Weather Question: With Pics

Hello sorry if this is the wrong thread:

Well I have been outside most of the night running errands, and recently went to smoke a cigarette, and the whole evening I noticed that the clouds and wind was running a east to west motion. I live in Memphis Tennessee and usually the weather comes from Arkansas and holds a steady west to east motion, so tonight I decided to check the radar and I came across these images from the radar in the city.

First I checked my usual site source



and then I checked a second one to verify



I am not sure if this is normal, however I do check the weather from time to time and I have never spotted this type of weather pattern unless it was a tornado of some kind. Just looking for an educated answer, I don't believe it is something heinous just maybe a software style I have never seen.

reply to post by Aziroth


Aziroth.....

Notwithstanding you should ask an expert such as our own OzWeatherman.....

I have seen similar "circular" patterns occur when the rain is very heavy & the radar does not penetrate the very heavy rain as well over a distance.

Perhaps it's something like that.

Kind regards
Maybe...mnaybe not

Thats normal. It has something to do with the city, some cities can affect the weather. It was explained to me one time because I always see that over the city of Cleveland when I check the radar.

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The pattern shown there may have something to do with where the radar is located,example, if the radar is located on top of a hill and the rain is at that same height it will create what is called noise

this looks like the cloud was right at the radar level and only heavier rain was able to penetrate the radar noise and show itself

reply to post by Aziroth


So, Im assuming there was no rain at the time?

Where was it,and what date and time was it? I would like to check the weather balloon data, as I have an idea, but need that data to verify it

reply to post by OzWeatherman


OzWeatherman.....

So, Im assuming there was no rain at the time?

So apart from the fact I said the radar was blocking the rain, was I close?

Cheers mate
Maybe...maybe not

reply to post by Maybe...maybe not


Its possible

Heavy showers to obscure the pattern in any direction. You cant really tell what the intensity is, if the rain is all around you, and it often shows up as a big circular shape, with the radar being the central point

I believe that is what Meteorologists term 'ground clutter'.

From Wiki:

"...Clutter (also termed ground clutter) is a form of radar signal contamination. It occurs when fixed objects close to the transmitter—such as buildings, trees, or terrain (hills, ocean swells and waves)—obstruct a radar beam and produce echoes. The echoes resulting from ground clutter may be large in both areal size and intensity. The effects of ground clutter fall off as range increases usually due to the curvature of the earth and the tilt of the antenna above the horizon. Without special processing techniques, targets can be lost in returns from terrain on land or waves at sea.

Clutter is used by the military to jam radars by the use chaff. Chaff is small reflective material used to hide troop, ship, or aircraft movements by creating many returns and overwhelming the radar's receiver with spurious targets"

~TCT~

reply to post by The Cloud Taster


It is also caused by low cloud, and virga (precipitation not reaching the ground). Thats why I was asking about the cloud height. As maybe..maybe not said earlier, heavy rain also obscures or distorts the radar reading.

As for chaff, we had a well known case where one of our radars actually tracked an F-111 fighter jet through its chaff and electronic counter measures, lol. The military ended up calling the guy who did it, asking what radar we were using,

reply to post by OzWeatherman


There was no rain in the area it was more or less a clear night, there were a few low level wispy clouds but other than that there was nothing notable. The ground clutter idea sounds plausible, however where the radar unit is at there is not much more than trailer parks and a medium sized military base, the Millington naval support activity, would this be enough to cause that? In fact here in memphis the only area with large buildings is south near mississippi, and downtown on the river.

Edit to add: Also it was about 10 minutes before I posted last night, was heading to bed but I decided to post before hand.

I live in Indiana and use to live in Kentucky, just as in Tenn our systems and wind usually go from west to east, I have known of it changing but not often. If I recall it was usually when a strong weather pattern was on the east coast pushing against anything coming in from the west.

Ground clutter on the radar use to confuse me until I realized it looks different than actual rain.