6th March 2017

Had another great little chase into the wheatbelt this afternoon. I could see cumulus towers popping up out towards Northam, so I headed to a great spot that I like near Meckering that has good views to the east. It was a hot day (37°C+) and the flies were out in swarms. This is not unusual for this time of the year in Australia, but it takes some getting used to when you have lived in the city for a few years.

It was immediately clear that this setup was going to produce something spectacular, but I wasn’t quite expecting it to be this good.

There was a line of storms popping up that stretched from the north west to the south east (left to right in the following pano).

As impressive as the main cell in front of me was, it was the small cell to the right that caught my attention. It shot up rapidly and within an hour had became one of the most spectacular anvils I have ever seen. The following sequence of photos highlights the growth of this cell.

At this point, I made the call to move further east towards Cunderdin to follow this cell in the hope that it might became lightning active after sunset. By then, it had grown into a very large thunderstorm and the setting sun lit up the top in an impressive display of colour.

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There was a fair bit of lighting in this cell, but by now it was moving away to the SE and I didn’t really plan to follow it that far.

Behind me, another thunderstorm was making its way south and this one was very lightning active, but the rain and dust obscured most of it. I did manage to get a shot of some mammatus that had formed.

As darkness fell (and a gazillion mosquitoes came out) I decided to head back to the Great Eastern Highway to find a better location to try and capture some lighting shots. I finally found a spot just west of Cunderdin and set up the camera. The decaying storm that was approaching still had plenty of energy and the gust front pushing out in front of it made it hard to keep the camera and tripod steady. Even so, I managed a few photos as the storm headed my way.

Even though this chase was only a few hours long (380km round trip) I really enjoyed it. The cloud structures I saw were truly amazing. So here is one more of that anvil.

Be sure to check out my photography page at mattfrickerphotography.com where you can  purchase many of my weather images. Enjoy.

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Virga

virga02Virga is an observable streak or shaft of precipitation that falls from a cloud but evaporates  before reaching the ground. At high altitudes the precipitation falls mainly as ice crystals before melting and finally evaporating; this is often due to compressional heating, because the air pressure increases closer to the ground.

Daniel Pardini copy  Daniel PardiniImage credit: ©Daniel Pardini – The setting sun lights up virga over the northern suburbs of Perth, Dec 2015.

Virga can cause varying weather effects, because as rain is changed from liquid to vapour, it removes heat from the air. In some instances, these pockets of colder air can descend rapidly, creating a dry microburst which can be extremely hazardous to aviation.

Virga also has a role in seeding storm cells whereby small particles from one cloud are blown into neighbouring supersaturated air and act as nucleation particles for the next thunderhead cloud to begin forming. When virga is occurring, you will often see precipitation on the rain radar, but the ground will be dry.

virga01Virga from a decaying thunderstorm in the wheatbelt region of Western Australia.

This article is reproduced with permission and adapted under the Creative Commons Attribution-ShareAlike Licence. http://creativecommons.org/licenses/by-sa/3.0/
Article source: https://en.wikipedia.org/wiki/Virga

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Pyrocumulus Clouds

A pyrocumulus cloud is produced by the intense heating of the air from the earths surface. The intense heat induces convection, which causes the air mass above the heat source to rise. As the air rises it expands and cools. If the water content in the rising air mass cools to the dew-point temperature in the atmosphere around it (the temperature at which condensation forms) then cloud formation occurs. This is the same mechanism that causes thunderstorms to form on a hot day.
Amery Drage 01Image credit: ©Amery Drage. Large pyrocumulus cloud from a fire in the Kalbarri National Park, 13th March 2014. The base of this fire is between 50-60km away from the photographer. Notice how the winds at a higher altitude are pushing the top of the cloud over to the right.

Jordan Cantelo 01Image credit: ©Jordan Cantelo. Arial view of the Boddington fire, Feb 2015.

Phenomena such as volcanic eruptions, forest fires, and occasionally industrial activities can form of this type of cloud. The detonation of a nuclear weapon in the atmosphere will also produce a pyrocumulus, in the form of a mushroom cloud. Condensation of the moisture already present in the atmosphere, as well as moisture evaporated from burnt vegetation or volcanic steam, occurs readily on the particles of ash in the cloud. In reality, a pyrocumulus cloud is made up of smoke, ash and condensed water vapour. This is why they always have a greyish to brownish colour, with the tops looking more cloud like than the smoke plume closer to the ground.
Brayden Marshall 01Image credit: ©Brayden Marshall. View of the Boddington fire from the Perth metro area. The base of this fire is approximately 120km away from the photographers location.

craig eccles 01Image credit: ©Craig Eccles. Small pyrocumulus cloud starting to form. Notice how the majority of the smoke is blown to the right but the hot air rising straight up is forming a cloud as water vapour condenses.

Pyrocumulus clouds often contain strong updrafts, which can cause strong wind gusts at the surface. This effect can make an already dangerous fire even more so. As the hot air mass rises, fresh air is pulled into the base. Even a relatively small fire can create it’s own in-draft, which further fuels the fires capacity to burn.  A large pyrocumulus, particularly one associated with a volcanic eruption, may also produce lightning. A pyrocumulus which produces lightning is usually called a pyrocumulonimbus cloud, but not all pyrocumulonimbus clouds produce lightning.

There have also been many recorded examples of pyrocumulonimbus clouds producing rain. There are even a few examples where pyrocumulonimbus clouds, caused by forest fires, actually quenched the fire that spawned them.

Sam Kaye 01Image credit: ©Sam Kaye – Sam posted this photo into PWL on 3rd Feb 2015. It shows the pyrocumulus cloud from the fire near Boddington. Notice how the smoke turns to cloud at about the same altitude and the conventional clouds.

This article is reproduced and adapted with permission under the Creative Commons Attribution-ShareAlike Licence. http://creativecommons.org/licenses/by-sa/3.0/

Article source: http://en.wikipedia.org/wiki/Pyrocumulus_cloud

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Cirrus Vertebratus

A type of cirrus cloud resembling a spinal column or fish skeleton, hence the Latin vertebratus for vertebrae-like.
Cirrus_vertebratus
Image credit: Wikipedia, © used with permission under creative commons license.

These clouds form at very high altitudes (usually between 6000m and 14000m) and often indicate that stormy weather is coming. They usually start out as a smooth band of ice crystals that is then blown by crosswinds to create the fine streaks to either side of the central column. They can be straight or curved, like the one I saw today (in the image below, which is a very poor quality phone image, sorry)IMG_3161Image credit: ©PWL/Matt Fricker taken on 16 Nov 2014

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