Live doppler radar portland maine

The time period when the sun is no more than 6 degrees below the horizon at either sunrise or sunset. The horizon should be clearly defined and the brightest stars should be visible under good atmospheric conditions (i.e. no moonlight, or other lights). One still should be able to carry on ordinary outdoor activities.

The time period when the sun is between 6 and 12 degrees below the horizon at either sunrise or sunset. The horizon is well defined and the outline of objects might be visible without artificial light. Ordinary outdoor activities are not possible at this time without extra illumination.

The time period when the sun is between 12 and 18 degrees below the horizon at either sunrise or sunset. The sun does not contribute to the illumination of the sky before this time in the morning, or after this time in the evening. In the beginning of morning astronomical twilight and at the end of astronomical twilight in the evening, sky illumination is very faint, and might be undetectable.

The time of Civil Sunset minus the time of Civil Sunrise.

The time of Actual Sunset minus the time of Actual Sunrise. The change in length of daylight between today and tomorrow is also listed when available.

This Maine Emergency Management Agency link will take you to the latest National Weather Service predictions, forecasts and other weather information affecting Knox County, Maine and New England.

...Knox County EMA is a NOAA "Weather-Ready Nation" Ambassador organization

Get live and historical weather conditions now from the Knox County EMA Office

Today's Knox County weather forecast

Live NWS Weather Radar from Portland, Maine.  This is a live weather image which opens in a new window. (Note: This weather radar site has the new dual polarization capabilities.) 

Northeastern U.S. Weather Radar Mosiac.  This is a live looping weather image which opens in a new window.

Are you setting up a new NOAA All Hazards Alerting Weather Radio?

To receive specific alerts for Knox County you need to enter FIPS county code 23013 during setup. Local alerts are triggered from the Dresden (162.475) and Ellsworth (162.400) NOAA Weather Transmitters. Frequency and channel settings may vary depending on manufacturer. Please refer to your owners manual for more info.

Watches, Warnings and Advisories.  What's the difference?

     Watch-A watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still uncertain. It is intended to provide enough lead time so that those who need to set their plans in motion can do so.

     Warning- A warning is issued when a hazardous weather or hydrologic event is occurring, is imminent, or has a very high probability of occurring. A warning is used for conditions posing a threat to life or property.

     Advisory- An Advisory highlights special weather conditions that are less serious than a warning. They are for events that may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property.

What IS the difference between a Thunderstorm Watch and a Warning? 

A severe thunderstorm Watch means that conditions are favorable for development of a severe  thunderstorm in or close to the watch area. Severe thunderstorms may produce large hail or damaging winds. When a watch is issued, you should review thunderstorm safety rules and be prepared to move to place of safety if threatening weather approaches. Keep an eye to the sky and an ear to the National Weather Service's weather radio or local radio and television stations for further updates and possible warnings.

A severe thunderstorm Warning, on the other hand, means that a severe thunderstorm is occurring or is imminent in the Warning area based on doppler radar information or observation by a trained weather spotter. You should move indoors to a place of safety. Schools should think about delaying departure of buses, and should take quick action to delay outdoor sports activities, etc.

Storm Surge explained.  "Storm Surge" is an abnormal rise of water generated by a storm, over and above the predicted astronomical tide produced by water being pushed toward the shore by the force of the winds moving around a storm. A "Storm Tide" is the combination of both storm surge and the astronomical tide. Storm Surge, Storm Tides or Coastal Flooding can be deadly!  Nine out of ten deaths from hurricanes can be attributed to these storm phenomena.  

Portland, Maine Area Composite Reflectivity Radar

How to Use the Radar Map

To use the Zoom feature, click on the upper left "less than" symbols, or click on the plus and minus symbols. Clicking on the + symbol zooms in, the - symbol zooms out. The default symbol is highlighted in yellow. Clicking on the larger symbols to the left will zoom you in, clicking on the smaller symbols to the right will zoom you out.

To Animate the radar map click on "Animated:OFF", To see weather advisories clicking on "Advisories:Off" for the alerts map (zoomable), clicking on "Track:OFF" will show the storm tracking, & by clicking on "Lightning:OFF" will show all lightning strikes on the map.

On the very bottom of the graphic you will find the "Additional Weather Maps" menu. These map options include weather fronts, jet stream, visible satellite, IR satellite, wind, temperatures, humidity, dew point, heat index, wind chill, snow depth, visibility, air quality, uv, and flu maps.

The colors are the different echo intensities (reflectivity) measured in dBZ (decibels of Z) during each elevation scan. "Reflectivity" is the amount of transmitted power returned to the radar receiver. Reflectivity (designated by the letter Z) covers a wide range of signals (from very weak to very strong). So, a more convenient number for calculations and comparison, a decibel (or logarithmic) scale (dBZ), is used.

The dBZ values increase as the strength of the signal returned to the radar increases. Each reflectivity image you see includes one of two color scales. One scale (far left) represents dBZ values when the radar is in clear air mode (dBZ values from -28 to +28). The other scale (near left) represents dBZ values when the radar is in precipitation mode (dBZ values from 5 to 75). Notice the color on each scale remains the same in both operational modes, only the values change. The value of the dBZ depends upon the mode the radar is in at the time the image was created.

The scale of dBZ values is also related to the intensity of rainfall. Typically, light rain is occurring when the dBZ value reaches 20. The higher the dBZ, the stronger the rainrate. Depending on the type of weather occurring and the area of the U.S., forecasters use a set of rainrates which are associated to the dBZ values.

These values are estimates of the rainfall per hour, updated each volume scan, with rainfall accumulated over time. Hail is a good reflector of energy and will return very high dBZ values. Since hail can cause the rainfall estimates to be higher than what is actually occurring, steps are taken to prevent these high dBZ values from being converted to rainfall.