Category Archives: Weather

Top o’ the mornin’

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I took this picture Monday morning when I walked the dogs up to the top of the mountain. It was about 9:30, long after sunrise. Just right of center, where the steam plumes are, you can see the remains of the temperature inversion from the calm, clear atmosphere we had over Sunday night.

topothemornin

The foggy, linear stream on the left side of the plumes is the top of the inversion. If we had walked right after sunrise, the top of the inversion would probably have been more obvious, but it was already dissipating by this time. It would, however, have been at approximately the same level in the atmosphere.

An inversion serves as a cap on the atmosphere close to the surface. It traps moisture or pollutants that are beneath the top of the inversion. The temperature normally decreases as you go up higher in the troposphere. Air that is warmer than the air at the surface (like smoke from a brush fire) will tend to rise through the troposphere because it is lighter than its surroundings. In an inversion, the air actually gets warmer is you go up, so things like smoke will rise for a while, but will tend to stop at a low altitude. A very hot plume can push through the inversion and then continue to rise. The steam plumes are doing that.*

The steam plumes are coming from a paper mill. The two tall stacks to the right of the steam plumes are an old and a new stack at Plant Hammond, one of the two Georgia Power coal-fired power generating plants we can see from Lavender Mountain.

Plant Hammond’s active stack is 675 feet (205.8 m) tall. Although nowhere near the tallest stack in the world, it is tall enough to be on the Wikipedia list of the tallest stacks in the world.

It’s tall for a reason – the Clean Air Act, which goes back more than 50 years. That act has provisions that limit the concentration of pollutants at ground level. One might think that the logical way to do that would be to limit the emission of pollutants, but it happens that if you introduce the pollutants high enough in the air, they will have been diluted enough that by the time they can reach the ground, they will meet the standards. So the Georgia Power stacks are high enough to push emissions above the top of any reasonably probable inversion height. If the stacks were below the top of the inversion, their emissions might reach the ground because they might be trapped by a particularly strong inversion, or they might just reach the ground because of other atmospheric conditions. When the emissions are injected into the atmosphere high enough, they will be diluted enough to meet the letter of the law.

Rome happens to be in a nonattainment area for atmospheric particulate matter. That status somewhat limits the industrial development of this area. Our local newspaper, the Rome News-Tribune, does not like that. They have published editorials mocking the nonattainment status (like saying that our air seems clear enough to them).

To cast doubt on the legitimacy of the measurements that caused the nonattainment status, the editorial writer has pointed out that the air quality monitoring station is located near the base of the Plant Hammond stack. The implication seems to be that only an idiot would measure air quality that close to a pollution source, and thus the measurement must not be representative of Rome’s true air quality. I have written letters to them in the past pointing out that if you want to avoid measuring the emissions from a tall stack, the best place to put your instrumentation is at the very bottom of the stack. That is perhaps not intuitively obvious, but it is nevertheless true. However, the truth seems not to be a persuasive argument when it comes to commercial development and newspaper editorialists. (I might have mentioned this in an earlier post.)

You might be wondering why the top of the inversion is so much lower than the top of the mountain, where I have mentioned on several occasions that we are warmer than the surrounding lowlands because of a temperature inversion. The reason is that although the top of Lavender Mountain is above the actual inversion, the conditions that cause the inversion also work on the atmosphere up here. As the air on the mountaintop cools, it flows downhill into the lower areas, reinforcing the inversion down there. That air is replaced up here by the surrounding air, which is warmer than the air that flows down the mountain. I have mentioned before that we can be as much as 10 degrees F warmer than the air at the bottom of the mountain.

Oh, and Happy St. Patrick’s Day.

* The tropopause acts like the top of a temperature inversion. The air temperature gets lower as you go up in altitude until it reaches the tropopause. In the stratosphere, which is the layer above the troposphere, the air gets warmer as you go up. That’s why thunderstorms form anvil tops when they get to the tropopause. The clouds hit the warmer air and their buoyancy can’t get them any higher. At that point they tend to spread out sideways, forming the anvil top. Occasionally a very strong thunderstorm can push its clouds through the tropopause, but not very much higher.

Changing weather

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Wednesday we had the warmest day so far this year, but there’s a cold front on the way. The front is moving from the west, but after a short shower, the eastern sky gave a hint of change to come.

rainbow_4mar15

There was a complete rainbow, but I couldn’t get the entire bow in the frame. The other side was behind some trees, so it was hard to see anyway. There was still a little of it left when I took the dogs out later.

sky_4mar15

Despite our high up here of around 67 on Wednesday, we are under a winter weather advisory for Thursday. We are at the southern edge of the advisory area, so I doubt that we will see much frozen precipitation.

Snow days

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We had a nice snowfall Wednesday evening and night. We had seven inches by the time it stopped.

deck table snow

Chloe apparently has some insulation on her rear end.

chloe snow walkI like it when it snows here. We get snow so infrequently that it doesn’t really get too inconvenient. That makes it possible to appreciate the beauty. It also opens a new world where the passage of wild animals is no longer secret. I took Zeke for a short walk Wednesday afternoon when there was less than an inch of snow on the ground. Here’s what I think is a set of rabbit tracks.

rabbit tracks

These are what I know for sure are fox tracks, because I saw the fox dart across the road.

fox tracksThe tracks led straight up the driveway into our new property.

Thursday morning I took Zeke out again; I left Lucy at home because her belly would have dragged in the snow the whole way. There was a fox set of tracks that started at the point where Fouche Gap Road crosses the top of the mountain. We followed them most of the way down to the bottom of the mountain. The tracks stayed mostly in the half-buried tracks left by a truck late Wednesday afternoon. Occasionally they took off up the slope of the road cut, and then turned around and came back down to the road.

snow tracks

The zigzag tracks are Zeke’s. I’m not sure whether another animal joined the fox occasionally.

It’s hard to capture what the eye sees because our visual system is so good at image processing. I tried to get a hint of it with this panorama.

snow panorama

There was significant melting Thursday, but there was a lot of slush and water left on the road that refroze, so it was tricky to walk on it Friday morning. I took both dogs, but turned around after a short distance. I think the rough ice was too much for Lucy’s delicate, little feet. It should be all clear by Saturday morning, despite another hard freeze Friday night.

Cool cats and wind chill

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It has been cold here for the last couple of days. We have been stoking up the wood stove, but with the strong wind, the house cools off enough at night that by morning the heat usually comes on.

A new stray dog has been roaming around, eating cat food and keeping a good distance between any himself and any human. We put a plastic dog house out for him (her?) but he’s too skittish to get into it. We have started putting dog food out, hoping he will stop eating the cat food. Instead, of course, he eats the dog food and then the cat food. We have been worried about the dog staying out overnight in this weather, but he seems to have survived the coldest night so far.

The cats seem to have found their places. This is where Leah has set up a nice cat den under the stoop in the garage.

sly under the stoof

Sylvester slept here sometimes before it got so cold. Now he comes inside. So do Chloe and Smokey.

We put a two-story cat house in the driveway with a nice covered porch and a lot of cedar shavings. Some cat or cats have been sleeping there, but Leah was afraid it was too cold, so we put a cat house made from a cardboard box in the garage. Leah put a comforter in it, and Rusty often can be found there. Dusty occasionally lies in it, too.

dusty and rusty boxed

I had to take this picture from a distance to avoid spooking the cats, so the flash didn’t do much to light them. That tail end is Dusty’s. The front end is Rusty’s.

For the really cold weather – Wednesday night it went down to 10F (about -12C) — we got a heated pet pad for the box. It doesn’t really feel warm to the touch, but it’s supposed to heat up to a cat-friendly temperature as they lie on it. Rusty has been in there, but Dusty, unfortunately, seems not to use it. We aren’t sure where he sleeps. We suspect he’s spending time in our driveway culvert, but we hope not. We also suspect that Sylvester and Smokey chase him out of the garage, and sometimes even away from a nice spot in the sun.

Lucy and Zeke have coats, but Thursday morning I cut our walk short because with the wind it was just too cold. Friday, even though it was a few degrees warmer, I left Lucy at home. It was about 19F (about -7F), but with only light wind, it was bearable for Zeke and me.

Which brings me to the wind chill factor. Wind chill factor seems to have been designed especially to let TV weathermen spread panic. OK, that might be extreme. They only try to enhance the public’s perception of the severity of the risk of cold weather.

The idea of a wind chill temperature has been around for more than 70 years, and it has been criticized for various reasons for about as long as it has existed. I personally don’t like wind chill or its warm-weather opposite, the heat index, or the “feels like temperature.” The biggest criticism of wind chill has been that it overstates the coldness. I think in some circumstances it does the opposite. For example, I have been outside while visiting friends in Colorado on a clear, still night when the temperature was -5F (about -20C) and it did not seem extraordinarily cold. I was not prepared to strip to my skivvies and snow ski, but it was not unreasonable to spend some time outside. On the other hand, I have been outside when the temperature was near 15F (about -9C) with a strong wind (15F with 30 mph wind gives a -5F wind chill), and it was nearly unbearable.

I think the heat index temperature is even less realistic. If the temperature is 90F (32C) with a relative humidity of 65%, the heat index is 103 (expressed as a Fahrenheit temperature). I have suggested that a test of that is to pick such a day and sit outside while you turn your house thermostat to 103 and give your house a chance to warm up. Then go inside and see whether it feels the same as outside.

I’m sure there are benefits to telling people that weather conditions may be so extreme as to pose some potential danger if you’re not prepared. But the biggest benefit seems to be to the TV weather forecaster.

It was snowing as I wrote this earlier Friday evening. After dinner, Leah and I drove down the mountain to eat and go to the grocery store. There was about a quarter to a half an inch of snow on the road. That doesn’t sound like much, but when it’s melted and refrozen, it turns into a thin layer of ice. That was enough that one car was in a ditch about seven miles from home, and we had to stop going up the mountain to let someone turn around to go back down. We had no trouble. Just a couple of days ago we traded our front-wheel-drive Volkswagen for an all-wheel-drive Subaru. Just what I wanted it for.

Heads in the clouds

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It has been rainy and cool here for what seems like weeks. Saturday was a dreary day. When the drizzle stopped, the fog moved in.

foggy road

This was taken at the intersection of Lavender Trail and Fouche Gap Road, looking up towards where the driveway enters our new lot. The official visibility in Rome was 10 miles, which is essentially unlimited. The visibility up here on the mountain was not much more than 100 yards; we were actually up in the clouds.

It has rained so much and we have had so little sunlight even when it’s not raining that the ground remains saturated. Neighbor John’s bulldozer has sat on our lot since the work he did more than two weeks ago. The ground is way too muddy for clearing.

foggy bulldozer

You can just see John’s bulldozer about a stone’s throw from where I took the picture.

The temperature rose through the night Friday, and it’s supposed to continue to rise this night, Saturday. A squall line is supposed to move through the area sometime around midnight. After this round of rain, the temperature is predicted to drop. The predicted high on next Thursday is 28 F. There is sun in the forecast for at least a week, so maybe John can start clearing again before too long.