Meteorology and atmospheric science at Penn State.

This is weather world.

Good evening and welcome into Weather World.

On this Thursday, August 21st, 2025.

I'm Christian Spallone joined alongside Karl Schneider tonight.

And Karl, it's been persistently really cloudy and cool for much of this week, but maybe some changes on the way.

Yeah, Christian, the clouds hanging on and at least the short range forecast overnight tonight.

But they'll begin to clear and we'll have plenty of sunshine tomorrow.

That's good to hear.

We'll get more details from Karl on that forecast in just a few moments.

Also on the show tonight, we will have a series of Throwback Thursday features from back in the 1980s that focused on heat.

But first, here's Karl.

Thanks very much, Christian.

And I feel like we've been saying that the clouds are going to clear and they really haven't as fast as we would have expected or hoped, but I believe that's actually going to happen tonight and it's going to lead into a very sunny tomorrow.

But we'll start with a look at the four cam across the Commonwealth that shows a lot of cloud cover.

It was hard to find blue skies.

Skies briefly cleared in southwestern PA.

But I think clearing is going to be the theme tonight.

And by tomorrow most of us will be enjoying sunshine.

We can see the radar and satellite this afternoon, showing a bit of clearing starting to occur in northeastern PA.

I think things are going to clear from northeast to southwest.

We've also had a few breaks in the clouds in southwestern PA. That's just kind of a sign of what's going to occur tonight.

And after these clouds clear, will be faced with some clearing skies and falling temperatures, likely into the 50s in many areas.

But right now, temperatures.

It's been a struggle this afternoon, but most of us have gotten to at least 70 or a few degrees above that, still in the upper 60s in parts of northern PA and some upper 70s along the I-79 corridor, which I think is going to be more typical of what we're going to be seeing for daytime highs over the next couple of days in the dew point.

Dew points have been in the low to mid 60s, so not muggy, but given how low the air temperatures were, there's a very small difference between the dew points and the air temperatures, making the relative humidity quite high.

So the air feels a little bit moist.

I think that's going to change tomorrow as dew points fall and temperatures rise, increasing that difference.

Broader view with the radar and satellite shows up to our northeast.

That's where the air mass for tonight is coming from.

And skies are clear there.

So some drier and clearer conditions moving in here over the next 12 hours or so.

A broader view shows Hurricane Aaron off to the east.

That's going to be a fish storm and not an issue in our short range forecast.

But our next weather system that's going to impact us not until Saturday night is across the upper Midwest.

So in between, high pressure is going to be the name of the game here over the next 24 to 36 hours or so.

The temperature map this afternoon shows some cooler air across the northeast, thanks to a lot of that cloud cover.

Really.

Absence of big what I'd consider big time heat in the southern Plains, but some hotter conditions are are taking place just ahead of that cold front.

So I think temperatures are going to increase, especially by the time we get to Saturday as that cold front starts to approach our area.

So the evening surface map shows high pressure off to the west that will start to drift to our to our area overnight tonight.

Clouds as I said, will be decreasing overnight tonight.

And as they decrease in the temperatures decrease as well.

Um, we could have the development of some fog, particularly in north central PA and south central PA, along the ridges and valleys as well.

Then moving into Friday, looks like high pressure is going to be right smack dab overhead.

So not much in the way of cloud cover by the afternoon hours.

Not much in the way of wind either, and dew points remaining at comfortable levels, likely in the 50s.

Then we'll have to watch this next cold front as it makes an approach.

This will be on Saturday.

I think eastern PA is still decent on Saturday with plenty of sunshine.

Western PA on Saturday.

That's when the clouds start to bubble up, especially in the afternoon, and then we'll have the risk of some showers and thunderstorms in the afternoon hours as well.

I think coverage is scattered so most folks will stay dry through most of Saturday, but it's something to be aware of, especially as we go later in the day.

So tonight the clouds begin to clear.

I think most of the clearing will occur first in northeastern PA, then moving towards the southwest where clouds could hang on a little bit there.

Towards daybreak as the clouds clear, that will allow temperatures to fall into the 50s, and we'll have to watch the potential for some dense fog to develop late tonight, especially in north central PA and some of those valleys in the Ridge and Valley region.

Then moving into Friday, I think it's going to be mostly sunny for all of us.

Clouds can hang on a little bit in southwestern PA in the morning hours, but I don't think that will be a theme throughout the entire day.

Lots of sun highs on either side of 80.

Not humid and not much in the way of wind either.

A very comfortable Friday, and I think that will still be the case in eastern PA on Saturday.

Will where things will be fairly comfortable, but in the west the clouds begin to increase, especially in the afternoon hours, and we'll introduce the chance of some scattered showers and thunderstorms as the cold front starts to approach.

We're back in a moment with more.

This looks like a pretty good spot for a break, and it has been a hot day out here, pounding the pavement in search of still some more weather wise Pennsylvanians.

How about a nice picnic?

Brunch?

Sounds great to me.

You know, Fred, it's so hot out here.

I bet you we could actually fry an egg on the pavement.

Fried eggs for a picnic, a perfect idea.

Well, let's see what we have in the basket.

You know, there's nothing quite like the fun of a picnic.

You're right.

Fred, the Pam, please.

There you go.

Also, we have a salt and pepper.

And of course, the egg.

I think we're all ready.

Would you do the honors, sir?

Gladly.

You know, not only is this a great idea for a picnic, it's a great idea for a question.

Have you ever heard that it's hot enough to fry an egg on the pavement?

Do you think that's true?

Sure, I've seen it.

I've tried it.

It didn't work.

Do you think it's ever hot enough to fry an egg on the pavement?

Well, my brother fries dance with, um, with with that hot on the pavement all the time.

I mean, with the, um, magnifying glass.

He fries ants, you know, but I think that you could probably, um, cook a relatively nice cut of meat.

Oh, I've done it.

You've done it.

Just just just to find out if it's true.

Go out in the hood and smash it on the hood of a car.

Watch.

It'll cook.

Okay, I'm gonna try that.

Don't do it unless you put some stuff on it.

Because you're hard to get off.

Maybe out in California.

Yeah.

For example, in Kuwait or in Texas.

Uh, but it can be done in Egypt, not in Sullivan County.

We're naturally air conditioned.

Sound like the Chamber of Commerce?

Oh, yeah.

Well, that's what I am.

Wherever you may try to fry an egg on a sultry summer day, it really comes down to a matter of albedo.

Albedo is a term to describe how well a surface reflects the sun's energy from out in space.

The albedo of planet Earth is about 35%, meaning that a little over a third of the sunlight is reflected back to space.

A new covering of snow or ice can reflect over a 95% of the sun's energy, while the lush fields and farmlands of Pennsylvania, being much darker in color, will only send back 20% of the sunlight.

A recently paved asphalt parking lot has an albedo of less than 3%, so it absorbs 97% of the sun's heat.

And on a truly hot day, that's just the place to try and fry an egg.

Looks to me like our pavement picnic is an utter failure.

Fred, you're right.

You know, we picked the hottest day in central Pennsylvania.

We picked the darkest asphalt.

The egg's been there for ten minutes, and it still hasn't fried.

I'm still hungry.

Do you have any breakfast cereal in that basket?

Uh.

Let's see.

Well, how about oatmeal?

If you look around you, there's little doubt that summertime is here.

The trees are in full leaf.

The grass is lush and green, and flowers dot much of the landscape.

And yet, just a few yards from me, winter's icy grip still lives.

That's right.

The remnants of this past winter's bone chilling, frigid air are just a matter of steps away.

You might ask, what's the solution to this mystery about winter and mid-summer?

Well, it's an ice mine in Huntington County.

This is snow in the middle of summertime in Trough Creek State Park.

And as for how this ice mine came to be, park Ranger Dave Hillegas explains, the ice mine was originally a mining shaft dug back in the early 1800s by the ironworkers that worked here at this area at Peerless Furnace, and they were searching for iron ore, and they dug the shaft in hopes of finding good quality iron ore.

They didn't find the quality they were looking for.

So the shaft was abandoned and just more or less left set.

Now in the 1930s, when the C.c.c.

camps came into this area, they organized this as a state park, and when they were developing the area, they came across this hole here and they found that it was full of ice, and they thought it would be a good idea to dress it up a little bit and make it available to the public, so that people could see this natural phenomenon that occurs here.

And while it may be a natural occurrence, it is certainly extraordinary to find snow and ice at this time of the year anywhere in Pennsylvania.

However, the best time to visit is a bit earlier in the season.

Generally, the ice is thickest in early April into about the middle of May.

It takes that long for the rock mass to begin to warm up.

Once it begins to warm up, of course the ice mass shrinks back down very rapidly.

Well, the reason the ice forms in the mine as it does, is behind me.

Here you have all this rock mass.

Now, the topsoil here is very thin, even though we do have some trees and so forth growing here.

And most of the blocks of the rock below are broken into segments.

And what happens is, over the winter months, the rock mass cools.

And when it reaches a temperature which is below freezing as the core air exits in the summertime, it meets the warmer air of the spring and summer, which is more moist and causes the ice to form in the mine.

Most caves and mines do stay cool through the summer, but the temperature change in this abandoned shaft is a dramatic drop even on a chilly July day.

Temperature change is, uh, anywhere from probably 30 to 5060 degrees, depending upon the outside air temperature.

Of course, if it's 80 degrees in the summertime, you're still having freezing temperatures exiting out of the mine.

Obviously, you wouldn't have the ice formation there.

So you're looking at, uh, anywhere from maybe 40, 50, even 60 degrees temperature variation from the outside air temperature to what's coming out of the shaft itself.

So when the sultry days of summer get you down, take comfort that winter hasn't left.

It's simply gone underground.

Well, the clouds are finally going to be on the way out overnight tonight, leading to a mostly clear sky beginning in the northeast.

Clouds will clear from around northeast to southwest through the night.

Um, we'll have to watch for the potential for some dense fog to develop in parts of North, central and the central valleys of PA. Late tonight as the clouds clear and we have some wet ground allowing that fog formation to be, uh, an issue elsewhere.

Lows largely in the 50s.

Then heading into Friday should be a pretty nice day.

Mostly sunny and comfortable.

Lots of sun.

Highs either side of 80.

Not much wind either.

Things start to change though as we go into Saturday becoming unsettled in Western PA.

The clouds will increase there throughout the day in eastern PA though.

Mostly sunny day with highs in the lower 80s.

And Christian um, I don't know.

There's not a whole lot other to say than really just try to get out and enjoy tomorrow.

It's going to be pretty decent weather for moving here at Penn State.

There's a lot of folks arriving into town, so certainly could be worse.

Yeah, definitely not a bad afternoon for some of that and great for some outdoor activities as we wrap up the workweek.

Carl.

So thank you for your forecast.

And make sure to come back and join us on Weather World tomorrow night for our Friday forecast frenzy, including the weekend forecast as well as the extended and week two trends.