Marine & Coastal Weather from Maine Harbors
Long Range Composit
Boston, Massachusetts
  Images  Weather   Marine  ME NH MA RI
Base Composit 1 Hour Total Storm Total
Current Radar Image
Base Reflectivity Radar (S Rng)
A weather surveillance radar site sends out a beam of energy which reflects off objects (precipitation, clouds, trees, buildings, birds, etc.). Echoes from surface targets appear in almost all radar reflectivity images. "Ground clutter" generally appears within a radius of 20 nm. The maximum range of the "short range" base reflectivity radar is about 143 miles. To determine if precipitation is occurring at greater distances, select an adjacent radar, National radar composite or E Canada composite.

The amount of energy which is received back at the radar dish is measured in units of DBZ (decibels of Z - reflectivity). The higher the DBZ value the larger the object, i.e. large raindrops and hail produce high DBZ values. In general, DBZ values greater than 20 indicate areas where precipitation is reaching the ground.

Composite Reflectivity Radar (L Rng)

This product is used to reveal the highest reflectivity in all echoes. When compared with Base Reflectivity, the Composite Reflectivity can reveal important storm structure features and intensity trends of storms.

The maximum range of the "long range" composite reflectivity product is about 286 miles. However, only the most intense convective storms and tropical systems will be detected at the longer distances.

One-hour Precipitation

This is an image of estimated one-hour precipitation accumulation, used to assess rainfall intensities for flash flood warnings and special weather statements.

Storm Total Precipitation

This image is of estimated accumulated rainfall, continuously updated, used to locate flood potential, estimate total runoff and provide rainfall accumulations for the duration of the event.
For info about time (UTC, 24 hour, etc.) click here

Maine Harbors obtains forecasts and other information from the National Weather Service - (IWIN) and Environment Canada. US Forecasts are public domain and cannot be copyrighted. Canadian forecasts are copyright of Environment Canada.

Limitation of Liability - Maine Harbors does not warrant the accuracy, completeness, merchantability or fitness for a particular purpose of any of the weather information offered through this service. Under no circumstances shall Maine Harbors be liable to you or any other person for any indirect, special, incidental, or consequential damages arising from the use of this service.