Interactive Thermodynamic Sounding, Parcel Trajectory & Inversion Workbench
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Choose from 4 free meteorological data sources. Both IEM and University of Wyoming archives update through today's latest 00Z/12Z radiosonde launches (and automatically step back 12h if today's balloon is still ascending).
Drag the yellow TL (Top-Left) and BR (Bottom-Right) handles on the image to match the chart's pressure & temperature bounds.
Use Auto-Scan or click points along the Temperature and Dewpoint curves on the image.
Edit the sounding text directly below to modify levels, or download as CSV / Wyoming text.
Designed by German meteorologist Georg Stüve (1927), the Stüve diagram plots Temperature (T) linearly on the horizontal axis and Pressure scaled to $P^{0.286}$ ($R_d/c_p$) on the vertical axis. Because of Poisson's equation, dry adiabats ($\theta$) are completely straight lines, making parcel trajectories easy to read without skewed axes.
When an unsaturated air parcel starts at $(P_0, T_0, Td_0)$ and rises:
• Its temperature cools along a straight Dry Adiabat ($\theta$) ($\approx 9.8^\circ\text{C/km}$).
• Its dewpoint follows a constant Saturation Mixing Ratio line ($w_s$).
• Where those two lines intersect is the Lifted Condensation Level (LCL) — the parcel reaches 100% RH and a cloud base forms!
• Above the LCL, latent heat release slows cooling, so the parcel follows a curved Moist Adiabat ($\theta_w$).
Compare the Parcel Temperature ($T_p$, orange line) to the Environment Temperature ($T$, red line) at the same pressure:
• If $T_p < T_{\text{env}}$, the parcel is colder/denser than its surroundings (stable / negative buoyancy, shaded blue as CIN).
• The crossover where the parcel becomes warmer than the environment above the LCL is the Level of Free Convection (LFC).
• Above the LFC, $T_p > T_{\text{env}}$, so the parcel accelerates upward on its own (positive buoyancy, shaded red as CAPE) until it crosses back at the Equilibrium Level (EL) (near the anvil top).
Normally temperature decreases with altitude. A layer where temperature increases with altitude (the red $T$ line slopes to the right as you go up) is a Temperature Inversion (highlighted in amber). Rising air parcels quickly become colder than the warm inversion air above them, acting as a "lid" that traps pollutants, marine fog, or suppresses thunderstorms.