this post was submitted on 25 Jul 2024
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Why are the rain clouds shaped in this way? (feddit.org)
submitted 3 months ago by Peter_Arbeitslos@feddit.org to c/weather
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A bug in the matrix or just the radar? This is no normal cloud-shape, is it?

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[–] wren 7 points 3 months ago* (last edited 3 months ago) (1 children)

looks a bit like convective cells to me! they happen in summer (as long as there is sufficient surface heating to drive the convection) - they're like bubbles in boiling water.

It looks like you've got high pressure over there though... the high pressure may just limit the cloud heights and intensity of the precipitation?

Edit: these look a little too big to be pop-up cells, but they still look more convective (instead of frontal). a bit suspiciously too round, though. Do they stay consistent and track across the sky, or are they more bubble-like?

2nd edit: looks like I'm wrong and it is a radar artefact :) (this is why looking at radar timelapses is more important than just single-frames!)

3rd edit: it's not an artefact, it's a real signal! it's insects!

[–] Umbrias@beehaw.org 2 points 3 months ago (1 children)

what a roller coaster, and the ominous unexplained insect edit is a cherryon top

[–] wren 1 points 3 months ago

aha here's a full explanation of the thought process:

  • no other weather report matches these patterns
  • they're suspiciously round and not blobby like real clouds
  • they're each suspiciously localised around the radars in the network
  • there are lots of types of radar artefacts, including close-to-radar ground-clutter (this is what I assumed it was) but it's too consistent and large of a signal for that
  • so it must be something uniform, in the air instead of on the ground, that isn't rain
  • bugs are about the size of a big rain drop! enough to be picked up as a strong signal by the radar and enough to prevent the radar from seeing long distances
  • It's also been flying-ant-day recently across Europe
[–] fauxerious@lemmy.world 6 points 3 months ago (2 children)

A lot of weather radars have localized noise, I’ve noticed

The screenshot below has only one radar selected. Maybe the app you are using is displaying data from more than one radar?

https://lemmy.world/pictrs/image/e58e2f13-f75a-454c-b8c1-44f0f306fd55.png

[–] wren 6 points 3 months ago* (last edited 3 months ago) (1 children)

Oooh, excellent point! The german weather service (DWD, which OP is using) has 17 operational weather radar... looks like an artefact to me!

EDIT: it's not an artefact, but insects!

[–] Emperor 4 points 3 months ago (1 children)

Bingo! Nice find.

[–] wren 2 points 3 months ago* (last edited 3 months ago) (2 children)

Wait, I'm wrong yet again!!!! "A bug in the matrix" in the description should have clued me in...

The DWD network is surely more reliable than this, and it's nice high pressure, so it's rain-free and plenty of updrafts, so it's perfect conditions for insects!! They cause enormous signals, no idea why I didn't think of it first.

(Seen recently in the news in the UK here )

[–] Peter_Arbeitslos@feddit.org 2 points 3 months ago (2 children)

Damn, I thought insects was some English meterological term for special clouds, but really? Insects? Thats kind of amazing!

[–] wren 2 points 3 months ago

Yeah, I don't know why I didn't think of it earlier!

One of my colleagues is doing radar bug-signal research. Supposedly, bugs show up as pretty bright signals on radar (similar size to raindrops!), and if you use doppler, you can pick up how fast the wind speed is by assuming the bugs are being transported by the wind

Also: lots of other fun things (bats, trains, smoke) show up on radar

[–] Peter_Arbeitslos@feddit.org 1 points 3 months ago

Sateliete from that point in time doesn't show the clouds either.

https://zoom.earth/maps/satellite/#view=50.668,10.116,6z/date=2024-07-19,13:15,+2

[–] Peter_Arbeitslos@feddit.org 1 points 3 months ago* (last edited 3 months ago)

I haven't heard about it, but it's the most reasonable explanation. The radars have been influenced by the swarms of insects, but only by those which were near to the radar-locations as it's described on the screenshot below.

The website is really old: https://www.radartutorial.eu/15.weather/wr22.en.html

[–] TragicNotCute@lemmy.world 3 points 3 months ago (1 children)

I don’t know my German geography, but I’d be curious how topology plays into this.

[–] wren 2 points 3 months ago

Doesn't look like orographic cloud to me! Usually they have ripples in em

Plus, the Alps are only really in the South and nowhere near Berlin (which is pretty flat) - so you'd see more enhancement in the South than the North, whereas these are pretty evenly spaced

[–] rwtwm 2 points 3 months ago (1 children)

The sat 24 IR view doesn't seem to match up very well with what you've posted, so it may just be noise, or a corrupted data load.

[–] Peter_Arbeitslos@feddit.org 2 points 3 months ago (1 children)

The screenshot is 6 days old.

[–] Peter_Arbeitslos@feddit.org 1 points 3 months ago

But the sateliete image of the above time and location doesn't really fit either.

https://zoom.earth/maps/satellite/#view=50.487,9.347,6z/date=2024-07-19,13:15,+2

[–] Vaginal_blood_fart 1 points 3 months ago

Clearly these are map markers for death camps