主播大秀

(Scott Sistek is a meteorologist and producer for KOMONews.com. He has been producing weather reports for broadcast and the web since 1994 and can be found on the weather blog. Keep up to date with Scott via )

Distance travelled ~ 934'891'200 km

The Pacific Northwest is known for its beauty, from the lush greenery to the tranquil waters to the majestic mountains. But no mountain is as iconic to the Northwest as Mt. Rainier, which stands just over 14,000 feet tall about 70 miles southeast of Seattle.

But while the Seattle area is world famous for its rainy, cloudy weather, at times, Mt. Rainier can act like its own paintbrush and using the sky as its canvas, bring a whole new awe-inspiring level to a "cloudy" sky. Thanks to it's status as the tallest peak around and its unique position to catch the moist jet stream, it flows in off the Pacific Ocean - Mt. Rainier can create its own weather patterns.

Perhaps the most dramatic are its frequent lenticular cloud displays. Seen maybe a dozen times a year, it still looks amazing every time it's showcased.

The cloud is formed when warm, moist air runs into the surface of Mt. Rainier. The mountain's topography forces the air upward, which cools and condenses the air -- turning it into a cloud. As the air sinks back on the other side of the mountain, it dries out and the cloud dissipates. That's why it just hangs over or near the summit area. (Although it looks like it is "hanging" over the mountain, air is continually flowing over the summit.)

Sometimes if the atmospheric set up is just right, you can get layers upon layers of stacked lenticular clouds that combine to make dramatic shapes -- many times mistaken for UFOs years ago.

Locals have used this cloud as a sign that rainy weather is on the way -- many locals might think the cloud is the mountain's version of an umbrella? -- as that cloud usually occurs with west or southwesterly flow in the upper atmosphere, a usual precedent to rainy weather. However, that's not always the case -- especially in the summer. Then, it can just be an indication that we have a good westerly, marine flow and that it won't be too hot anytime soon.

Or on rare occasions, the mountain can have the opposite effect, as seen here:

This time, the mountain caused some turbulence that created some sinking air in the vicinity of the mountain peak. Sinking air dries as it does so, in essence "eating" away a hole in the cloud!

Finally, when the mountain isn't creating or destroying clouds, it can just put on a show using the clouds that are already there.

In the autumn and early winter in the Seattle area, the Sun's position on the horizon during sunrise is just in the exact right spot to where Mt. Rainier will cast a shadow against a cloud layer!

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So while yes, it rains a lot around here, there are plenty of advantages to living in an area with such unique terrain and meteorology!

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Distance travelled ~ 932'318'400 km

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It鈥檚 very liberating to be completely and utterly soaked by a rainstorm, especially when what鈥檚 falling out of the sky are raindrops the size of large peas.

I tried to explain this to the director and crew who were huddled beneath enormous umbrellas, missing out on all the fun. They were not convinced. They had not come to India during the monsoon to get wet. That was my job.

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The thing is, weather is fun. We are brought up to hide from it a bit, to carry on (usually with a British stiff upper lip) in spite of it. But it鈥檚 not going away, so I think that we might as well appreciate it. As long as it鈥檚 not giving you hypothermia or sunburn, why not just play with whatever the atmosphere is doing today?

For 23 degrees, we鈥檝e been lucky enough to travel to some fantastic places in our global weather patterns. Different parts of the planet receive different amounts of energy from the Sun, and this is just the start. That energy is carried around the planet by the ocean and atmosphere, and the result is a giant pattern of hot and cold air, dry and moist air and huge swirling wind systems. The pattern is never exactly the same from one year to the next, but there are features that are present all the time (tropical thunderstorms and the jet stream), or that return every year (spring showers and hurricanes).

Two things have stood out for me. The first is how little we appreciate the depth of the atmosphere. I realized this properly while looking at the tornado we found in June.

It鈥檚 almost certainly the biggest thing I鈥檝e seen whose scale I鈥檝e been able to understand. We know that the clouds are high up, but until you see a single thing joining the clouds to the ground, you have no idea what 鈥渉igh up鈥� means. The atmosphere is big, vertically as well as horizontally.

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The second thing is how little we actually look at the sky, especially in Britain. We鈥檙e too busy getting on with things on the ground, and anyway there are lots of buildings and trees in the way. Above us thousands of tonnes of nitrogen and oxygen are flowing around, carrying water and energy, and all we do is complain about it when it gets uncomfortable down here. But if you look up, you can usually see some of the structure of the atmosphere, and that gives you a hint about the larger scale patterns that cover our continent and our planet. Next time you look up at the sky, imagine how all this is connected to the weather over Iceland and Morocco and Costa Rica.

The last day of filming for this series was on the south coast of England, near Beachy Head. We haven鈥檛 done that many days filming in the UK, and it was as though the weather was determined to prove that it shouldn鈥檛 have been neglected.

As the day went on, we had incredibly hard rain followed by hail, very strong winds and occasional spells of sunshine. My boots filled up with water and at the end of the day I felt as though I鈥檇 been in a giant washing machine for a few hours. It was impossible not to be impressed by what the atmosphere was up to, even on our own doorstep.

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(Peter Gibbs is a 主播大秀 weather forecaster and appears as an expert meteorologist on "The Weather Show" for the 主播大秀 News channel. He started his first guest blog post for 23 degrees with 'What would happen if the Earth spun the other way' and provided much food for thought with his post on 'Abundance in fruits indicator to past British weather'. His post on 'What's in a name' cleared some misunderstandings that where flying around the web as remnants of hurricane Katia stirred it's way to the UK, and he provided us with a breakdown of the difference between cyclones, typhoons and hurricanes with his post on Cyclone Yasi. Keep up to date with Peter Gibbs - )

Distance travelled ~ 929'745'600 km

It may seem surprising, but weather forecasters need to take a rather parochial view of the world. At an airport, the forecaster has to predict cloud base, visibility, wind speed and direction in great detail over a few hours for a very specific location. Even a forecaster with a national brief will tend to concentrate only on the weather systems moving across that country and give no more than a passing glance to the storm spiralling across neighbouring areas.

One of the advantages of working as a weather broadcaster on 主播大秀 World is that I get to see the whole picture and can begin to understand the interactions of the global weather system with its regular seasonal pulse. A group of thunderstorms produces newsworthy rainfall as it tracks westwards across equatorial Africa, grows into a hurricane over the tropical Atlantic to threaten east coast America, then gets caught up by the jetstream and races across the north Atlantic to bring rain and gales to northwest Europe, passing through several forecast jurisdictions en route.

Other rhythms overlay the annual one. Swings from El Nino to La Nina take place over periods of several years and enhance or diminish normal seasonal features, especially rainfall. 2011 has been mostly a La Nina year,

with unusually warm water washing into the western side of the Pacific. The extra atmospheric moisture this provided was the likely cause of January deluges in Sri Lanka and the Philippines, as well as the extraordinary where an area the size of France and Germany was underwater for a time.

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Continental landmasses tend to produce the biggest temperature contrasts and hence the most violent weather, especially during the transitional periods of spring and autumn. for tornadoes in the USA with an estimated 600, smashing the previous April record of 257 and even beating the all time monthly record of 542, set in May 2003. Arctic air pushed further south than usual, meeting air from the exceptionally warm waters of the Gulf of Mexico and combining with a jetstream pushed unusually far south by La Nina.

As the Atlantic warmed, an active hurricane season was expected and the with a total of 19 named storms, of which seven became hurricanes including three major hurricanes of category 3 or above. Surprising then, that we had to wait for a record eight tropical storms to come and go before our first hurricane. But once formed, hurricane Irene made the biggest impact, passing through the islands of the northern Caribbean before becoming the first landfalling hurricane in the USA since 2008.

La Nina was in the dock again as the likely culprit when weeks of heavy rain produced some of the worst floods on record in . The monsoon season started early and finished late, meaning there were even greater volumes of water than usual flowing from the mountainous north to the low-lying plains of the south.

Having a global perspective makes me even more appreciative of our UK climate. The British Isles are at the crossroads of European weather. Atlantic winds are a moderating influence, while the proximity of continental Europe can provide bigger swings from hot to cold. Last December found me gliding on Nordic skis across the snowfields of Berkshire, while this December the Christmas journeys to friends and family will be easier on roads kept clear of snow and ice by mild westerlies. There is the excitement of the occasional mid-latitude depression or summer thunderstorm, but without the devastation of hurricanes and monster tornadoes.

Meteorological variety without the jeopardy. If you have to be a parochial forecaster, the UK isn't such a bad place to be.

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(Jason Samenow is the weather editor. He founded Capitalweather.com in early 2004, the first weather blog on the web which was absorbed by the Post in 2008. He can be reached via )

Distance travelled ~ 927'172'800 km

A strong case can be made that 2011 was the most extreme weather year on record in the U.S. In addition to the record of at least 12 weather events that produced more than (totaling more than ), never has a larger percent of the country dealt with either extreme drought or abnormally heavy precipitation.

The U.S. contended with virtually every kind of weather hazard including mega snowstorms in the Midwest and Northeast, historic flooding of the Mississippi and Missouri rivers, devastating wind and flood damage from tropical weather systems (Irene and Lee) in the East, and one of the worst spring tornado seasons in memory. The tornado outbreaks that ravaged the central and southern U.S. between April and June resulted in more than 500 deaths, tied second most on record. Several exceptionally strong tornadoes struck densely populated areas including Birmingham and Tuscaloosa in Alabama as well as Joplin, Missouri.

Perhaps the most notable weather to afflict the U.S. was the devastating combination of extreme heat, drought, and wildfires in the South Central U.S. Texas was particularly hard hit. Exceptional drought gripped almost the entire state and groundwater, lake, and reservoir dropped to historic lows. The state suffered its worst wildfire season, with more than 4 million acres burned. In July, neighboring Oklahoma's average temperature was the hottest of any state in 130 years of U.S. weather records, a searing 88.9 degrees.

Undoubtedly, the moderate La Nina pattern set the stage for the unusually volatile weather conditions across the U.S. It helped fuel the powerful jet stream slicing through the middle of the country, bringing the onslaught of stormy weather. But to the south and southwest of that jet stream, a stifling heat dome blossomed and the moisture abruptly shutoff leading to historic drought.

Although global warming should not be blamed as the root cause of this punishing set of weather conditions, it very likely amplified the sharp contrasts in this pattern. The added heat in the atmosphere presumably juiced up the wet extremes by making more water vapor available, while speeding up evaporation and drying in drought areas.

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Distance travelled ~ 924'600'000 km

23 Degrees is coming to an end, but what a journey it has been and what a year.

Coming into this project we didn't have any expectations, well I didn't anyway. I think we all appreciate that it's hard to predict the weather. The most extreme tornadoes in the US mid West, huge cyclones like Yasi hitting Australia, record snows in the US and the UK. Our mission when we set out on 3rd january 2011 (the day of Perihelion) was to tell the story of Earth's annual journey around the Sun.

So what has this year's weather shown us?. That's a really difficult question.

Making 23 Degrees has had a huge impact on me, I have learnt how our climate and our weather is all generated by our orbit around the Sun. It's all interconnected. It really does feel like a huge single organism where everything is linked to create our extraordinary world. I have always liked James Lovelock's idea of Gaia, the Earth as a single organism and seeing how land , sea and atmosphere all interact powered by the Sun has made me want to look into Gaia more.

It has been a real privilege to work on this series and get a glimpse of our incredible planet's annual journey. I just hope we humans step closer to more action in limiting the affects we have on our climate.

It would be great to hear which weather events of 2011 stand out for you?

(Keep updated - The series will transmit early 2012)

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