Topic: Late Winter Thunderstorms NSW / SE QLD : 11-13 August 2009

[Colin Maitland]

You could almost classify them as dry thunderstorms, at Bracken Ridge we had about a dozen drops of rain, then a fantastic lightning show from 6:45 - 8:30 pm. I took about 120 photos, but only 2 turned out . A very frustrating thing to do. I missed some absolutely brilliant vertical bolts trying to set the camera. I honestly think you need a SLR camera with a remote to keep your finger off the camera to avoid shakes.

[Kristy Norman]

Looks like a nice early start and loving the photos, especially the offshore storm. Beautiful colours! I can't wait for it to warm up and get unstable down here! What camera are you currently using Coltan?

[Chris.]

Warwick Qld. 12th August 2009

Hi everyone, great day up here yesterday! Started with a small cell around 2.30 pm and continued to build over town until it left here just on dark. Some rain for the farmers and pea size hail from one of the cells that formed. There were about 4 or 5 that visibly came together just on dark and I manged to get into a position to photograph the width of it as it headed out over the range.

These are posted in order and taken within a 3 hour period as the storm built itself up and left. Most are black and white because I had no foreground light, hope that is permitted.

This was the first sign something was brewing.

Regards,
Chris.

[Steven]

Some activity about the hinterland of the Sunshine Coast, but the bulk of it is moving rapidly toward the coast. Quite a few deep rumbles about. No rain as of yet.

[Colin Maitland]

Watched that one go to the north of us. Tried to get some photos. Some nice lightning again.

[Antonio (stormboy)]

Wow I did not think that there were meant to be more storms this evening in se QLD. And yes another day where we could have another thunderstorm has been confirmed.

Monday Isolated afternoon showers and thunderstorms. Very warm northwest winds before a southeasterly change.

i am also attaching a chart showing the cape on Monday i do not know anything about these charts but here it is.

[Antonio (stormboy)]

the radar below shows the development of the few storm cells in SE QLD this afternoon. the first cell starts at 4:18pm it also shows the end of yesterdays cells

See : 128km Radar Loop for Brisbane, 10:00 12/08/2009 to 10:00 13/08/2009 UTC

[Shaun Galman]

Some seriously nice photos guys!

Kane: Those are really spectacular sunset lightning photos! I'd be overjoyed to have taken those! :D

Chris.: Love the contrast in those B&W photos! I've never really thought of doing any B&W weather work before?

Good to see some great structure about. Did the storms pack much of a punch? They looked okay on radar, nice red core's etc.
It's getting me all excited now lol. It has almost diminished my SDS

Take it easy.
Shauno 

[Michael Bath]

Shauno - there was hail reported from various cells but the radar was certainly over-cooking the situation. The largest hail report I've heard of is 2cm diameter but it was mostly small stuff.

The web version radar is misleading in these sort of setups where the storms are high based and low topped in quite cold conditions. A lot of the precip has to fall through a rather dry layer so what you get at the surface does not match what the radar indicates.

MB

[Chris.]

Hey thanks Shauno. The conversion, in my opinion, shows the depth of tones in the cloud. Provided you don't overdo contrast and you capture the detail in your exposure, you see even more detail with the black and white. There is an option in photoshop to convert to black and white using channels, rather than a desaturated image.

The secret is to achieve the 'tonal range' in the conversion. Then you see the detail. Thanks again mate!

[Mike]

Nice latter stage images there, Chris.  The B&W do look nice and for me at least they do give nice contrasts as opposed to the color variety!  MB, so the reflectivity of the radar image gives a false view of what is actually hitting the ground?  How interesting.  I guess in reality it is in fact detecting what's in the storm and not recording what's on the ground per se.  This may be something worth experimenting with whilst out chasing.

[Colin Maitland]

I was under the impression that the radar detects the estimated rainfall intensity within the cloud not what is falling,  BOM states regarding radar readings "that The radar reflectivity is strongly dependent on the diameter of raindrops in the cloud not the amount of rain drops and therefore rainfall rates."

I think what we saw in those storms can be found in an article called Dry lightning and Dry Microbursts.
  http://www.weather.com/blog/weather/8_13021.html

Due to SEQ heating up, I thought we would see some early storms build, but due to the low humidity at this time of year I didnt expect much rainfall, thus leading to virga in some areas and just a few drops or a light shower in others places, egs Dayboro. Usually we have brilliant lightning storms late August very early September.

I thought I would clarrify "Virga in some areas and a few drops in others," this was also due to the fact that we had several storms cells build through out the afternoon, some had no rainfall while others just a few drops or a light shower.

Cheers

Col

[Shaun Galman]

Hi guys,

Thanks very much for the info all!
It interesting that I've never really thought of the radar in that respect? Always just assumed it was an overall grab (if you will) of current rainfall conditions and severity, much as Mike said above. I will now pay attention to any similarities that I witness during a weather event, though we are right on the outer edge of the Moree radar which is not too helpful for us.

Really wish the bureau would place an installation out near Bourke or Tibooburra at some point.

I wonder if satellites are capable of piercing into clouds and detecting rain like the ground based installations do? Surely the capabilities are there. It's got to be more handy and reliable than current limited ground based technology. The Moree radar goes missing every time they have a storm overhead lol. That can be frustrating when I notice a large cell tracking towards us on the edge of the radar range then I lose all distance and arrival time info.

Kindest regards,
Shauno     

[Mike]

That's why we're storm chasers and not radar chasers, Shauno!  

Interpreting radar is difficult at the best of times and we can only go on what BoM supply.  The advantage of having Doppler at least nowadays for most Oz regions is that we can chase by wind profiles as well as viewing the standard radar to assist...but there's nothing like ending up with a bust because we were on the wrong side of the storm to begin with!