About Airmass Wx

Airmass Wx is a soaring forecast and aviation weather map for pilots in North America, Europe, South America, southern Africa, New Zealand and Australia. It turns the HRRR, GFS, ECMWF, ICON and ICON-D2 weather models into the numbers pilots fly by: how strong the thermals are and how high they go, where the cloudbase is, how far you can fly cross-country, where the ridges work and where the wave sets up. General aviation pilots get flight rules, ceilings, visibility, winds aloft, icing and turbulence on the same map.

Who makes Airmass Wx

I'm Eitan Steinberg. I build and run Airmass Wx myself. I'm a glider pilot with the Brandywine Soaring Association and a member of the Soaring Society of America.

I started Airmass Wx because, learning to soar, I wanted a forecast that shows not just whether the day will work, but where the lift will be, how high it goes and how far it will take my glider, and that is checked against real flights instead of taken on trust. My club was the first to test it, in September 2026, and it opened to everyone in October.

I check the forecast against what pilots actually fly: XC speed and distance against WeGlide flights in the US and the Alps, ridge lift and wave against WeGlide ridge and wave flights, and cloudbase against airport ceilometers. When it's off, I fix the model, not the numbers.

Will it be here in five years?

That's the plan, and it's built for it. The weather models it uses are free, open data, and the forecast is computed into static map files, so it costs little to run, and Pro subscriptions pay for it. No investors can pull the plug. I fly with it myself and keep improving it every week (see What's new). If Airmass Wx ever had to close, Pro subscribers would get notice and a refund for the time they'd paid for and not used.

Questions, ideas, or a day the forecast got wrong: write to me at eitanlev.steinberg@gmail.com. I answer every email myself.

Soaring forecast: gliders, hang gliders, paragliders

• Thermal forecast: thermal strength (as W*, the updraft speed RASP calls Thermal Updraft Velocity, or as your glider's climb: W* less its circling sink), height of thermals above the ground, thermal width, and the thermal type: continuous columns, bubbles, bursts, cloud streets, or thermals broken by wind shear.
• Clouds: cumulus cloudbase, cumulus depth and overdevelopment, a Cloud Layers by cloud type (blue thermals, cumulus humilis, mediocris, congestus, cumulonimbus, showers, stratus, stratocumulus, fog), and cloud cover at low, middle and high levels.
• Cross-country: XC speed and potential flight distance for your glider (still air or round your course), glide range in the wind and an XC task planner with the best start time.
• Thermal Triggers: where thermals are likely to break away, from the sun on each slope (with terrain shadows), land cover, snow and the day's heating.
• Ridge soaring: ridge lift and lee sink at 100 m terrain resolution, how high the ridge lift reaches for your glider, and high-resolution wind 100 m above the ground.
• Wave soaring: our own trapped lee-wave model, wave conditions (the Scorer checklist), lee wavelength, the model's vertical motion at altitude and a wave cross-section.
• Soundings and profiles: Skew-T soundings anywhere, an atmospheric profile (windgram) of the day's thermals, cloud and wind by height, and a point forecast with a meteogram.
• 3D map: the forecast draped over the terrain with thermals, cumulus, wave and sink drawn in the air; play the hour to watch thermals rise in cycles and cumulus form, drift with the wind and fade.

Aviation weather for GA pilots

• Flight rules (VFR, MVFR, IFR, LIFR), ceiling, visibility and cloud tops.
• Winds aloft at every flight level, surface wind and gusts, low-level wind shear.
• Icing potential, freezing level, clear-air turbulence, precipitation type and simulated radar.
• FAA sectional and IFR charts, airspace, airports, METARs, TFRs, NWS warnings and SPC outlooks.
• A route planner with a nav log, climb and descent, the best altitude, terrain clearance and a briefing along the route.

Ceiling, visibility, cloud tops, precipitation type and simulated radar come from each model's own fields. Icing is a potential (how likely supercooled cloud is) from cloud water or humidity between 0 and −20 °C, with freezing rain shown on its own; turbulence is the Ellrod clear-air index above the boundary layer. The route planner clears the real terrain within 4 nm of the route. Charts are for reference, not navigation: always use current official charts and publications (FAA, or your country's AIP).

Live weather

Radar loops (NEXRAD and MRMS), GOES GeoColor satellite, METAR observations blended into the forecast for the hours near now, and NWS storm warnings.

Where the forecast comes from

The forecast is computed after every model run from NOAA HRRR (3 km, the next 2 days) and NOAA GFS (up to 16 days) open data, ECMWF IFS (9 km, 15 days) open data, DWD ICON (0.125°, 7½ days) and ICON-D2 (2.2 km, 2 days over central Europe and the Alps) via Open-Meteo, all updated every 6 hours: Deardorff's convective velocity scale (W*) for thermal strength, a mixed-layer lifting condensation level for cloudbase, a moist parcel ascent for cumulus depth, potential flow over real terrain for ridge lift, the Scorer parameter for trapped lee waves, MacCready speed-to-fly for cross-country speed, and the mountain–plain circulation (“Alpine pumping”) the model grid misses. The results are served as static map tiles. More models and faster updates are on the way.

• Skew-T soundings and cross-sections: our own from HRRR, GFS, ECMWF and ICON-D2, else Open-Meteo.
• ECMWF forecast: Copyright © 2026 European Centre for Medium-Range Weather Forecasts (ECMWF). Source: www.ecmwf.int. Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence, from ECMWF's open data (its 9 km run, and its 50-member ensemble for the point forecast's chances and ranges) and, for its boundary-layer height, visibility and CIN, via Open-Meteo; our maps, soundings and point forecasts are derived from it (thermals, cloud, ridge lift and the rest computed from its fields). ECMWF does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use.
• ICON forecast: ICON data: Deutscher Wetterdienst (DWD), via Open-Meteo (CC BY 4.0).
• Radar and simulated radar: NOAA and the Iowa Environmental Mesonet. Satellite: GOES GeoColor from NOAA/NESDIS and NASA GIBS; visible from the Iowa Environmental Mesonet; earlier pictures over the Americas from CIRA SLIDER (Colorado State University / NOAA). Observations: METARs and PIREPs from aviationweather.gov. Warnings: the NWS and SPC. Smoke: HRRR.
• Charts, airports and airspace: the FAA's aeronautical open data (updated weekly), open flightmaps and openAIP; airports and navaids outside the US via OurAirports. TFRs are live from the FAA.
• Terrain: AWS Terrain Tiles. Satellite imagery for Thermal Triggers: Esri World Imagery.
• Land cover for Thermal Triggers: © ESA WorldCover project 2021 / Contains modified Copernicus Sentinel data (2021) processed by ESA WorldCover consortium (via Terrascope).

Coverage and price

HRRR covers the contiguous United States and nearby parts of Canada and Mexico. GFS and airports cover North America, Europe, Morocco, South America (Patagonia to Colombia and Venezuela, and Brazil outside the Amazon), southern Africa and New Zealand; GFS also covers Australia's gliding areas (the southeast, Queensland's east, Tasmania, Alice Springs and Western Australia's southwest). ECMWF (9 km) and ICON (13 km) cover the same areas as GFS, at two to three times its resolution; ICON-D2 (2.2 km) covers central Europe and the Alps. Airspace covers the US, Canada, Mexico and Central America, Europe (with Turkey and Israel), South America, southern Africa, Australia, Japan and New Zealand. VFR charts cover the US (FAA) and most of Europe (open flightmaps: not the UK, France or Spain); radar and IFR charts cover the US. The next 24 hours, most layers and live radar are free; a free account adds tomorrow, ECMWF and ICON; Airmass Wx Pro adds every layer, model and forecast day.