Consistency of rain radar intensity

[BenW]

Something I have noticed on several occasions in the past is that the intensity of rainfall showing on the radar in a large area off the south west coast of England suddenly changes between 5 minute increments. The jump seems to be more than natural - it's hard to believe that rain actually increases by 4mm/hr simultaneously and uniformly over a 100sqm area. I recorded a video clip which will hopefully work. If you look at the area of heavy rain south west of my location (the triangle) it suddenly increases between the 4th and 5th step.

I wondered if there is any technical explanation for this? 

[Paul]

You're quite close to a radar site there, which is likely to have a bit of an effect - you can see to the north where trees/buildings etc are blocking the beam. 

Understanding Weather Radar

WWW.NETWEATHER.TV

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How does the rain radar work? There is a network of radar stations across the UK and Ireland scanning the skies and outputting images showing rain, snow and thunderstorms helping the weather forecast.

 

[ANYWEATHER]

10 hours ago, BenW said:

Something I have noticed on several occasions in the past is that the intensity of rainfall showing on the radar in a large area off the south west coast of England suddenly changes between 5 minute increments. The jump seems to be more than natural - it's hard to believe that rain actually increases by 4mm/hr simultaneously and uniformly over a 100sqm area. I recorded a video clip which will hopefully work. If you look at the area of heavy rain south west of my location (the triangle) it suddenly increases between the 4th and 5th step.

I wondered if there is any technical explanation for this? 

Your location is Exmoor , so I would presume it's something to do with orographic lifting? 

[Sprites]

The precipitation type showing hail/snow also has not worked for a few months. Is this still available on the free radar? 

 

[ANYWEATHER]

13 minutes ago, Sprites said:

The precipitation type showing hail/snow also has not worked for a few months. Is this still available on the free radar? 

 

Yes, I use it ,well it worked last time I used it anyway......☺

[BenW]

I made another recording, this time just toggling forwards and backwards either side of the jump. It occurs across a very wide area not just over ground or near the radar head so nothing to do with that. It's almost like the scale changes.

[Paul]

39 minutes ago, Sprites said:

The precipitation type showing hail/snow also has not worked for a few months. Is this still available on the free radar? 

 

It's all working - hail has never been picked in its entirety, and obviously we've not had any snow to show since the spring - that ought to re-appear this weekend. 

3 minutes ago, BenW said:

I made another recording, this time just toggling forwards and backwards either side of the jump. It occurs across a very wide area not just over ground or near the radar head so nothing to do with that. It's almost like the scale changes.

I think it's literally just more of the rain moving closer into the radar site, probably not helped by the fact that the Shannon radar site is out of action right now, which would help to smooth things better if it were also being used in the composite. 

[BenW]

5 minutes ago, Paul said:

I think it's literally just more of the rain moving closer into the radar site...

But if that were the case wouldn't you expect to see rain close to the radar head increase by more than rain further away? What I'm seeing is rainfall in the sea 150 miles west of the radar head suddenly increasing by exactly the same amount as rain at the radar head.

[Paul]

When the Met Office create the composite, they may well be making adjustments to allow for the lack of coverage from the Shannon, as they're essentially stitching all of the data from the single radar sites together. It's maybe something you'd need to raise with them for the exact details, as we're simply showing the data they're providing in that respect. 

[Downburst]

The new and apparently much improved Shannon radar should be online before end of this month. So the temp radar while Shannon was being replaced should be no more very shortly. All in all better data to come.

[Sprites]

1 hour ago, Paul said:

It's all working - hail has never been picked in its entirety, and obviously we've not had any snow to show since the spring - that ought to re-appear this weekend. 

I think it's literally just more of the rain moving closer into the radar site, probably not helped by the fact that the Shannon radar site is out of action right now, which would help to smooth things better if it were also being used in the composite. 

OK 

I will check it when hail is around again. It used to work a few months back.