The Radar page

radar pulls tiles from:

• UK NetWeather composite for reflectivity.
• Met Office DataHub where available for velocity (dual-pol CC/ZDR pending integration).
• Our own SOS cell-tracking algorithm for mesocyclone flags.

Cells with persistent >45 dBZ cores > 3 volumes are tracked and labelled with motion vectors. A velocity couplet exceeding gate-to-gate thresholds raises a TVS flag on the map.

Analysis panel

The Analysis section in the layer controls gives access to six instability and wind overlays, all refreshed every 15 minutes from Open-Meteo and the Wind Atlas:

• Jet stream — upper-level jet core positions and speeds (kt), derived from ADS-B aircraft data. High speeds overhead correlate with divergence aloft and enhanced deep-layer shear.
• Shear fuel — 0–6 km bulk wind shear grid. LOW/MOD/HIGH tiers; a HIGH tile means the atmosphere has the rotation potential for organised supercell structure.
• CAPE — Convective Available Potential Energy on a 0.5° grid. The map shows current-hour values during the convective day; at night it falls back to the day's peak (09–21 UTC) so the layer remains useful for planning. See cape.
• Lifted Index — LI on the same 0.5° grid. Only unstable cells (LI < 2) are drawn. See lifted-index.
• K-Index — Classic European thunderstorm likelihood index on a 1° grid. More sensitive to low-level moisture than CAPE — often the cleaner signal for UK conditions. KI ≥ 20 is the storm-possible threshold; ≥ 30 means widespread convection. See k-index.
• Synoptic — Surface pressure contours or 24 h rainfall accumulation from the Met Office UKV model.