🗺️ Visual reference

Weather map symbols

Cold fronts, warm fronts, station-model plots, radar codes and severe weather icons — the visual language of surface analysis.

Fronts

Cold front
Blue line with triangles pointing in direction of motion. Cold air replacing warm.
Warm front
Red line with semicircles pointing in direction of motion. Warm air replacing cold.
Occluded front
Purple line with alternating triangles and semicircles. Cold front catching up to warm.
Stationary front
Alternating blue triangles (north side) and red semicircles (south side). Little motion.
Dryline
Brown scalloped line marking boundary between moist and dry air. Common tornado trigger.
Trough
Dashed line marking elongated low-pressure axis. Often trigger for storms.

Pressure systems

H
High pressure
Red "H." Center of anticyclone. Fair weather, clockwise flow (N. Hem.).
L
Low pressure
Blue "L." Center of cyclone. Stormy weather, counterclockwise flow (N. Hem.).
Isobar
Curved line connecting points of equal pressure. Tight spacing = strong winds.

Station-model plot

One weather station's data in a single symbol. Wind barb points from where the wind is coming, temperature and dew point on left, pressure top-right.

7568052
Full station plot
Circle = cloud cover. Line = wind direction. Barbs = wind speed (10 kt each). Numbers = T / Td / pressure.
Wind barbs — 25 kt
Each full barb = 10 kt. Half barb = 5 kt. Filled triangle = 50 kt. Add them up.
Wind barbs — 50 kt
A filled triangle (pennant) represents 50 knots. Add remaining barbs.
Cloud cover — clear
Empty circle = clear sky.
Cloud cover — overcast
Fully filled = overcast. Half-filled = partly cloudy.

Radar reflectivity

The classic scale from clear air (blue) to strong storms (magenta) measures how much energy a radar beam gets back.

5-15 dBZ
Light drizzle, clear air return, dust. Not weather-significant.
20-30 dBZ
Light rain. Typical stratiform cloud precipitation.
40-50 dBZ
Heavy rain, marginal severe. Thunderstorm territory.
55-65 dBZ
Severe thunderstorm core. Likely hail.
70+ dBZ
Very large hail or lofted tornado debris (TDS).

Severe weather icons

🌪️
Tornado warning
Red polygon on radar. Take shelter immediately.
⛈️
Severe thunderstorm
Yellow polygon. Hail ≥1" or winds ≥58 mph.
💧
Flash flood
Green polygon. Life-threatening flooding imminent.
❄️
Winter storm
Purple polygon. Significant snow / ice.

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