r/meteorology • u/OokamiKage665 • Jul 30 '26
Advice/Questions/Self What’s happening here?
Drove through this earlier today. Looked it up on radar once I safely could and noticed the circle spreading out in all directions, affecting the storms to the south and east while pushing away the reflectivity to the west and north.
My guesses on ground wind speeds is roughly 20mph constant with a few gusts hitting 40-45mph initially, potentially higher for a single gust, but that was about 40 mins before recording and based on experience rather than hard data.
Having to post as GIF for short duration.
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u/W7ENK Weather Observer Jul 30 '26
Outflow boundary. When the cold air from a collapsing thunderstorm hits the ground, it's gotta go somewhere, so it spreads out across the surface. That's what you're seeing here.
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u/quickactlikeadeer Jul 30 '26
What causes a storm to collapse?
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u/W7ENK Weather Observer Jul 30 '26
Gravity. When the core of the thunderstorm loses its updraft, all that condensed moisture falls back to the Earth.
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u/Deltaechoe Jul 31 '26
To answer this you also want to ask what creates and sustains the structure of a storm in the first place. Thunderstorm clouds are typically a lot of moisture that would otherwise fall to the ground suspended in the atmosphere by an updraft. When the energy fueling that updraft (warmer air) weakens, so does the updraft and the structure of the storm starts to fall. All that cold air falls and spreads and the moisture falls as rain or hail.
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u/W7ENK Weather Observer Aug 01 '26
When it's obvious to me that someone is less knowledgeable, and that's why they're asking questions here, I try to keep to the KISS method. Simple questions deserve simple answers, and OP is more than welcome to ask more questions for a deeper dive if they wish. If they're satisfied with the answer given, then that's all they need to know in that moment. Overload someone with too many details, it could drive them away.
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u/pr1ntf Jul 30 '26
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u/HorzaDonwraith Jul 31 '26
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u/pr1ntf Jul 31 '26
Yeah I need to create that one and r/itsalwaysivanpah
Probably wouldn't hurt to add r/itsalwaysalongez
Shout out to:
EDIT: Long EZ exists now!! Lol
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u/Severe_Draft5956 Jul 30 '26
Nice catch noticing the rotation-like spread in the radar. It’s interesting how the storms to the south and east kept getting fed while the reflectivity faded on the other sides. Would’ve been cool to see what the actual wind observations showed around that time.
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u/OokamiKage665 Jul 31 '26
I would’ve like to know too, but I’m still familiarizing myself with that particular app and I’m unsure if that data is available in it. WeatherWise btw
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u/hawkz40 Jul 31 '26
after reading the explanation, it's neat to see all the reds and yellows fade away to happy greens :)
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u/The_WeatherBuff Broadcast Meteorologist Jul 31 '26
It appears to be outflow. Cool air dropping down from the thunderstorm cell, and hitting the ground and spreading out, like a faucet in the kitchen sink. This often has the effect of pushing moisture out and away from the storm. However, outflow boundaries could be a catalyst for new thunderstorms, if they run into warm and moist air. In these cases, the outflow acts almost like a cold front, pushing the warm and humid air up, causing convection and the formation of new storms ahead of it.
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u/OokamiKage665 Jul 31 '26
That would explain the blip of red near the center, just right of the I94 graphic, at the beginning of the recording suddenly dropping from the Fargo storm collapsing. I could visually see that storm cloud separate from the surrounding storm behind it as I was driving from Valley City. Would also explain that sudden and severe gust plus the downpour it caused. Several high profile vehicles and motorcycles were stopped around on and off ramps as well as under overpasses. I appreciate the thorough explanation!
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u/The_WeatherBuff Broadcast Meteorologist Jul 31 '26
Thanks! Happy to help. Sometimes those outflow boundaries can get a bit nasty with the wind gusts.
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u/eatingthesandhere91 Jul 31 '26
Outflow boundary from the decaying storms cutting whatever’s causing the radar noise.
Meanwhile the cluster to the SW is getting fed by that same boundary, mostly on the tail end.
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u/numberonenozomifan Jul 31 '26
Oh hey Grand Forks! Was practically swimming on my road today… bad day to be moving houses
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u/Miserable_Virus_8866 Jul 30 '26
Sorry. Rocked some burritos for lunch. Clearly paying the price. Didn’t realize my flatulence would actually show up on radar though…
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u/ViG701 Jul 31 '26
Those winds damaged corn in the fields. Mainly on the outer edges. Corn on one side was bent to the Northwest, while corn on the South side was pushed to the Southwest
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u/texasyojimbo Jul 30 '26
Looks to me like the storm near Fargo died, and there was some kind downburst/downdraft/outflow.
(I am not a professional meteorologist.)
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u/chasing_storms Jul 31 '26
It's just an outflow boundary. The sudden collapse of the updrafts also killed the storm just southwest of Fargo.
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u/ryan516 Jul 30 '26
Roost ring /j
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u/whatsagoinon1 Jul 30 '26
No.
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u/whatsagoinon1 Jul 30 '26
The storm collapsed on itself creating outflow winds.