AMDAR soundings · SPC Day 1 outlook

What this is. A map of recent aircraft (AMDAR/ACARS) soundings over the NWS Storm Prediction Center's Day 1 Convective Outlook. Each gold dot is an airport where an ascending or descending aircraft has recently profiled the atmosphere; click one to see its Skew‑T / Log‑P and hodograph. The value tabs recolor the dots by low‑level parameters (bulk shear, precipitable water, cap strength, LCL and wet‑bulb‑zero height) to help spot where the near‑storm environment is coming together.

Why aircraft data. Balloon soundings launch only twice a day from a sparse network. Aircraft profile the same airport hubs every 30–60 minutes, so on an active afternoon you can watch the environment evolve between balloon launches. The tradeoff: coverage is irregular, only some aircraft report humidity, and sensors can err — so this is a supplement to, never a replacement for, official products and radiosondes.

How the values are derived.

• Shear (0–1 / 0–3 km): bulk difference of the wind between the surface and 1 km / 3 km, in knots.
• Precipitable water: integrated column moisture, anchored at the bottom with a model surface temperature/dewpoint; suppressed when an aircraft's humidity sensor fails a surface‑dewpoint quality check.
• Cap strength: the maximum temperature excess of the environment over a lifted surface parcel above the LCL — computed from the aircraft's temperature profile, so it's available even on aircraft without humidity.
• LCL height: lifting condensation level, using the aircraft's observed mixing ratio lifted from the model surface temperature (so it isn't biased low by the aircraft sampling above the surface layer).
• Wet‑bulb‑zero height: height of the wet‑bulb 0 °C level, a hail/melting parameter, by solving the psychrometric equation at each level.

Data sources (all public domain). SPC Day 1 outlook — NOAA/NWS SPC; aircraft soundings — NOAA MADIS ACARS profiles; surface and HRRR model fields — Open‑Meteo. This site is independent and not affiliated with or endorsed by NOAA.

Updates. Live data is fetched from NOAA and cached a few minutes, so the map reflects the most recent hour or two of aircraft soundings and the current SPC outlook. Use the window selector to change how far back soundings are drawn, and ↻ refresh to pull the latest.

Contact. Questions, corrections, or feedback: richmamrosh@gmail.com.

Disclaimer. Provided “as is,” for situational awareness and educational use only — not for operational forecasting or any life‑safety decision. Always rely on official National Weather Service warnings and guidance.