Radar sees the storm; people confirm it. This page covers the observation network behind every warning: SKYWARN spotters, storm chasers, METARs and aviation products, satellite imagery, and the report pipeline that turns a spotter’s call into an LSR. XWD has trained spotters among its members, and spotter reports flow through the Discord during coverage.
SKYWARN is the NWS's official volunteer storm spotter training and reporting program. Trained SKYWARN spotters provide ground-truth reports — tornado confirmations, hail measurements, wind damage — that fill the gaps radar can't see, particularly in complex terrain. XWD's spotter community operates alongside SKYWARN principles.
A storm spotter is a trained volunteer who provides real-time ground-truth observations to the NWS during severe weather events. SKYWARN-trained spotters report confirmed tornadoes, measured hail, wind damage, and flooding — directly informing warning decisions. Spotter reports of a confirmed tornado are one of the strongest inputs for upgrading a warning.
A storm chaser is someone who actively pursues severe thunderstorms, usually for spotting, photography, research, or media. Most chasers work alone or in small teams and rely on a mix of radar apps, forecasts, and visual cues to position safely near tornadoes. The line between chasers (who position near storms) and spotters (who stay in their community and report) is mostly about mobility.
A mesonet is a dense network of automated weather stations covering a region — usually a state — at much finer spacing than the standard ASOS network. The Oklahoma Mesonet (120+ stations) and West Texas Mesonet are gold-standard examples. Mesonets give forecasters real-time, ground-truth observations of mesoscale features like outflow boundaries and dryline positions.
CoCoRaHS (Community Collaborative Rain, Hail and Snow Network) is a volunteer-based rainfall and snowfall observation network with 20,000+ active observers across North America. Daily precipitation reports feed directly into NWS datasets, filling in the significant gaps between official weather stations. Arguably the most impactful citizen science program in U.S. weather.
A surface analysis is a map showing current surface weather features — fronts, low/high pressure centers, dew points, winds, isobars — created by the WPC every 3 hours. It's the fundamental "state of the atmosphere right now" map for synoptic pattern recognition. Essential context for any severe weather or precipitation event.
A METAR (Meteorological Aerodrome Report) is a standardized surface weather observation from an airport, issued hourly (or when conditions change significantly — SPECI). It encodes wind, visibility, sky condition, temperature, dewpoint, altimeter setting, and present weather. METARs are the backbone of surface analysis.
A TAF (Terminal Aerodrome Forecast) is a 24–30 hour aviation weather forecast for conditions within 5 miles of an airport. Issued every 6 hours by the NWS. TAFs cover wind, visibility, sky condition, and significant weather. Flight operations (instrument vs. visual) depend heavily on TAF accuracy.
A SIGMET (Significant Meteorological Information) is an aviation weather advisory covering hazardous conditions affecting all aircraft: severe or extreme turbulence, severe icing, widespread dust/sand storms, volcanic ash, and tropical cyclones. Convective SIGMETs specifically target areas of hazardous convection above FL250 (25,000 ft).
A PIREP (Pilot Report) is a real-time weather observation made by pilots in flight, submitted to ATC or flight service. PIREPs report turbulence, icing, cloud tops, and visibility. They are the primary source of upper-air weather information between radiosonde launches and are critical for NWS forecasters during active weather.
GOES (Geostationary Operational Environmental Satellites) are NOAA's primary weather satellites. GOES-East (GOES-16) covers the eastern U.S. and Atlantic; GOES-West (GOES-18) covers the western U.S. and Pacific. The ABI (Advanced Baseline Imager) on GOES-R series produces 16-band imagery every 30 seconds during rapid-scan mode.
Visible satellite imagery detects reflected sunlight. It shows the finest cloud detail (cloud tops, texture, shadows) but only works during daytime. Meteorologists use it to identify cloud thickness, convective initiation, storm organization, and boundaries. The enhanced IR channel provides color-coded cloud-top temperature data at night.
Infrared (IR) satellite imagery detects heat emitted by cloud tops (or the surface). Colder cloud tops appear bright white (indicating tall, deep clouds); warmer surfaces appear darker. Enhanced IR applies a color scale — purple and black indicate extremely cold tops associated with intense convection and possible severe weather.
Water vapor imagery detects moisture in the middle to upper troposphere (roughly 300–600 mb). Bright areas = moist; dark areas = dry. Even cloudless regions show moisture patterns. Meteorologists use water vapor loops to track jet stream position, upper-level divergence, dry slots, and moisture surges days before they arrive at the surface.
The Geostationary Lightning Mapper (GLM) on GOES-16/18 detects total lightning (cloud-to-ground and in-cloud) across the Americas at 2 km resolution. Lightning jump algorithms (rapid increases in flash rate) are some of the best 0–10 minute predictors of a storm becoming severe or tornadic.