What shows up best on radar, rain or hail?

Answer 1

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On a radar there are only three types of precipitation that are detected. They are rain (which is green), mix precipitation (rain/snow) (which is pink) and snow which is white. So the answer is rain.

Source(s):

I'm a weather fanatic

Answer 2

In fact ,rain reflects the radio waves from a radar more than any ice particle.But the problem with rain drops is the smaller size when compared to ice particles.Because, the smaller the size, the less will be the received signal strength.The melting particles(ice,snow, etc)are spheroidal in shape and have a larger surface area than raindrops.For a given wavelength,the strength of the received echo increases very rapidly with size(proportional to the sixth power of the diameter).A bigger ice particle may sometimes may reflect more than a small raindrop.
Moreover ,the wavelength used in a radar also plays an important part in determining the strength of the received signal,For example,a S-Band radar(wavelength of 10 cm)which is usually used to track cyclones/hurricanes can generally detect rain but not cloud droplets, whereas a K-Band radar(wavelength of one cm) can detect many clouds not containing any precipitation at all.
Attenuation of the to and fro signal by the atmospheric gases also plays a part in affecting the signal.Particularly ,the signal from the radars operating on small wavelengths (3 cms and below) will be attenuated more.
So ,many such factors shoud be taken into consideration while determining whether the siganal received form rain drops is more than that of the siganal received from ice particles.
Interestingly, a weather phenomena called a 'bright band' observed in RHI indicator(showing the Vertical cross section of the atmosphere) of the radar during widespred rain ,is a combination of both the reflectivity of the rain drops and the size of the ice particle.The explanation is given below.
The bright band appears just about 1000 feet below the freezing level(ie the height at which temperature becomes zero) in the atmosphere.During precipitation,when the snow or ice crystals fall below the freezing level ,they start melting and acquires a coating of water.so,the bigger ice particles ,in addition to their bigger size get the additional rain coating and hence the reflectively suddenly increases many fold and this makes a peak of reflectivity resulting in a bright horizontal line just below the freezing level.Below this bright band, the ice particles completely melt and become small rain drops resuting in less reflectivity.Moreover, the falling speed of the raindrops increases rapidly(about 5 times) below this bright band resulting in less concentration of water drops which in turn reduces the reflectivity further.So, both above and below the bright band, the reflectivity reduces showing the bright band predominantly.
Now you can come to your own conclusion whether rain reflects more or hail reflects more.

Answer 3

Hail has a stronger radar signature than rain.

Source(s):

I am a retired research meteorologist, Ph.D., with some 45+ years experience

Answer 4

Nothing shows up better than large, water covered hail. It is the most reflective of RF radiation from weather radars.

However, very large drop heavy rain is also very reflective and is one of the reasons it is desirable to have dual polarization which will be installed on most WSR-88D radars over the next few years which will even better distinguish between hail and large rain drops.

At the other end is very light snow. It did not even show up on the older weather radars and is still difficult due to overshooting beams at distance from the radar as well as it's light RF reflective characteristics.