Topic: NSW/QLD Showers/Storms 26-30 Sep 2007

[Michael Bath]

GFS maintains the potential for thunderstorms in NE NSW and SE QLD Thursday. Today's 00z run actually improves the instability in parts and reduces the concern of too much mid level cloud - though will see what the satpics look like in the morning. Surface moisture looks to be ok around the Northern Rivers and the Greater Brisbane area.

NSW BoM have had no mention of storms in any of their NE NSW district forecasts this week, though the QLD BoM have for SE QLD districts.

regards, Michael

[Shaun Galman]

Hi guys,
Looks like a bit of storm development out behind Bourke, also a cell to the NW of us that looks like it's tracking towards us though they look like fairly short lived cells from the lacking moisture in the atmosphere?

We have a thick covering of mid level cumulus and some nice dark bases forming here and there.

I'm not willing to make any form of prediction for us here tonight as I seem to jinx myself everytime lol

Cheers and take care.
Shauno

[Shaun Galman]

Hi guys,
Well we just had a small squally cell pass over us. It was sparsely active and a little dangerous to photograph due to the fast (and unpredictable) cg that were seemingly everywhere and nowhere? I have a few shots here to show but couldn't catch any lightning, so I do apologise for that. Still waiting for nightfall and the next line of activity to pass over us!


Taken on the western side of town as the cells approached us.

Taken 1km from town looking towards the West, there were quite a few fast cg around at this point so I didn't hang around long!

Same area as picture above but looking North across the same cell.
I do have a small amount of video to go through and I will post anything that seems worthy!
Cheers guys.
Shauno

[Michael Bath]

Was just about to ask if you got anything decent there Shauno !  Radar and lightning tracker looked nice

regards, Michael

[Steven]

That was a nice little squall line for outback Queensland! but at any rate, that trough is coming through fast so I'd say development is likely to occur early in the afternoon. I'd even wouldn't rule out a possibly of a squall line developing based on what we saw today with the Warrego squal line. Glad to see the new Gympie radar (which recently got a much needed upgrade) will be tested for tomorrows event.

[Michael Bath]

Looking quite good for some storms today in parts of NE NSW and SE QLD. Rain band is clearing out now and dew points are high across all of NE NSW. Be interesting to see the soundings shortly to check the depth of the surface moisture. The wind profile is not ideal and will mean storms are going to quickly head out to sea.

[Steven]

Pretty disappointing throughout, only managed a few isolated (but intense) cells south of Brisbane, in fact quite intense for large hail, and I'm pretty sure there was too when there was brown on radar. But other than that, I don't much see another chance for more storms until the next time. although I did hear perhaps a slim chance for the weekend I am not sold.

[Jimmy Deguara]

Hi Steven,

I would not say I would be disappointed at all. The situation was marginal but the trajectory indicated there was just enough in the atmosphere to produce one or two cells. That supercell was quite nice actually.

Regards,

Jimmy Deguara

[Steven]

I know, it was disappointing that I didn't see it though.

[Jimmy Deguara]

Steven,

There will be a lot of disappointments. But look at it on the bright side - somebody did and took pictures and showed a little of what the structure had.

Still let's look on the scientific side as that is what I would like to see discussed on this forum. It was not what we call a massive supercell. I just think it put up a couple of very strong pulse updrafts that allowed for a brief organised structure which is awesome.

Regards,

Jimmy Deguara

[Michael Bath]

Hi all,

Certainly a nice cell in Southeast Queensland yesterday. I could see the supercell from here, but only just because of the horrid haze.

The Doppler picks up the track of the cells pretty well:



I've done up two interactive radar loops - the 64km one involved screen dumps as there are still no auto archives of that radar. Will do up some Doppler images soon.

Mt Staplyton 128km

Mt Staplyton 64km

MB

[Steven]

Very nice loops there Michael, although I've noticed you don't animate them any more with a GIF animator.

Jimmy, the bright side is that the storm was strong throughout it's course, the dark side is, only a few isolated cells got going, but when you have been storm deprived for so long, generally even average storms are good enough, but don't take this the wrong way though, I am impressed at the photos though.

[Michael Bath]

Steven - it's much better having these interactive radar loops so you can stop/start/speed up etc as you wish.

Here's my view of the storm at 4.42pm and 5.13pm:





Satpic close to the peak of the storm (going by radar) at 4.30pm local:



Some nice speed shear on the Brisbane soundings - even up to 25 knots at 850 hPa.
  Brisbane 00z

Brisbane 12z

I replotted GFS and it gives some clues as to why the activity was fairly isolated - with none in the Northern Rivers apart from some isolated congestus showers: the moisture was much better over the Brisbane Valley up to the eastern Downs.

Thursday 27/09/2007 06z

Instability: CAPE / Lifted Index

Relative Humidity: 0300 / 0500 / 0600 / 0700 / 0850 / 1000

Temperature: 0300 / 0500 / 0700 /  0850 / 1000

Winds (knots): 0200 / 0300 / 0500 / 0600 / 0700 / 0850 / 0925 / 1000


And finally the Doppler images I saved ...

http://australiasevereweather.com/storm_news/2007/radar/20070927d/mt_stapylton_doppler.htm

regards, Michael

[David C]

Good to see the first solid storm of spring.

Do the BoM provide actual velocity data on request, if asked, or, is there a simple algorithm we could plug data in to so as to get an estimate? Just eyeballing the storm motion, say ~40-45km/h, together with the in- and out- bounds on that doppler scan at the time the storm was probably most intense (generally sw to se of Boonah), then I'd guesstimate that the rotational velocities are only in the order of 30-60km/h (~15-30 knots) at a range of ~ 40 nm. In other-meteorological words, and putting this into perspective, this was a rather weak mesocyclone and the PPI scans reflect this with a somewhat brief duration of nice structure.  Any photos of the base anywhere in/around Boonah?

Good to see the BoM excited though and hopefully this is the start of a long bust severe weather season

[Shaun Galman]

Hi guys,
Great structure in those shots Michael! Pretty textbook looking cells, crisp anvil and what looks like a nice flanking line! Shame about the haze spoiling your view, but there will be others on more clearer days, not too far away

I had no luck with the second line on the 26th at around 9:30pm. It was just the odd cloud burst here and there, no lightning as far as I could tell?

If it had of waited another hour or so I would have some nicer CG shots for you all (but we can't win 'em all?). I'm eagerly awaiting the next broad trough now as the temps are on the rise again into the 30+ range and it would be great to see the moisture levels do the same! Definitely nice to see some decent storms brewing around the place!

(Thanks kindly for sorting those images also Michael!)
Take care
Shauno