Dan's Wild Wild Science Journal

Every time we get a big blast of cold in the Tennessee Valley, I get several requests for a wind chill chart. If I have reminded you of such a forgotten need, not to worry!  I am including one in this post.

However, if you think that the wind chill is “How cold it feels”  then let me persuade you otherwise. It really is not. What wind chill IS, is a measure of the rate of heat loss on exposed skin. It makes a number of surprising  assumptions. If you have a wind chill chart more than 10 years old, it’s wrong anyhow.

First a little history!

The term “WIND CHILL” was first coined by an Antarctic explorer named Paul Sipple in 1939. He and some others did experiments on how long it took a plastic container of warm water to freeze. They realized that the time was a function of the wind speed, and the outdoor temperature together.

To put it in plain terms, how fast something will cool off, depends on the starting temperature, the current temperature, and the wind velocity.

Wind chill is a good indicator of how long it will take for hypothermia or frost bite to occur. It IS NOT a measure of how cold it feels. Also, water will not freeze at 33 degrees, no matter how hard the wind blows! The wind chill is also a good measure of how quickly your car engine will cool off on a cold night!

The equations developed by sipple in the 1940′s were looked at a bit more rigorously in the 1990′s by Meteorologists and in 2001, NOAA and the NWS revamped the wind chill. In general, the new scale will not show as cold a wind chill as the old one did. Especially in stronger winds. If you are in another country, the wind chill may be calculated a bit differently. There is no right or wrong way. It depends on the assumptions you make!

Wind chill is actually a bit controversial. Many Meteorologists, like myself, are not real fans of it. The public generally misunderstands it, and gives it more credence than it really should have.

You should also know that the wind chill equations assume the following.

 It is night time.

Skies are clear.

Your 5 feet tall.

 If the sun is shining on your skin, that will reduce considerably the effect of the wind. I have,  somewhere,  the complete paper published in the peer reviewed journals on the new Wind Chill. If you really want it, email me, and I will try and find it!

I frequently get requests from viewers for the actual equations, not the chart. (Huntsville has a lot of rocket scientists with NASA in town!) Many times, the viewer will think that it’s as simple as adding, or multiplying the wind, and the temperature. It’s not. It is, however, just a basic Algebraic formula.

Here it is for Degrees C:

WC = 13.12 + 0.6215 T_C + ( 0.3965 T_C – 11.37) V ^0.16

TC= Temp. in Celsius V= Wind speed in mph

(Courtesy NSDL/NOAA)

If you just want the chart..here ya go!

Later,

Dan

There have been large hints on the Numerical Weather Prediction Models (NWP) for the last two weeks that the warm, and wet weather over the Southeast USA was going to change. There is no longer any doubt, as all that frigid air bottled up in Canada, is headed into the Deep South.

Below is the GFS temperatures at 5,000 feet (850 Hpa for my fellow weather nerds out there). It has the zero C line way down into Northern Florida later this week. Not only that, but it looks like this Pacific Ridge and Eastern Trough pattern may lock in for a couple of weeks! We Meteorologists call this a positive PNA pattern, and it means mild West, and cold East here in North America.

Those of you in Western Europe, and the UK, can finally expect some moderating temps. as the pattern changes are nearly global. The image below is courtesy Unisys. They have an exc. site for looking at NWP data at weather.unisys.com.

So bundle up, and for those of you in the South who wonder how the folks up North survive these temps. They wear a HAT, and gloves. Try it. They are amazing inventions!

Later,
Dan

The scientists who work at the National centers For Atmospheric Research (NOAA) have produced some excellent short movies about Climate Change. They are designed to answer some of the common questions that many people have. These are basic primers and teachers may find them of great use. Especially middle school and up. Not really suitable for elementary age.

NCAR CLIMATE VIDEOS

There continues to be almost no info on climate change for the young elementary age students. I am working on a keynote presentation (power point for Mac for all you unbelievers in the PC world). It’s not easy though!

There is a ton of more advanced material on their site and you may find it worth your time exploring it.

This post is actually a substitute for a diatribe on the condition of roads in Oklahoma, that I really want to write about. I grew up in Tulsa, and we always knew we had the worst roads in the nation. So how is it possible for them to actually get worse. I will say nothing about the hideous architectural monstrosity called the BOK center. The entire London city planners of the 1970′s couldn’t beat that.

It’s good to be back home in Alabama. In spite of the fact that when I walk out into my yard I sink to my ankles in mud. 17 inches of rain in the last 37 days.

This is getting ridiculous!

It’s time for some unimportant posts (Well relatively)..so my next two posts will be an ode to the wisdom of one Stephen Fry. The other will be a tongue lashing to the Brits who do not realize what a rare GEM they have in the BBC.

BBC= NPR with some money.

Later,

Dan

If you ask any Synoptic forecaster like myself, what the number one weather killer is, you will likely get the same answer.

It doesn’t matter if it’s a private TV Meteorologist like me, or a NOAA forecaster, or one from Environment Canada, the BBC, or the UK Met. Office.

It’s not tornadoes or hurricanes. It’s heat. (You thought I was going to say flash flooding didn’t you!)
At least in America it’s heat! We are too used to Air Conditioning here.

My grandmother lived through the Dust Bowl in Oklahoma. She would sit outside in 110 degree heat and drink ice tea and feel just fine! I’m a wimp. I hate the heat. (Cold I like!)

Flash flooding is the second most frequent weather killer. It may be number one in many countries. Bangladesh and India come to mind. (Every person I know from India is smart and friendly…I want to go there!)

The “Get there itis” that people have when driving, causes them to drive into a flooded intersection more often than not. If you do the math, (I can send it to you, if you want) you will find that water moving at 10 mph only has to be about 8-12 inches deep to force your car off the road. If the water is moving faster, even less.

People email me all the time who have a real phobia of tornadoes, and hurricanes. Yet they will drive through flooded intersections, and play on a ball field when a thunderstorm is coming. Lightning is almost as deadly as flash flooding.

No we do not issue lightning warnings. (The PGA does!). Perhaps we should. The Psychology of how people react to threats has always fascinated me.  Thousands die each year in road accidents, but a plane crash with 5 fatalities makes front page news.

The U.S. National Oceanic and Atmospheric Administration spent millions on a campaign to get people to recognize the dangers of flash floods. The slogan, “Turn Around, Don’t Drown” was developed. At a recent American Meteorological Society weather conference, a survey of forecasters found that less than half knew it!!

Now at least, YOU DO!

TURN AROUND, DON’T DROWN!

later,

Dan

The folks at Nature (One of the top science journals on the planet), have written an excellent summary of the year’s new knowledge in Climate. It’s another of my must reads. (I admit there have been a few of these lately..sorry I can’t help it).

You can see it HERE

The other news of the day comes from the White City tube stop in London. The BBC has announced Matt Smith is the 11th time lord. David Tennant, you will always be in my heart as the true Doctor, but I wish Matt Smith a huge congratulations…you have have HUGE shoes to fill.

I really must write a post on Doctor Who. It’s the only TV program I watch, but really, isn’t that enough!

Happy New Year to all (except Cybermen and Daleks of course)

Dan