Archive for the ‘Clouds’ Category

Hole Punch Clouds
January 22, 2017

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Dan Gregoria, NWS San Diego, Huntington Beach, CA

A few years ago I went to a weather conference and one of the more fascinating talks was on Hole Punch Clouds.  Meteorologists know that these “holes” in the clouds are created by airplanes.  The speaker explained that the latest research shows they are created by the propellers of airplanes not engine combustion.

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Courtesy: Sean Browning, KNBC Photographer, Burbank, CA

Here is how they form:

The first requirement is the clouds have to be vertically thin.  The temperatures beneath the wings of a C-130 (seen below) are 14 degrees warmer than the surrounding environment.  This temperature difference and propeller motion creates a dry punch of air falling from the sky evaporating the clouds beneath.  This is always the case but if the clouds are too thick or the plane is above 20,000 feet a hole will not occur.  This is why Hole Punch Clouds are fairly rare to see.  But when you do get to see them, like Saturday, it’s an incredible sight!

c130

If you have pictures to share, I’d love to see them.  Tweet or Facebook me @anthonynbcla

To see other hole punch clouds from Saturday, click here: Hole Punch Clouds

 

It’s Not a UFO, But What Is It?
March 9, 2016

Lenticular_Kim

It’s not a UFO.  These clouds that look like flying saucers are called Lenticular Clouds. They are almost always seen above mountains and form when stable moist air is lifted over the peak and condenses into a lens shape that looks like a UFO. This picture was taken by NBCLA’s own Kim Baldonado in Palm Springs, Calif., on Saturday. 

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Mt. Rainer in Washington sees these unique clouds quiet often.

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This is simply gorgeous!  This was over the Sangre de Cristo mountains in New Mexico.  When they are lined up like this it is called lenticular wave clouds. (Photo by Geraint Smith )

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This is from Lord Howe Island, a volcanic remnant, in the Tasman Sea between Australia and New Zealand.  (Photo by Jan Whiteman)

 

The Mysterous V Cloud Explained
September 30, 2015

VCloud

Courtesy: Jim Walker

Did you look up at the sky on Sunday night? If you did, you were probably looking for the Blood Moon. But many residents in Orange County were treated to more than a Lunar Eclipse Supermoon — they got to witness this V cloud. Many of the people who saw it, took a picture and sent to the NBCLA Facebook page.  Lots of people were creeped out, but there is a scientific explanation.

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I’m sure all of us have seen clouds like the one pictured above. They are called contrails, short for condensation trails. These are artificial clouds that form behind aircraft. They are created by the water vapor in the exhaust of aircraft engines. At high altitudes this water vapor emerges into a cold environment, and the vapor then condenses into tiny water droplets which freeze. Depending on the temperature and humidity at the altitude in which the contrails form, they may be visible for only a few seconds or minutes, or they may persist for hours and spread to be several miles wide.

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Courtesy: @Dalemazing

Now check out this picture. We see the same V cloud or V contrail during the day eight weeks ago in Vancouver, Canada. An airport is on the other side of the mountain. Why the V? At this moment the airplane reaches the altitude where a contrail can form. You have two airplanes coming in for landing at different times, the base of the V is where both planes converge and begin their descent. The timing is perfect.

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Courtesy: @k2rick4

We checked the flight patterns from LAX Sunday night and planes were coming in for landing from the east.  Notice the top part of this picture. It’s the same type of cloud pattern but a different airplane approach. The reason the V in this picture is short is because once the plane reaches a certain altitude where the temperature and humidity will not support cloud formation, the contrail disappears.  The V is the point where the two airplanes at different times come together and begin their descent.

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Here is the flight pattern from Sunday night for LAX, you can clearly see the V pattern as the airplanes come in for landing in red.  The conditions for a contrail to form is between 12,000 and 13,000 feet.

Stealth fighters must be keenly aware of the altitude where a contrail can form. There would be nothing worse than a stealth bomber flying a mission and everyone on the ground sees the jet.  Special thanks to pilot and meteorologist David Biggar for the help.

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Of course, there is always this explanation. Too bad this show got canceled by NBC after one season.

Kelvin-Helmholtz Wave Clouds
November 18, 2013

Hotshots3 Photo by: Kathleen Dimmel, Navasota

These cloud-waves rarely occur because you need almost perfect atmospheric conditions.  Much like ocean waves, the air on the tops of these clouds is moving faster than the bottom of the clouds.  The clouds near the surface are cooler than above and the wind speeds are light, like fog.  Over the low clouds is a warmer and faster-moving layer of air creating the crest, like we see in the ocean.

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Rita Casserly sent in this picture.

 

This is probably the best example from Birmingham, Alabama.

Roll Clouds
November 18, 2013

RollCloud_Houston

It’s called a roll cloud — low, horizontal, tube shaped, and completely detached from the cloud base near it. They are rare to see but when present they are located on the leading edge of a line of thunderstorms, cold fronts or squall lines.

Roll clouds form when cool air sinking from a storm cloud’s downdraft spreads out.  This is called a gust front. This outflow undercuts warm air being drawn into the storm’s updraft. As the cool air lifts the warm moist air water condenses creating this kind of cloud, which rolls with the different winds above and below.

While they look like tornadoes turned sideways, they are not and do not produce tornadoes.

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Photo by: Brian Grimm, Crosby

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Photo by: Vanessa Rich, Vinton, LA

You can e-mail your cloud pictures to: hotshots@click2houston.com

A Finger Cloud
September 18, 2013

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This is a lone a finger cloud. Specifically it’s called an undulatus cloud formed by an atmospheric wave. The cylinder you are seeing is caused by the rising/sinking air around the cloud.
Photo by: Kathi Jacobs, Dacus, Texas

To see other hotshots shown on our morning show click here:

Hotshots

You can e-mail your hotshot pictures to: hotshots@click2houston.com

These are not rainbows
July 11, 2013

Halo_Ric_FennellPhoto by: Ric Fennell

This is called a 22-degree halo and forms on days with cirrus clouds covering the sky.   (The 22-degrees is the radius around the sun.)  These halos aren’t that rare but occur more often in the northern United States and in colder climates.   Cirrus clouds are made of tiny ice crystals and are 20,000-30,000 feet in the sky.  The crystals refract sunlight and bend the tiny crystals into a circle.

Halo_Clay_Spence_BrookshirePhoto by: Clay Spence, Brookshire

Weather folklore states halos foretell of coming rain, but this isn’t true.  With some weather systems cirrus clouds move in ahead of a warm or cold front, but this isn’t always the case either.  They are almost always mistaken as rainbows circling the sun or moon but aren’t because these halos form on dry days.   Cirrus clouds do not produce rain.  They are a treat to see.

Halo_Emily_GibsonThis a rare double 22-degree halo.  Photo by: Emily Gibson

First Tornado Picture
January 31, 2012

 

Here is a good article about this photo and where it was taken.

To view past weather quiz answers click here:

Past Weather Quiz Answers

Hole Punch Clouds
December 21, 2011

 

Earlier this year I went to a weather conference and one of the talks was on hole punch clouds.  The latest research shows they are not created by engine combustion at all.  The first requirement is the clouds have to be vertically thin.  Researchers then discovered that the clouds usually form beneath C-130 planes (shown below).  Beneath the wings of these planes temperatures were around 14 degrees warmer than the rest of the plane and surrounding environment.  This temperature difference created a dry punch of air falling from the sky evaporating the clouds beneath.            

On a side note, a big thanks to Stephen Kornblitt who took this picture and sent it to Frank Billingsley.  A lot of people said it looked photo shopped but our engineers at the station said it was authentic.  Most hole punch clouds are circular.  This one is unique because it looks like an outline of a plane or the state of Texas. 

To view past weather quiz answers click here:

Past Weather Quiz Answers

Cloud Streets
November 7, 2011

 

Howard Stout took this picture at his home in Santa Fe. 

Here is another view of cloud streets from space. 

When the low-level air begins to rise, clouds can form.  Some days there is a layer of stable air above, and that limits the vertical extent of the convection.  If the wind is fairly uniform the clouds can form “streets”.  You’ll get parallel lines of clouds alternating with the clear skies.  These gaps are caused by the rising/sinking air produced by the rotating horizontal cylinders in the atmosphere. 

To view past weather quiz answers click here:

Past Weather Quiz Answers

A Sun Pillar
August 29, 2011

 

 

 

 When the atmosphere is cold, ice sometimes forms flat six-sided crystals as it falls from high-level clouds. Air resistance then causes these crystals to lie nearly flat much of the time as they flutter to the ground. If viewed toward a rising or setting Sun, these flat crystals will reflect sunlight and create an unusual column of light — a sun pillar as seen above.

 

To view other sun pillars click here:

Sun Pillars

To view past weather quiz answers click here:

Past Weather Quiz Answers