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ballsonthewall t1_j5t9xz2 wrote

Hi, since everyone else's comments are conjecture...

We are in a dry slot. Low pressure systems are often pulling in warm, moist air from the south and cool, dry air from the north as they develop and rotate. Pittsburgh is in a bad spot because often times the mountain ridges to our east will help facilitate pockets of air that is either too dry or too warm for snow.

I can't attach a picture, so here's a link with a nice illustration of a dry slot

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yourfavoriteyinzer t1_j5tb76r wrote

Here's my risky click of the day, wish me luck 🤞

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ballsonthewall t1_j5tbbpe wrote

lmfao on any other day I wouldn't trust me, but when it comes to the weather I'm too big of a nerd to be anything but a straight shooter lol

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zipcad t1_j5tbm84 wrote

the slot, how’s the slot?

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blp9 t1_j5tu1b1 wrote

The other part, as illuminated for me today, is that part of this is a radar artifact. The center of the "hole" is actually the radar site out in Moon, and as the precipitation dropped closer to the ground, the hole more or less closed around Moon (with lots of variations based on elevation).

This is because the radar shoots up at an angle, so the further from the site you are, the higher in the atmosphere the returns are happening.

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capchaos t1_j5uhvad wrote

Joe is no longer around to say it would. He lived in Moon Twp BTW.

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Eco-freako t1_j5tfjqq wrote

This is in addition to what u/ballsonthewall said: It probably also has some to do with the urban heat island effect, which is more severe is summer, but still impacts weather in the winter. Basically, we have a city of concrete buildings that, during the winter, are being heated and emitting some heat out into the environment which creates an overall warmer local atmosphere than the surrounding area.

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ballsonthewall t1_j5tgllr wrote

urban heat island wouldn't really have much impact until the snow is below radar levels anyways. snow might stick less downtown or vary slightly with elevation, but most of the dynamic weather is happening far enough up in the atmosphere to render small changes in what precip looks like at the surface moot.

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vivamario t1_j5twa79 wrote

So is some of that southern moist air is smashing into the ridges in central PA? Is this why I have to prepare like I'm going on a trek to Siberia to make the 2-hr drive over the mountains to Penn State in the winter?

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emeraldjalapeno t1_j5tefg3 wrote

Interesting, I thought a dry slot was more in the southwest and legit meant dry. Where you'd have rain come from the Pacific and then just not hit a city/town for whatever reason. I've lived in a couple of places where that's happened but Pittsburgh gets rain. I'm no expert, just what I thought

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ballsonthewall t1_j5tepbt wrote

winter storms are insanely intricate and complicated, this thing dropped a foot of snow in Oklahoma and tornadoes in Texas at the same time yesterday. It's really cool to learn about them, but once you start, it's easy to understand why they're so hard to forecast... particularly here.

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Stickel t1_j5uo3kw wrote

Somerset mountain be huge though! Pretty much goes along with this too, it's insane when I travel to da Burgh and the big weather difference on each side of that tunnel, I come from Bedford on a half decent regularity to visit friends and the night life! But it always amazes me, I remember the one Halloween it was in the 60s here but in the 40s there thankfully for me because I was in a full care bear suit... it helped keep me cool

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alakazampowdickmow t1_j5tfvjv wrote

Do the rivers converging have anything to do with this as well?

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ballsonthewall t1_j5tgufi wrote

not really. what most people don't think of is that weather is 3D, rather than a plot of rain and snow on a 2D map. layers of warmer and colder air in the upper atmosphere are far more pertinent to what precip you see at ground level than anything happening on the surface. that's not to say small variations caused by local microclimates don't make a difference in observable weather, rather that they aren't going to change the whole metro area's weather like this dry slot did.

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alakazampowdickmow t1_j5tuu22 wrote

That makes sense. Like you put it I never really gave the 3d model a thought, especially with the different layers of air currents and hot and cold zones.

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TiesThrei t1_j5unieo wrote

This is true, also part of it is we're just at a much lower elevation than many of our surrounding areas. I've driven from a foot of snow in the hills around Somerset back to no snow here before.

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