The Flying Saucer At Sunset

Lenticular clouds (Altocumulus lenticularis) are stationary lens-shaped clouds with a smooth layered appearance that form in the troposphere, usually above mountain ranges. One was spotted in Singapore recently...

Eyes Of 30,000 Honeycombs

With 30,000 individual facets, dragonflies have the most number of facets among insects. Each facet, or ommatidia, creates its own image, and the dragonfly brain has eight pairs of descending visual neurons to compile those thousands of images into one picture...

A Kaleidoscope Of Colours, Shapes And Patterns

Spectacular and innovative in design, the Flower Dome replicates the cool-dry climate of Mediterranean regions like South Africa, California and parts of Spain and Italy. Home to a collection of plants from deserts all over the world, it showcases the adaptations of plants to arid environments...

Lightning Strikes, Not Once, But Many Times

Unlike light, lightning does not travel in a straight line. Instead, it has many branches. These other branches flashed at the same time as the main strike. The branches are actually the step leaders that were connected to the leader that made it to its target...

Are You My Dinner Tonight?

A T-Rex has 24-26 teeth on its upper jaw and 24 more on its lower jaw. Juveniles have small, sharp blade-shaped teeth to cut flesh, whereas adults have huge, blunt, rounded teeth for crushing bones. Is the T-Rex a bone-crushing scavenger?

Showing posts with label Clouds. Show all posts
Showing posts with label Clouds. Show all posts

The Southern Sunset Wind

4:35 PM  , , ,  

Singapore
January 2014

The slanted rays of the setting sun wash the laden sky with golden light... 
 
At the mercy of a southern wind, 
a few fleeting stratocumulus puffs break away from the heavy mass and scoot across the sky...

A stunning sunset panorama...


More photos are available on Merlion Wayfarer Goes Green's Picasa at :
Natural Phenomena - Clouds


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Broken Clouds

2:37 PM  , ,  

City Hall MRT Station
Central, Singapore
September 2013

Merlion Wayfarer spotted this display at the City Hall MRT Station. She was stumped - How can clouds (which are soft and fluffy) be "broken"?


She Googled for an answer.

According to the General Weather Glossary at Louisville National Weather Service, "broken clouds" refer to "clouds which cover between 6/10 and 9/10 of the sky". This also means that unlike a typical cloudy day, you get to see the sun peeking out sometimes.

Ok, new term learnt...

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Contrail Streaking Across A Golden Sunrise Sky

8:55 AM  , ,  

Singapore
August 2013
A contrail streaking across the sky at sunrise...

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There Is A Mountain In Front Of Me!

3:54 PM  , , ,  

Singapore 
23 October 2013

Merlion Wayfarer's recent posting on mushrooms and flying saucers in the sky ("The Mushroom That Became A Flying Saucer At Sunset") created so much excitement among her friends that she decided to investigate the rare occurrence of these clouds...

Mushrooms & Flying Saucers

Lenticular clouds (Altocumulus lenticularis) are stationary lens-shaped clouds with a smooth layered appearance that form in the troposphere, normally in perpendicular alignment to the wind direction. Lenticular clouds can be separated into altocumulus standing lenticularis (ACSL), stratocumulus standing lenticular (SCSL), and cirrocumulus standing lenticular (CCSL). Due to their shape, they have been offered as an explanation for some Unidentified Flying Object (UFO) sightings.


Where stable moist air flows over a mountain or a range of mountains, a series of large-scale standing waves may form on the downwind side. If the temperature at the crest of the wave drops to the dew point, moisture in the air may condense to form lenticular clouds. As the moist air moves back down into the trough of the wave, the cloud may evaporate back into vapor. Under certain conditions, long strings of lenticular clouds can form near the crest of each successive wave, creating a formation known as a "wave cloud." The wave systems cause large vertical air movements and so enough water vapor may condense to produce precipitation. The clouds have been mistaken for UFOs (or "visual cover" for UFOs) because these clouds have a characteristic lens appearance and a smooth saucer-like shape.

Lenticularis often shows iridescence if it is near or in front of the sun. Bright colors (called irisation) are sometimes seen along the edge of lenticular clouds...


Lenticular clouds are usually spotted among mountain ranges...

(Source : Wikipedia)

There are some cases where these clouds have also been known to form where a mountain does not exist, but rather as the result of shear winds created by a front.

(Source : WordPress)

In this case, the front was created by a thick dense "mountain" of cumulus clouds amid a sky filled with higher-level alto and strato clouds...

The rare Flying Saucer in Singapore...


The Cloud Cap

Cap cloud or cloud cap is a stratiform, orographic cloud that hovers above or over an isolated mountain peak, formed by the cooling and condensation of moist air forced up and over the peak and lenticularly shaped by horizontal upper level winds. The cloud appears to remain essentially stationary.

The term is also occasionally used for Pileus (Latin for cap) cloud. Unlike the mountain cap cloud, the pileus is essentially an accessory cloud, that appears as a smooth cap, or hood above a cumulus or cumulonimbus cloud. The cap forms when a humid layer is lifted to its dew point above a rising thermal. This may later penetrate the pileus, which will eventually be absorbed into the main cloud body. Sometimes several layers of pileus form above one another.


The Shadow

A cloud shadow occurring at sunset is formed when light is cast from a low level cloud onto a higher level cloud. During a sunset, the sun's rays will sometimes be blocked by a cumulus cloud below the horizon. Like any shadow, a darkened area will form. These types of cloud shadows are especially dramatic and can appear as darkened rays of light, sometimes referred to as crepuscular rays, as they appear in the same direction as the setting sun.



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The Mushroom That Became A Flying Saucer At Sunset

5:02 AM  , , ,  

Singapore
15 October 2013

An amazing thing happened at sunset today...

First view of this evening's sunset - A remote mushroom cloud with pink, purple and blue streaks  which gradually blossomed into another spiral mushroom cloud...

Doesn't this look like rock formations?

Delicious bubble gum-coloured wisps...

Minutes later, this huge left-angled shadow was formed. How often do you see an upward-casted shadow?

This shadow became a taller and thinner diagonal as the sun sank lower behind this huge cloud mass...

Upon zooming, see the fascinating wind-blown streaks?

This mountain top seems to be forming a cap...

Which morphed into a flying saucer which disappeared into the dark of twilight...



More photos are available on Merlion Wayfarer Goes Green's Picasa at :
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Fair Weather Clouds

1:41 AM  , ,  

Singapore
24 August 2013

Cirrocumulus stratiformis clouds faraway up in the sky which foretell fair weather for the next half day...



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Full Of Fish Scales This Morning

4:51 PM  , ,  

Singapore
24 August 2013

Merlion Wayfarer woke up to a sky full of fish scales this morning...


Cirrocumulus clouds are often found in rows and they look like little puffed-up ripples. Some people think these clouds look like fish scales. The broken or rippled nature of these clouds is caused by air turbulence - It's bad news for anyone flying through them, but great news on the ground because these clouds usually mean that the weather is going to stay the same with no major sudden changes.

True enough...
(Source : NEA)

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Hello Moon Halos!

5:19 PM  , , , , , ,  

Singapore
August 2013

There were two rainbow-tinted rings around the moon last night. - TWO!


The rings that encircled the moon arose from light passing through six-sided ice crystals high in the atmosphere. These ice crystals refract, or bend, light in the same manner that a camera lens bends light. The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear. The ring has a diameter of 22° , and sometimes, a second ring, 44° diameter, forms. 

Thin high cirrus clouds lofting at 20,000 feet or more contain tiny ice crystals that originate from the freezing of super cooled water droplets. These crystals behave like jewels refracting and reflecting in different directions. Cloud crystals are varieties of hexagonal prisms, (6 sides) and range in shapes from long columns to thin plate-like shapes that have different face sizes.

(Source : Keith's Moon Page)

That’s why, like rainbows, halos around the sun - or moon - are personal. Everyone sees their own particular halo, made by their own particular ice crystals, which are different from the ice crystals making the halo of the person standing a short distance away. 

Hmmm that explains why, despite Singapore's small size, 
a moon halo in Changi may not be visible by someone staying in Jurong...
(Source : NEA)

Folklore has it that a ring around the moon signifies bad weather is coming. It is believed that the number of stars within a moon halo indicate the number days before bad weather will arrive. 

Ok, there were zero stars around the two halos.

A while later, the sky completed cleared up and the craters on the moon can be seen clearly.


So how can rings around the moon be a predictor of weather to come? The ice crystals that cover the halo signify high altitude, thin cirrus clouds that normally precede a warm front by one or two days. Typically, a warm front will be associated with a low pressure system which is commonly referred to as a storm.

True enough, this was the sky this morning...


With this weather forecast for the next 12 hours...

(Source : NEA)

More photos are available on Merlion Wayfarer Goes Green's Picasa at :
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Orange Fire In The Sky

4:14 PM  , , ,  

Singapore 
17 August 2013

This morning, the sunlight was golden. The walls of the buildings nearby were awash with slanted yellow rays. In the horizon loomed a strip of cumulonimbus clouds. True enough, by mid-afternoon, a fiery thunderstorm swept across Singapore.

In the evening, the sky was still awash with Stratus and Altocumulus clouds...

In places, thins wisps were being blown away by the strong wind...

At around 1900h, a golden spectrum started spreading across the western sky...

This was sunset yesterday...



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A Red Billowing Thunderhead

9:58 AM  , , , ,  

Singapore
17 July 2013

In a clear sky with some stars and a smattering of alto (mid-level) clouds, the half-moon tonight shone bright and whitish-clear.  


In the distant western sky, there was a huge billowing cloud of at least 6-storeys high. At first glance, it appeared as if a house was on fire. But the ominous red billow stood unchanged for more than half an hour with no visible  flickering light in the horizon.



This is a thunderhead - a towering cumulus cloud.

Rather than spreading out in bands at a fairly narrow range of elevations, like other clouds, cumulus and cumulonimbus clouds rise to dramatic heights, sometimes well above the level of transcontinental jetliner flights.

Cumulus clouds are fair-weather clouds. When they get big enough to produce thunderstorms, they are called cumulonimbus, or thunderheads. These clouds are formed by upwelling plumes of hot air, which produce visible turbulence on their upper surfaces, making them look as though they are boiling. 

The convective airmass is  highly unstable. Just as it takes heat to evaporate water from the surface of the Earth, heat is released when water condenses to form clouds. In thunderheads, this energy can produce short-lived hail, damaging winds, lightning, torrential rain, and sometimes tornadoes. The top of the cloud points in the direction the weather is moving towards.

True enough, this is NEA's weather prediction for the next 12 hours:



More photos are available on Merlion Wayfarer Goes Green's Picasa at :
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Lightning Strikes, Not Once, But Many Times

10:16 PM  , , , ,  

Singapore
June 2013

Merlion Wayfarer was awaken by the bouts of thunder this morning. They came frequently, at a low rumble through the night. Frustrated, she opened the curtains.

This is what she saw...

She was curious - Unlike light, lightning does not travel in a straight line. Instead, it has many branches...

These other branches flashed at the same time as the main strike. Next you notice that the main strike flickers or dims a few more times in a single split second. The branches are actually the step leaders that were connected to the leader that made it to its target.


When the first strike occurs, current flows to neutralize the charge separation. This requires that the current associated with the energy in the other step leaders also flows to the ground. The electrons in the other step leaders, being free to move, flow through the leader to the strike path. So when the strike occurs, the other step leaders are providing current and exhibiting the same heat flash characteristics of the actual strike path. After the original stroke occurs, it is usually followed by a series of secondary strikes. These strikes follow only the path of the main strike; the other step leaders do not participate in this discharge.


It is very possible that the main strike is followed by 30 to 40 secondary strikes. Depending on the time delay between the strikes, it may look like one long-duration main strike, or a main strike followed by other flashes along the path of the main strike. The secondary strike can occur while the flash from the main stroke is still visible. Obviously, this may seem that the main-stroke flash lasted longer than it actually did. Similarly, the secondary strikes may occur after the flash from the main strike ends, making it appear that the main strike is flickering.



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