The optical range of a weather radar is limited to 5 - 200 kilometers (3 -124 miles).Here are a few of the most notable drawbacks: With all the advantages and benefits of the weather radar, they are not without their shortcomings or limitations. This helps anyone viewing the picture to know when the image was created, no matter where in the world or in which timezone they are. The two terms are often used interchangeably, which can be confusing.īe sure to read the weather scale that accompanies every radar image to confirm what each color means for that specific image.Įach radar image has a timestamp at the bottom of the image, which is in Universal (Greenwich) Time or UTC. (In many cases, black represents hail.)Ĭolor scales are also used to indicate the amount of rainfall, not just the intensity. Usually, the most intense form of precipitation is indicated by black. On modern-day weather systems, the results captured by a weather radar are displayed as a color image on a display screen.Ī color scale is used to show the intensity of the precipitation. The resulting animated radar image forms a thirty-minute loop.Īlthough a radar image does not give you a clear and definite forecast, it shows you where the rainfall has been, as well the direction in which it may be moving.
The strength of the echo, on the other hand, provides a strong suggestion of the type of precipitation encountered (rain, hail, or snow).Īlthough this varies from one radar to another, a signal is normally sent out with a frequency of around once every six to ten minutes. The length of time it takes the echo to return to the sender indicates how far away the precipitation is from the radar. The radar can determine a lot from the characteristics of the reflected wave. If the radar animation of the last hours shows local thunderstorms or precipitation cells forming and disappearing in an irregular manner, then the forecast is not vey accurate.If the signal encounters any precipitation (rain, hail, or snow), it is reflected back to the radar tower, which interprets the reflected signal (also called the echo). The forecast works very well when weather fronts or large organized precipitation structures are moving regularly, without disappearing or being created.
Real weather is more complex than just the displacement of existing precipitation cells. Longer forecasts are not possible, as new precipitation cells are developing or existing ones are disappearing within a short time. This so called precipitation nowcast is the most accurate precipitation forecast possible but the forecast horizon is limited to about an hour. The rain/snow forecast is computed by estimating the movement of precipitation cells observed by radar and extrapolating this movement into the future. Philippines: How accurate is the radar based forecast? Moreover, some countries do not operate a weather radar network, and in those countries satellite data is used to estimate rainfall, which is less accurate than a realtime weather radar. Note that lightning is not shown on the forecast, as it cannot be predicted. Light blue indicates drizzle, blue a medium intensity, and red and yellow indicate very strong precipitation, usually associated with thunderstorms.Ĭurrent lightning strikes are marked with small orange dots on the map (Europe only). The different colours indicate the intensity of rainfall or snowfall. The radar map is updated every 5 minutes with a new radar observation. The weather radar ( Philippines) shows where it is currently raining or snowing.
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