Aviation weather center

Radar reflectivity (precipitation intensity)

NEXRAD base reflectivity, dBZ — NOAA / Iowa Environmental Mesonet

• 5–20 dBZ — Light precipitation / drizzle
• 20–35 dBZ — Light to moderate rain
• 35–45 dBZ — Moderate rain
• 45–50 dBZ — Heavy rain — convection likely
• 50–60 dBZ — Very heavy rain / thunderstorm core
• 60+ dBZ — Extreme — hail probable, avoid

Reflectivity shows precipitation only. It does not show cloud, icing or turbulence, and the mosaic lags real time by several minutes.

Satellite — infrared cloud tops

GOES infrared brightness temperature — NOAA

• Warm tops — Low cloud or clear ground, near-surface temperature
• Mid tops — Mid-level cloud
• Cold tops — High cloud, cirrus or deep convection
• Very cold tops — Overshooting / strong convective tops

Infrared works day and night and reads cloud-top temperature. Colder tops usually mean higher, more vertically developed cloud.

Satellite — visible

GOES visible imagery — NOAA

• Dark — Clear ground or water
• Grey — Thin or broken cloud
• Bright white — Thick cloud, convection or snow cover

Reflected sunlight, so it is daylight only and goes dark after sunset. Brighter equals thicker or more reflective cloud; snow also appears bright.

Flight categories at reporting stations

Derived from the METARs held in this workspace

• VFR — Ceiling > 3,000 ft AGL and visibility > 5 sm
• MVFR — Ceiling 1,000–3,000 ft and/or visibility 3–5 sm
• IFR — Ceiling 500–999 ft and/or visibility 1–3 sm
• LIFR — Ceiling < 500 ft and/or visibility < 1 sm

Ceiling and visibility categories, coloured per station. Read each station's own observation time — a category is only as current as its METAR.

Hazard advisory polygons (official viewers)

NWS Aviation Weather Center / FAA

• AIRMET Sierra — IFR conditions and mountain obscuration
• AIRMET Tango — Moderate turbulence, strong surface winds, low-level wind shear
• AIRMET Zulu — Moderate icing and freezing levels
• SIGMET — Severe, non-convective hazards to all aircraft
• Convective SIGMET — Thunderstorms, embedded/line/severe convection
• TFR — Temporary flight restriction — check the FAA notice before flight

These polygons are not drawn in this app. The colours below are the conventions used on aviationweather.gov so the official viewer reads the same way.