ParaglidingWX — Windgram

Windgram

Open a windgram from a takeoff marker or use Windgram pick-mode and click the map. For a classic single-hour sounding diagram, see Skew-T. Windgrams are available for HRDPS ~1 km West, HRDPS 2.5 km, RDPS 10 km, and HRRR ~3 km (CONUS) (see Weather models). Height axes show metres with a companion feet scale at major ticks.

On every tab except Notes, the chart shares the same frame: precipitation-probability and low / mid / high cloud-fraction strips above the plot; two 10 m wind rows and a gust row below (with a dashed line at takeoff elevation on the main plot). Most tabs also have an ⓘ button in the header with the same keys as below.

Wind

The main plot is wind speed and direction by height (arrows show where the air flows; size scales with speed). Above the plot, this tab adds Solar and Lift strips under the cloud bands.

• Solar — Model shortwave radiation reaching the surface. Dark means weak heating (night or heavy cloud); bright means strong sunshine.
• Lift — A thermal-updraft scale (m/s), using the same parcel physics as the Parcel buoyancy tab. When the model supplies surface sensible and latent heat fluxes (GFS, HRRR, most ERA5-based runs), Deardorff w* is used (consistent with Canada RASP). Where fluxes are unavailable (HRDPS, ICON, some ECMWF runs), Lift falls back to √(CAPE / 100).
• Mixing depth — When the model does not supply boundary-layer height, mixing depth uses the same estimate as the Parcel tab’s BL top (est.): oversampled buoyancy, vertical box blur, then LCL from 3-hour smoothed 2 m temperature and humidity combined with the highest altitude that still has smoothed buoyancy > 0. If there is no positive smoothed buoyancy in that column, Lift is forced to 0.

Lapse Rate

Background colour shows the local lapse rate (°C per 1,000 ft) between adjacent model levels — the same scale as the Canada RASP windgram. The dry adiabatic lapse rate (DALR) is −3 °C/1000 ft (−9.8 °C/km); air below that boundary is absolutely unstable.

• < −3 — super-adiabatic (absolutely unstable)
• −3 to −2.5 — very unstable
• −2.5 to −2.0 — unstable
• −2.0 to −1.5 — moderately unstable
• −1.5 to −1.2 — conditional instability
• −1.2 to 0 — stable
• 0 to +0.5 — near-inversion
• > +0.5 — temperature inversion

Parcel buoyancy

A surface air parcel is lifted from takeoff elevation. It cools at the dry adiabatic lapse rate (9.8 °C/km) until the LCL (lifting condensation level — where cloud forms), then at the slower saturated adiabatic lapse rate above. Colour shows T_parcel − T_environment: positive (warm colours) means the thermal is still buoyant; negative (cool colours) means it has been capped.

• > +4 °C — very strong buoyancy
• +2 to +4 °C — strong
• +0.5 to +2 °C — good
• 0 to +0.5 °C — marginal / near thermal ceiling
• −1 to 0 °C — slightly stable
• −3 to −1 °C — stable
• < −3 °C — strong inversion

White line — LCL (cloud base): height at which the rising parcel saturates. Below it thermals are dry; above it condensation releases latent heat and thermals can climb further.

Black line — BL top: from the model’s boundary-layer height when available (e.g. HRDPS ~1 km). On HRDPS ~2.5 km the chart uses BL top (est.) — mixing depth from the same oversampled, smoothed buoyancy pipeline, combined with LCL from 3-hour smoothed 2 m temperature and humidity (minimum 80 m AGL to draw). The Wind tab Lift strip uses the same smoothed mixing depth when the model does not supply BLH.

Temperature

Colour shows model air temperature (°C) at each altitude on the same pressure levels as the wind profile. Values are oversampled in time and height and smoothed with a vertical box blur (same pipeline as Parcel buoyancy) so small-scale layer noise is softened. Between the ground and the lowest model level, temperature is blended from 2 m temperature to the first isobaric level. Colours run in 5 °C steps from −30 to +30 °C (blue = cold, red = warm).

Clouds

The main plot uses model cloud cover % at each pressure level: dark = clear air, light = thick cloud. Precipitation probability and the low / mid / high rows (shared with other tabs) sit above the plot; a Solar strip (same scale as on the Wind tab) appears below those rows. There is no Lift row on this tab.

• Low (surface – 3,000 m) — cumulus, fog & low stratus
• Mid (3,000 – 8,000 m) — alto-stratus / alto-cumulus
• High (> 8,000 m) — cirrus & high ice cloud

Darker shading in the low / mid / high rows means more total cloud fraction in that layer.

Airspace

Vertical profile of charted airspace at the windgram site (OpenAIP data, same view as the map Airspace vertical profile). Airspace varies horizontally — use the map overlay as well as this slice. See Airspace for overlay toggles and limitations.

Notes

Read-only hints from the site entry in configuration (local launches and ParaglidingEarth imports). No forecast chart is drawn on this tab.

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