Just Ask John

John Gumm — Fri, 02 Nov 2007 19:41:00 GMT

Under Pressure

Ruth from Winchester asks:

I'd like to know how barometric pressure readings are determined to be high or low. And isn't this somewhat different for each region? What is high or low for this area? It seems that sometimes 28 point something is high and other times it's 'stationary' or something. What's the average, what's the difference, and what does it mean in terms of every day living?

Ruth,

The record high pressure was 30.93 inches for Cincinnati and was set on 1/18/1921. When you see record high pressures like this, the air is heavy and cold. High pressures like this usually occur during our most brutal arctic outbreaks and typically are associated with dry, calm conditions and sunny skies. The highest barometric pressure recorded in the U.S. was 31.85 inches back in January 1989 in Northway, Alaska. The highest barometric pressure ever recorded on Earth was 32.01 inches in Agata, U.S.S.R., on December 31, 1968. Agata is in Siberia. It was clear and frigid at the time, with temperatures between -40° and -58° F! Notice these tend to occur in the winter? That's when the air is the coldest (and heaviest) and all that heavy air is pushing down on us.

On the other hand, the lowest pressure ever recorded in Cincinnati was 28.81 inches on 1/26/1978. Low pressures typically accompany stormy weather and that was the case back in '78. Anyone remember the blizzard? That pressure reading was taken during that storm! The lowest air pressure recorded in the U.S. happened during the infamous 1935 Florida Keys hurricane. The pressure got down to 26.35 inches! The lowest pressure on Earth ever measured was 25.69 inches on Oct. 12, 1979 in Typhoon Tip in the western Pacific Ocean. As you can see, these low pressures occur in storms. The lowest of which occur in hurricanes and typhoons.

The average air pressure is 29.92 inches. So anything above that could be considered "high" and anything below that could be considered "low". Changes in pressure can signify big changes with the weather and many people are sensitive to these changes. That must be why so many people love San Diego, CA. It experiences the least amount of pressure changes of anyplace in the U.S. St. Paul, Alaska and Charleston, SC experience the most pressure changes.

John

Strange Fog

Amy from Ft. Mitchell writes:

Hi. Don't know if you can help me or not. Last evening I was camping near Warsaw, Kentucky. Around 10:00 pm I looked into the sky and saw what I'd desribe as a rainbow sort fog, almost resembling a trail left by an airplane. It was a crystal clear sky and all the stars were visible. This "trail" that we saw was lower than the stars. Within an hour it had not disipated but had moved behind us just as the moon had. What was it that we could have seen? We finally came to the conclusion that it had to be some type of gas vapor. We had no cameras except for one on a phone and the picture did not turn out. Didn't know if you know what it could have been or if it was some type of eclipse. I'd love to find out what it was that we were seeing. Hope you can help. Thanks so much!

Amy,

Without seeing it, I can't say for sure. But I suspect your initial thought was right. It sounds like a contrail left by a jet. Since these are so high in the sky, they can reflect sunlight back down to your eyes long after the sun has dipped below the horizon. Other atmospheric optical effects can also make these appear different colors or even look like "glowing gas".

John

The Color of Clouds

Jaclyn from Union writes:

Why are rain clouds darker than normal, every-day clouds we see in the sky?

The main reason for this is because the rain actually soaks up sunlight! When clouds are white, they usually consist mainly of ice crystals which reflect back all wavelengths of light (all the colors). All the colors added up together create white. So if you see a cloud that is more whitish, it likely contains mainly ice crystals. However, clouds that contain rain may actually appear gray or a blue-gray color because the water in the clouds tends to "soak" up the other wavelengths of light. So with rain clouds, they appear a darker color because sunlight can't get through them. The color of the cloud will also vary depending on the angle you're looking at it and the angle of the sun in relation to you and the cloud.

The Green Flash

Christopher from Mason writes:

Now and then in the early morning I will see on the horizon big flashes of green light. Is this weather related?

Christopher,

This is an atmospheric optical phenomenon known as a "green flash". It is produced when sunlight travels through the atmosphere and is bent. In this case, most of the bent wavelengths (colors) of sunlight are blocked by the horizon, except for the green. For a more technical explanation, check out this excellent page:

John

To Ditch or Not?

Brandy from Laurel, IN writes:

Growing up I had a huge thing for weather, its one thing I wish to this day I went to college for, but anyway my question is about tornado, yeah I know not really the time of year for it, but I have always heard to lay down in a ditch when one is coming. What I find so odd is all these real tornado videos I have seen shows a tornado traveling right down the ditch itself! How is that any type of protection? I know you aren’t suppose to hide under an overpass, but it seems as though you would have a fighting chance there as to being out in a ditch waiting to be sucked up. Thank you for reading!

Brandy, the bottom line is, there is no good place to stay safe from a tornado except in a sturdy, well-built building! Mobile homes are horrible places to be during a tornado. Cars are just as bad. As far as the overpass, experts advise to stay away from those as well. The reason? Well, while the overpass may provide some shelter from flying debris, it actually may funnel the winds and make them stronger! That would make it nearly impossible to hang on and increase your risk of getting sucked up. You may have seen some video from several years ago of people taking shelter under an overpass from a tornado. The winds got bad and they held on and were OK. However, that tornado was weak and didn't even hit them directly. If it would have hit them directly or would have been stronger, they likely wouldn't have made it.

Now, for the ditch. The thought here is the debris would fly over your head. In some cases, it might work. But studies have also shown most debris collects in ditches during a tornado. This would be a "shelter" of last resort. Better than a mobile home or car, but not as good as a strong building. Some have tried to outrun tornadoes in cars and sometimes it works. Other times, people get killed. It's advised you don't do this.

My advice: keep up with the weather when severe storms are expected and make sure a sturdy building is available. It's the only good shelter.

2007 Goes Down as Dry

Joshua from Cincinnati writes:

In Mid November we were below the rain level for the year. We had a lot of rain in December. What was our water level by the end of 2007?

Joshua,

Despite all the rain toward the end of the year, it was not enough to make up the rainfall deficit that really increased over the summer months. We finished 2007 with 36.72 inches of precipitation which is 5.88 inches below our average of 42.60 inches. The final 3 months of the year saw above average rainfall, helping that deficit out a bit.

John

Seven Feet of Snow

Nancy from Cincinnati asks:

How much snow would we need to get, by the end of the year, to make up for the lack of rain?

Nancy,

While the big rains a few weeks ago helped, as of today, we're still 8.52 inches of rain below our yearly average. Assuming a standard 10 to 1 snow to water ratio, we'd be talking about 85.2 inches of snow, which is about 7.1 feet! That's a foot taller than I am. Assuming a dry, powdery snow at a 15 to 1 ratio (which forms in colder air), that's 127.8 inches, or 10.65 feet. Let's hope Mother Nature doesn't "even things out" too quickly this winter!

Ring Around the Moon

April from Sunman, IN asks:

Hello, On the early morning of Wednesday, October 3 2007, @ 6:45 a.m., my son & daughter came in from feeding the goats & told me to come out and look at the moon. There was a big ring about 2 inches from it. It was like a foggy haze that encircled the moon. It was quite a site. I’m sure it has something to do with the weather. What was this called, and why does it occur. Thanks for your time in advance.

Hey April! Believe it or not, it’s just called a “moon ring.” This tends to happen several times per year and you’d be amazed at the number of calls we get about it. In fact, I remember one summer when I was growing up on the eastern side of Cincinnati my grandfather and I saw one of these rings. I asked him what it was and he had no clue. He called Ira Joe Fisher and asked him about it. That was the first ever explanation I heard about the “ring around the moon”!

Anyway, here’s how it works: We tend to get these rings around the moon when cirrus clouds are present and when the moon is high in the sky. Cirrus clouds are made up of tiny ice crystals about 20,000 to 30,000 feet above the ground or higher. These ice crystals tend to have six sides (hexagonal). As moonlight passes through these ice crystals, the light gets bent (or refracted as we scientists call it) at a particular angle (22 degrees usually), focusing the light in a circle or ring around the moon. Sometimes you can get multiple types of ice crystals in the clouds which will refract the light at different angles (usually 46 degrees). In these situations, you may even see two rings around the moon…one small and one large!

There’s an old wife’s tale that says “ring around the moon, rain or snow soon.” And in some cases this is correct. You see, these high, thin cirrus clouds can sometimes precede warm fronts. As a warm front approaches, the warmer, more moist air first arrives aloft creating these thin cirrus clouds. Of course a warm front can help to create rain or snow and usually precedes an area of low pressure and cold front which can also produce rain and snow.

Anyway, I hope this helps!

If you would like to send me a weather question, email justaskjohn@local12.com or just visit this link: http://www.local12.com/content/weather/justaskjohn_mail.aspx.Cincinnati weather for the past 100 years or so....

Will from Colerain Township Asks:

My name is Will and I'm a Captain with the Colerain Township Fire Department. The department is currently assessing it's risk/hazard data and we are in need of a climate description for our area. I found several on line for Indiana and West Virginia, but none for the Greater Cincinnati/Southeast Ohio region. Any thoughts on where I could locate such information?

Thanks for all of your help.

Will, this information may be hard to find on the internet, but it is out there. First, let's define climate. Put simply, climate is just the weather averaged over some defined period of time. There is a set way to describe climates all across the world which was developed by a German Climatologist back in 1900. His name was Wladimir Köppen and he decided that plants native to certain regions were the best indicator of climate type. His system took into account average annual temperatures and precipitation, and the seasonably of that precipitation. His system splits things up into five main groups with different types and subtypes. I won't get into all them here, but if you want further reading on the matter, check out Wikipedia's page: http://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification

For our area, we fall right smack dab in the middle of two climate types. Most texts put the Cincinnati area under the classification of a "humid continental climate" which is described as a “zone of conflict” between polar and tropical airmasses. In the U.S., this region encompasses much of the Midwestern and eastern parts of the country. This climate tends to have variable weather patterns and large changes in temperature throughout the seasons. To further define our climate, we can put ourselves under another subtype called the “Hot Summer Subtype” which is characterized by hot rainy summers and snowy winters.

However, since we are pretty much right on the line between two different climate types, some have also argued we are in the “Humid Subtropical Climate” as well. This is a climate that tends to have hot, humid summers and chilly to mild winters. Of course, we would tend to be in with the colder variety of this climate type.

It’s my opinion that we fall mainly under the “humid continental climate” along and north of the Ohio River, with areas to the south of Cincinnati falling into that “Humid Subtropical Climate” classification.

Anyway, I hope this helps!

If you would like to send me a weather question, email justaskjohn@local12.com or just visit this link: http://www.local12.com/content/weather/justaskjohn_mail.aspx.

What a summer to be pregnant!

Annette from Dillsboro, IN asks:

Would you tell me one last time, how many days during the summer and early fall of 2007, reached or exceeded 90 degrees? I lost track at 46. Thank you very much!

And on a related question, Amy from Lebanon asks:

I will be delivering a baby in a couple of weeks. I'd like to know (for the baby book) how many days we have had in 2007 in the 80's and how many in the 90's. What a summer to be pregnant!!!

Thanks!

Thanks for the question Annette. And Amy, I certainly feel for you! When my wife was pregnant with our first son, we were living down in New Orleans. She was miserable. This time around, she’s looking forward to being pregnant during a cold Tri-State winter instead!

At any rate, here’s the lowdown, or the "highdown" as the case may be:

In 2007, we experienced 54 days of 90 degree-plus weather. This put us in a tie for 4th place all time for 90 degree plus days with the year 1934. The record was back in 1936 when we hit 90+ 64 times, followed by 1944 (58), and 1913 (56). Out of those days, we saw the mercury reach 100 degrees plus on 5 days (August 8, 16, 22, 23, and 24th). Keep in mind, temperature readings in most of those years back then were kept downtown amongst all the buildings, concrete and blacktop which leads to hotter conditions. Today the readings are kept out at the airport in Hebron, KY which will run a bit cooler on hot summer afternoons. That alone puts into perspective on just how hot it was this summer.

In fact, for many of us, this was the hottest summer yet in our lifetimes! Oh, and Amy, please send us a pic of the new baby. We’d love to share it here!

If you would like to send me a weather question, email justaskjohn@local12.com or just visit this link: http://www.local12.com/content/weather/justaskjohn_mail.aspx.

What Was the High on....?

Jason from Lebanon asks:

Hey John, I got a question for you. Where could I find information containing temperature records and averages? I know Local 12 broadcasts the records and averages on a daily basis but I'm looking for something where I could just flip to a certain date and see the record highs, record lows and avarages. I've searched and searched online with no luck. Thanks a lot!

Ed from Burlington asks:

I AM LOOKING FOR A LISTING OF MONTHLY HIGHS AND LOWS FOR THE PAST 5 YEARS AND DECADES IF POSSIBLE. WKRC VIEWING AREA. CAN YOU HELP?

Yes Jason and Ed, I can! Some of the data you need is available from the National Weather Service in Wilmington, OH. To access their climate data, just click here:

http://www.weather.gov/climate/index.php?wfo=iln

To access climate data from years past, select "Preliminary Climatology Data" from the menu on the left. There is also a section for daily records for the entire year.

For any further data not listed, you may want to visit the National Climatic Data Center: http://www.ncdc.noaa.gov/oa/ncdc.html

If you would like to send me a weather question, email justaskjohn@local12.com or just visit this link: http://www.local12.com/content/weather/justaskjohn_mail.aspx.

Grass Skirts and Sunny Skies

Charlie from Westwood Asks:

I’m thinking of retiring pretty soon. What city in the country is the safest from bad weather and other natural disasters?

Charlie, that’s a great question. And here’s the short answer: NO city in the United States is immune to bad weather and other natural disasters! No matter where you live, there’s the chance that you could see anything from hurricanes, to floods, to tornado outbreaks, snow storms, earthquakes or wildfires.

However, Forbes Magazine did a study to find out where you are LEAST LIKELY to experience extreme weather and other natural disasters. Topping that list? Honolulu, Hawaii.

According to FEMA, between 1972 and 2000, Hawaii only had a total of 12 major disasters declared, a relatively low number compared to other states. Of course, hurricanes can happen there – but not too often. The last one was in 1992 with very little damage. Hawaii, however, can be impacted by tsunamis. But the last time someone died from one was in 1970 when a few people drowned when camping on the coastline. And yes, there is an active volcano on Hawaii’s Big Island, but it’s not a big threat right now.

Other safe places include Boise, Idaho and Santa Fe, New Mexico and Yakima and Spokane, Washington.

The least safe place in the country from extreme weather and other natural disasters? Monroe, Louisiana. The dual-combination threat from hurricanes and tornadoes makes it #1 on the list.

To see the complete report yourself, head here: http://www.forbes.com/realestate/2005/08/30/safestplaces-insurance-realestate-cx_sc_0830home_ls.html

If you would like to send me a weather question, email justaskjohn@local12.com or just visit this link: http://www.local12.com/content/weather/justaskjohn_mail.aspx.

Furry Meterologists

(video link)

Nick from Union asks:

I would like to know if cows have the power to predict the weather because whenever they are laying down it rains or snows and when they are standing up there is no precipitation???

And on a related note,

Catherine from Walton Asks:

"I’ve heard that animals can sense weather and other natural disasters before they happen. Is this true?"

Catherine, you’re right. Since the dawn of time people have believed that animals can sense changes in weather and other natural disasters before they happen. In fact, during the big 2004 tsunami, there were many reports of elephants running for higher ground before the tsunami hit. Now, I'm no animal expert by any means. But I do have a dog. And I've owned turtles and fish before. With the exception of my dog, none of them seemed to sense bad weather. My dog, well, let's just say he doesn't like thunder. And he's usually the first to hear it in my house. The poor little guy will start shaking uncontrollably when storms approach. But because I'm not an expert in this area, I decided to go to the Cincinnati Zoo and talk with Thane Maynard. Here's how our conversation went:

John: “Alright Thane, so what’s the deal? Can these animals actually sense changes in weather and other natural disasters? "

Thane: "Absolutely. Wild life not only has a sixth sense John, they have a 7th, 8th and 9th sense. At your own house you might see that. Dogs can hear frequencies that we don’t. All birds and insects can see wavelengths of light that we don’t see. So animals are adapted to see the world differently.”

So while those animals may not be taking my job just yet, they are certainly more sensitive to the environment than we are. Most likely, they are sensing changes in barometric pressure or electromagnetic fields that accompany storms. Or in the case of the tsunami, actually hearing infrasonic sounds or detecting subtle vibrations that scare them to safety.

My thanks to Thane Maynard, Schotzie the elephant, and everyone else at the Cincinnati Zoo who helped with the video above!

If you would like to send me a weather question, email justaskjohn@local12.com or just visit this link: http://www.local12.com/content/weather/justaskjohn_mail.aspx.

(video link)

Joe from Milford asks :

"If hot air rises, why is it warmer at the ground than it is up high?"

Joe, it’s true hot air rises, but air gets cooler as it rises. The reason for this? Well, it all has to do with air pressure…dropping.

The air we breathe in is made up of tiny particles called air molecules. Now think of cheerleaders in a pyramid. The pressure on the bottom cheerleaders is much greater than the pressure on the top cheerleaders. It’s the same for those air molecules. As the molecules on the bottom press together…or in this case…the cheerleaders…they get warmer. Meantime, the molecules (or cheerleaders) up top are nice, cool and cozy because they don’t have as much weight above them.

So typically, things get colder as you go up, but every once in a while things get flipped around. That’s what we call a temperature inversion. It’s kind of like putting a lid on a pot. This lid will trap pollution near the surface and lead to smoggy conditions. And it can also lead to fog and even sometimes prevent rain and thunderstorms from developing.

Another factor to take into account is the ground. The air around us is not heated directly by the sun, but rather the sun passes shortwave radiation (UV rays) through the air which heat the ground. The ground then absorbs this shortwave radiation and reemits it as longwave radiation or heat as we know it. So the air around us is actually heated by the ground. That's another (but smaller) factor in the reason things are warmer closer to the ground.

My thanks to the Anderson High School cheerleaders for their help in answering this question in the video above!

If you would like to send me a weather question, email justaskjohn@local12.com or just visit this link: http://www.local12.com/content/weather/justaskjohn_mail.aspx.

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