicitly.
• Model reliance: Numerical reanalysis products such as ERA5 or CFSR are legitimate scientific tools for gap-filling, but courts and opposing experts will challenge an opinion that relies primarily on model output rather than direct observations. The expert should clearly state whether any value in the report is observed or modeled and explain why model data was necessary where station observations were unavailable.

Scope Boundary

This analysis addresses meteorology only. It does not include legal conclusions, engineering analysis, or hydrologic modeling.

Frequently Asked Questions