Portland, ME Weather Radar and Cloud Cover

dBZ stands for decibels of Z, where "Z" refers to the radar reflectivity factor, which measures the strength of the radar signal reflected back to the radar from precipitation particles like rain, snow, or hail.

dBZ is a logarithmic scale (i.e. exponential growth) that quantifies the amount of energy reflected by objects (typically raindrops, snowflakes, or other hydrometeors) in the atmosphere. The higher the dBZ value, the stronger the reflected signal, which typically means heavier precipitation; the contrasting colors on the radar maps above help visualize intensity and type.

Here's how dBZ values relate to the intensity of precipitation:

• 10-20 dBZ: Light rain or very light precipitation.
• 20-30 dBZ: Moderate rain or light snow.
• 30-40 dBZ: Heavy rain or moderate snow.
• 40-50 dBZ: Very heavy rain, potential for hail or strong thunderstorms.
• 50+ dBZ: Extreme precipitation, often associated with intense thunderstorms, tornadoes, or hailstorms.