October 5 – How Low Can You Go?

Today’s factismal: The most intense Atlantic hurricane ever recorded was Wilma, with a low pressure in the eye of just 882 mbar.

If you are a meteorologist, then 2005 is probably your favorite year. Over the course of the year, there were so many tropical storms that they ran out of names and had to resort to using Greek letters. Of the 28 storms that developed, a record high of 15 would go on to become hurricanes and seven of those would become major hurricanes. And none of those was more major than Wilma.

Wilma at peak strength (Image courtesy NASA)

Wilma at peak strength
(Image courtesy NASA)

Wilma started as a tropical depression off of Jamaica on October 15. Two days later, she had become a tropical storm. By the 18th, she was a full-fledged hurricane and showing no signs of getting any weaker. Indeed, where most hurricanes are big, ungainly monsters with large eyewalls (which often indicates a weaker storm), Wilma had a fairly compact eyewall just two miles across (the smallest known) and peak winds of 185 mph! Those factors combined to give Wilma the lowest known pressure of any hurricane at just 882 mbar; to put that in perspective, remember that normal air pressure at sea level is 1013 mbar. In effect, the center of Wilma was at the same air pressure as Denver!

Naturally, a storm this intense caused lots of damage. Wilma killed at least 62 people (mostly through flooding and landslides) and caused $29 billion dollars in damage. Many of the deaths happened because Wilma’s path was unusually unpredictable; she changed directions several times, making it harder to know where she would hit. What the meteorologists needed was more observations in order to give better predictions. What they needed was people like the members of the Citizen Weather Observer Program who send in reports about severe weather (and the other kind, too) that is then used to make better predictions. If you think that you’ve got what it takes to be a CWOP member, head over to:

September 21 – The Heat Is On

Today’s factismal: This summer was the warmest since we started keeping records in 1880. The previous record-holder was last summer.

If you think that it was just too darn hot outside this summer, you aren’t alone. Meteorologically speaking, this summer (June, July, and August) was the warmest that we’ve ever recorded. Even more interesting is that the previous record holder was last summer. And even more interesting than that is that we’ve had fifteen months in a row of record warm temperatures, globally speaking. And even more interesting than that is the last time we had a global average temperature that was below average was back in December of 1984 – 32 years ago! And the last time we had a year that was cooler than average was in 1976 – 40 years ago!

The average global temperature has risen quite a bit in the past 136 years (Data courtesy NDC)

The average global temperature has risen quite a bit in the past 136 years; the blue line is the 20th century average global temperature
(Data courtesy NDC)

So why are we getting warmer? It is no secret; as a matter of fact, this very thing was predicted back in 1896 based on a discovery made in 1859. It is the CO2 that we are adding to the atmosphere. CO2 happens to block some of the “heat radiation” given off by the Earth. This is reabsorbed by the atmosphere, raising its temperature slightly. (Think of it as being like the interest given to you by a bank. You give them a dollar and every year they give you four cents more as interest. Over time, that interest builds up and so does your bank account.) Of course, lots of other factors come into play when you are talking about a planet , so the temperature change isn’t instantaneous and it has some wiggles in it. But overall, the pattern is clear: increasing CO2 increases temperature and changes climate.

The change from the 20th century average temperature. Blues are colder than average; oranges and reads are warmer than average. (Image courtesy NOAA)

The change from the 20th century average temperature. Blues are colder than average; oranges and reads are warmer than average.
(Image courtesy NOAA)

As a citizen scientist, there are two sets of things you can do. The first is to reduce the amount of energy you use; a nice benefit of this is that you also save money. For example, making sure that your tires are properly inflated will save you the equivalent of $0.10 per gallon and save the US the equivalent of 1.2 billion gallons of oil. Adding a layer of insulation to your water heater (like that blanket on your bed) will save you about $30 per year and save the US another 500 million gallons of oil. There are plenty of other way you can save money while saving the planet. But if you still want to do more, why not help record the changes that global warming is bringing to your neighborhood? Join the Citizen Weather Observer Program and help them monitor how temperatures, weather, and other things are changing. To learn more, head to:


September 15 – My Beautiful Balloon

Today’s factismal: The world’s first weather balloon was launched 112 years ago today.

Meteorologists in St. Louis, Missouri, have something to celebrate today. More than a century ago, they launched the very first weather balloon intended for use in weather reporting. Though scientists had been launching balloons with scientific instruments since 1896, this was the first balloon intended to be used specifically for predicting the weather. The balloon carried a recording thermometer and a pressure gauge in a small package that was recovered after the balloon burst in the stratosphere. Today, the National Weather Service launches balloons from 92 sites in the USA; they are just part of the more than 900 sites that launch twice a day (morning and evening) to get information.

Launching a weather balloon during World War II (Image courtesy NOAA)

Launching a weather balloon during World War II
(Image courtesy NOAA)

So why would they bother? Simply because we knew then as we know now that it isn’t enough to measure the temperature and pressure and other weather factors in just one place; if you want an accurate prediction of what is going to happen next, you need lots of data that goes up through the atmosphere as well as across the globe. And balloons do that! They can rise as far as 20 miles before they pop, and they will fly up to 125 miles away. Each year, some 75,000 instrument packages are sent up in weather balloons. And thanks to WiFi, we are getting more data than ever from them.

A modern weather balloon launch (Image courtesy NOAA)

A modern weather balloon launch
(Image courtesy NOAA)

But that’s still not enough to make the meteorologists happy. (That’s a meteorologist for you – always raining on our parade!) They want more data – and that’s where you come in! They have set up a group to record temperature, pressure, and (most importantly) precipitation. Known as CoCoRAHS, these folks feed valuable information to the meteorologists who use it to make better weather predictions. To learn more, float on over to:


September 2 – An Ill Wind

Today’s factismal: The lightning in a Category 1 hurricane has enough power to run a house for more than 300 years.

If you read the news today, you know that Hurricane Hermine has come aground in Florida. This ended the long dry spell for hurricanes damaging the US mainland (though Sandy was a hurricane in 2012, it had been downgraded to tropical storm before it came ashore); it was the first time in eleven years that the US mainland was hit. Of course, you don’t have to get a hurricane to get lots of storm damage, just ask the folks who sat through Sandy or Allison. Although it is too early for firm estimates, experts think that the damage from this storm will end up costing the US at least $5 billion.

A satellite image of Hurricane Sandy showing the temperature differences in the clouds (Image courtesy NASA)

A satellite image of Sandy showing the temperature differences in the clouds
(Image courtesy NASA)

So what causes all of that damage? The short answer is “energy”. Hurricanes are nature’s way of taking heat from the equator (where it is hot) and moving it to the poles (where it is cold). They do that by using the heat to evaporate water, which forms clouds, which forms storms. Because that heat also causes the air to expand, it drives winds which can drive water in the form of storm surge. Add it all together and you’ve got a lot of energy moving around, looking for something to break – like Florida.

Hurricane Hermine making landfall in Florida (Image courtesy NOAA)

Hurricane Hermine making landfall in Florida
(Image courtesy NOAA)

But how much of the storms energy is released by the different parts of a hurricane’s life cycle? Scientists have run the numbers and found that a hurricane typically releases about 0.002% of its energy as lightning. Now that may sound like small potatoes, but for a Category 1 hurricane, it works out to be enough energy to run a typical household for 360 years or so. (The trick is catching the lightning.) Storm surge is what does most of the damage along the coast and yet it is just 0.02% of the total energy of the hurricane. The winds in a hurricane are what creates that lightning and tornadoes and other exciting side-effects. They are understandably much more powerful; they represent about 4% of the total energy in a hurricane. Interestingly, the sheer weight of the water falling from the sky as rain and hail releases about as much energy as the wind does. Thus far we’ve accounted for about 9% of the energy in a hurricane with the lightning and the storm surge and the winds and the rain. Where is the rest?

Some of the effects of a hurricane (Image courtesy NOAA)

Some of the effects of a hurricane
(Image courtesy NOAA)

It is released high in the sky as water vapor condenses into rain drops and is known among meteorology wonks as the latent heat of vaporization (which is just a fancy was of saying “the heat stored {latent} in vapor”). As the water vapor is carried higher into the atmosphere by the rising air currents, conditions change so that water vapor is no longer stable and water is; this is what forms clouds (which are just raindrops that are too small to fall). When the water condenses, it gives back some of the energy that was used to turn it into a gas; the rest of the energy has gone into raising the vapor high into the sky and powering all of the other special effects.

But here’s the odd thing. Even though we can use satellites to track hurricanes and help people get out of their way, we still don’t know how reliable our satellite images of the clouds that make up hurricanes are. And that’s where you come in. NASA has a citizen science program called S’COOL that asks for people like you and me to tell them what clouds are out there when the satellites pass by. To participate, float on over to:



August 26 – Well, Blow Me Down

Today’s factismal: The “Year Without A Summer” was not caused by the eruption of Krakatoa.

Stop me if you’ve heard this one before – way back when, there was a massive volcanic eruption that was so loud it was heard in Australia and put so much ash into the air that everything froze and we had a year without a summer. Great story, right? The only problem is that it isn’t; instead, it is two great stories.

The eruption of Mt Saint Helens was actually fairly small as such things go (Image courtesy USGS)

The eruption of Mt Saint Helens was actually fairly small as such things go
(Image courtesy USGS)

The first story is actually the last one. Back in 1815, Mount Tambora in Sumbawa exploded in the largest volcanic eruption in recorded history. It turned 24 cubic miles of rock into dust and debris and was loud enough to be heard for 1,200 miles. The eruption alone killed some 11,000 people. Worse, all of that dust in the air dropped the global temperature by a full degree below which was enough to kill crops and cause starvation in many areas; experts estimate that this killed another 60,000 people. (For comparison, the global temperature is now nearly two degrees above average this is not a good thing, either.)

When Pinatubo erupted in 1991, it cooled the planet by about 0.25 °

When Pinatubo erupted in 1991, it cooled the planet by about 0.25°

The second story happened nearly 68 years later at a spot nearly 900 miles away. On August 26, 1883, Mount Krakatoa erupted violently. The eruption wasn’t a surprise as the mountain had been spewing “fire fountains” into the air for months. What was a surprise was the size of the eruption; experts think that the neck of the magma chamber had become plugged with debris. Like holding your thumb over the neck of a soda bottle while shaking it, that allowed the pressure to build until it finally spewed out. That would have been bad enough, but the eruption created a caldera that went down below sea level. As the ocean water rushed in, it created a phreatic (steam) explosion, resulting in a sound so loud it could be heard 2,600 miles away and a tsunami that devastated coastlines across the Pacific and killed some 36,000 people. Because this was a smaller explosion than Tambora, only a few cubic miles of dust were tossed into the stratosphere and the weather was only made chilly instead of cold. As a result, there wasn’t the mass starvation of the previous eruption.

Exciting as the two eruptions were and interesting as the volcanology is, there is another facet to the two events that has a far more practical effect on us today: their effect on the weather. Since modern meteorological systems weren’t in place during the two eruptions (heck, meteorology hadn’t even been invented when Tambora blew!), climatologists must search for clues to their effects using old ship’s logs and diaries. And that’s where you come in. At Old Weather, you can look through the logs of sailing ships to discover what the weather and other things were like. By highlighting those entries, you help the folks who are trying to figure out what our new weather will do next. To learn more, blow on over to:

June 17 – In A Fog

Today’s Factismal: Fog is not considered to be precipitation by meteorologists.

If you’ve taken a fifth grade science course, then you’ve probably learned about the water cycle (or, if it was in a fancy school district, the hydrologic cycle). In this cycle, water evaporates from ocean, rivers, and lakes, goes high into the air to form clouds, and comes back down as rain and snow. It is a beautiful, simple model. And like most such things, it is too simple and not nearly beautiful enough.

When you ask a meteorologist about the hydrologic cycle, then you’ll get the full, juicy story. Water doesn’t just evaporate from lakes, rivers, and oceans; oh, no! It also comes out of plants that have sucked water up from the ground (sometimes from several hundred feet underground), used it during photosynthesis and then sweat it out as part of their temperature regulation in a process known as transpiration. Over the course of a year, a single large oak tree can “sweat” out enough water to fill two swimming pools! Transpiration from plants and evaporation from the soil itself may account for as much as 67% of all precipitation.

This fog is not precipitation (My camera)

This fog is not precipitation
(My camera)

OK, you say; so the water sources are a bit more varied than we thought. But at least we know what precipitation is. However, this turns out to be another of those places where non-scientists and scientists use terms differently. To a meteorologist, it is only precipitation if the air becomes so saturated in water vapor that the water comes out and condenses around a small particle (that’s the “precipitate” part) and then (here’s the tricky part) falls under gravity. If the water drops are too small to fall, as they are in mists and fogs, then it technically isn’t precipitation even if it is on the ground (e.g., dew). But if it falls and evaporates on the way down, it is precipitation even though it stays in the air; meteorologists call this type of precipitation “virga”.

Virga falling from a cloud in Florida (My camera)

Virga falling from a cloud in Florida
(My camera)

And the hydrologic cycle gets more interesting still once we consider all of the types of precipitation that we can get. There’s virga and rain and hail and snow and sleet and graupel and drizzle, to name but the seven best known. And here’s the truly interesting part: meteorologists still have to rely on people on the ground to help them discover what kind of precipitation is falling where. Though some progress has been made in using radar to discriminate between the various types of precipitation, radars don’t see very well near the ground (all those pesky buildings get int he way). So they need observers to tell them what is falling where, be it thundersnow or nonaqueous rain.

The drizzle on Uluru is a form of precipitation (My camera)

The drizzle on Uluru is a form of precipitation
(My camera)

If you’d like to help, then why not download the National Severe Storms Laboratory’s free mPING (Meteorological Phenomena Identification Near the Ground) app? It is available on both Android and Apple devices. All you have to do is use the app to send a report whenever you see precipitation; the app will even help you decide what type of precipitation it is. To find out more, go to the National Severe Storms Laboratory mPING webpage:

May 2 – Islands In The Stream

Today’s Factismal: The Gulf Stream was “discovered” 231 years ago today.

What constitutes being “discovered”? Is is when someone, somewhere, first thinks of something? Or is it when the first bits of evidence that it might actually exist are found? Or is it that “Eureka!” moment when all of the pieces finally fall into place? Well, for scientists, the answer is “none of the above”. For us, something gets discovered when it first gets published. That’s why Brontosaurus lost its name and why Newton never got along with Leibniz; the “wrong” person published first.

And as far as the English were concerned, Benjamin Franklin was the wrong perons. Even though he was America’s first and foremost citizen scientist, the English didn’t like him and refused to listen to many of his ideas simply because they refused to trust any  group that would throw perfectly good English Tea into an American harbor. Unfortunately for the English, that intransigence would come back to bite them in the wallet.

That’s because Benjamin Franklin discovered a faster and safer way to move ships from Europe to America. Then as now, time was money. By using Franklin’s discovery, the American ship captains were able to save one and make the other while English captains refused to listen to the upstart. So what was this amazing discovery? Franklin charted Gulf Stream.

Benjamin Franklin's chart of the Gulf Stream

Benjamin Franklin’s chart of the Gulf Stream

What originally spurred Franklin’s curiosity was a complaint from his boss in England. Ships sailing from Cornwall to New York took much longer to arrive than ships sailing from London to Rhode Island, and his boss wanted to know why. So Franklin went to his brother-in-law, who was a whaler from Nantucket, and asked him. The answer, his brother explained, was because the ships sailing from London rode with a current that flowed from Europe to America while those sailing from Cornwall went against a current that flowed from America to Europe. The whalers knew about the current because it was also rich in fish and whales. This inspired Franklin and he named the putative current the “Gulf Stream” in 1762. For thirteen years, Franklin worked with his brother-in-law and other sea captains to produce a map of the current, which they then published in 1775, just one year before America would declare its independence. But, with typical British intransigence, the English sea captains decided to ignore the “Yankee map”.

Franklin’s interest in teh Gulf Stream lasted for his entire life. On every trip back and forth to Europe, he took careful measurements of everything from location to water temperature, salinity, color, and wildlife. During the last few trips, Franklin even brought along a weighted barrel fitted with valves so that he could capture water from several fathoms below the surface for measurement. He finally compiled all of his results and published them on May 2, 1785, putting the final flourish on work that had begun 23 years earlier.

But Franklin couldn’t have accomplished his work without the contributions of the ship captains who helped him chart the current. Today, scientists are attempting to learn more about severe weather using Doppler radar. And they need your help to refine their data, just as Franklin needed the ship captains. All you need to do is look outside the next time it rains or snows and tell the scientists at the PING network what conditions look like on the ground. To help, go to the PING project: