Topic: VIC/SA/NSW Severe Thunderstorms 26 - 27 November 2009

[Macca]

Great photos guys.  

Jimmy - glad you finally got out into some action!  Some of the structure in your photos is pretty nice - amazing what some shear will do hey!

I also note that Michael Thompson was out chasing in a simliar area yesterday and got some pretty nice photos too.  One in particular is a very nice photo of a base which Michael said was rotating nicely!  Good stuff.



And on today...for Victoria...

I reckon today looks pretty good - especially in western Victoria.  I like the area around Nhill (not much farther as road options deteriorate rapidly from here until you are into SA - patience will be required if waiting at Nhill).

PRO's

- Warm air at 850mb pushing into the area (rest of Vic is relatively cool and it'll need to get into the low 30's to get anything dcent happening). 
- Nice shear.  25knts NNW'ly at 850mb, 50knts NW'ly at 500mb, 80knt jet. 
- Instability is pretty decent (-4 to -5 LI's) and there will be added lift from the approaching upper trough.

CON's

- Potential for dry air intruding above the surface (with the warm air at 850mb comes drier air).  This is evident with the DP's in the west being in the 12-14C range.
- Warm 'slot' at around 650mb could result in inhibited updraft growth at that level which may lead to mid-level cloudiness.

I reckon the pro's far outwiegh the cons and I'd give it a go if I was in Melbourne/Vic today.  Would've posted thse thoughts earlier but I'm 3 hours behind being in Jakarta atm.

Potential for isolated storms initially but forming into line/s later (eventually moving through Central Vic pretty late).  Damaging winds will be most likely given the temp/DP spreads and shear, but large hail is definitely not out of the question (4-5cm possible in the strongest storm).  Flash flooding also a possibility but given the speed storms will be moving, I'd say its less likely.

Macca (in Jakarta)

Macca (in Jakarta)

[Macca]

Still pretty happy with my target of Nhill although you could now pretty much pick anywhere between Mildura and Warnambool and you'll probably get something.  

The most lightning active storms are about 100km NW and NNW of Nhill heading SE (generally) and moving at a fair clip so I'd dare say that just on sunset I would be in for some action. Oh wait...its late November in western Vic so probably light until 8:30pm!  So daylight action it is!!  (It would've been nigh on impossible to stop me from going further W earlier on thou...hehe).

Macca (watching from Jakarta...)

[Macca]

WHOA! 47knts (87km/h) and 12mm in 9 minutes at Nhill. Nailed! And from what I can see, the main core of the storm passed just to the north of there! Looks like its going to pass just N of Horsham too but might just clip Longrenong - will be interesting to see what the obs there show in the next little while. 

Edenhope also recorded a 40knt gust as the line of storms went through there.

Renmark (in SA) scored 91km/h!

 

Macca

[Peter J]

John,

Thanks for clearing that one up... I wasn't sure about the storm characteristics, but it sure was a mean storm. It did do quite a bit of damage around Doncaster and Nunawading, as well as Rowville (where a 16 year old was struck by lightning). It was intense.

My brother, who lives in Wodonga, watched a spectacular light show from cells near his place last night, and it was one of his friends who tracked a confirmed gustnado near Benalla.

I was surprised by the rotation in the Doncaster/Box Hill storm that I observed in Box Hill (at my dad's place). And even though it was a meaner storm the north and east of my location, it did get a little wild here, but not as bad as the locales mentioned above.  The greenness gave it a meaner look, and was almost similar to the Giant hail storm that I witnessed in Croydon back in 1983, just didn't spit out much hail as it passed. But it was travelling at about 50-60kph as it passed over.

Certainly was a good afternoon/night for storm observations from inside the house.

Heading home soon to observe and detail the damage (if I can find any) on the way...

Big Pete
(can't believe I left my Kodak C813 at home... Bugger!!)

[Michael Thompson]

Good to see that some other chasers scored Thursday's southern tablelands storms.

Chances are that Jimmy and I passed as we were on similar storms at stages.

Day started possibly on the same initial storm as Jimmy, I was about 5kms south of Berrima and followed this storm to Bundanoon. Near Wingello another storm developed to the west



I then headed further south to Bungonia where there was further weak cells. Fortunately I started heading back to Goulburn and picked up some lovely development right in town almost.

As Harley mentioned this cell appeared to appreciate the slug of moisture from the weaker storm to the east - I have rarely seen such rapid development





This video should show some rotation:

Goulburn Severe Storm - 26th Nov 2009

This pic below is of the cell Jimmy was on near Marulan, evident hail shafts in picture.



I managed to actually catch up with this cell and saw some hail along the road along with the usual mess of traffic.

At Canyonleigh I finally managed to hook onto the little squall as well, so a great day !

[Harley Pearman]

Goulburn thunderstorm 26/11/2009

Michael, thank you for the additional photos of the Goulburn storm. Your photos show the storm after it had passed over me. I watched the storm develop to the north west of me. What amazed me is that initially the storm was weak (First photo). I did not think much of it at first but I decided to stay at the lookout to see if it would do anything. Approaching Goulburn the thunderstorm rapidly intensified (Second photo) and it happened in a matter of minutes. The third photo provided shows what it was like inside it moments before the hail.

Prior to this storm, I was experiencing outflow or strong gusty easterly winds from the previous thunderstorm and it intensified from that.

Harley Pearman

[Michael Thompson]

Goulburn thunderstorm 26/11/2009



Prior to this storm, I was experiencing outflow or strong gusty easterly winds from the previous thunderstorm and it intensified from that.

Harley Pearman

Definitely the key element Harley, I was coming up from Windellema when I noticed these winds. I stopped and ran some footage of that weak storm over the range east of Goulburn, I took some observations and noted that DP's had climbed to a staggering 19C, this was on a Kestral - I realise that the DP's even 10ft higher would have much lower as there was evaporating puddles everywhere. However the other key element was that it was not what you would call 'cold' outflow, in the distance from that weaker storm the outflow temperature had climbed back up the mid- - high 20C's.

We tried to outrun the storm SE back towards Windellema, we got stuck behind a 'hillbilly' truck as Steve called it. It took a good 15-20kms to just get far enough in front to take 10 secs of video and snap off 2 pics. This is what the line looked like SE of Goulburn.



We allowed the storm to overtake us and simply had to pull over as it became a total whiteout - believe me I do not readily pull over !

[vrondes]

Excellent variety of storm structure in your photos Jimmy , Michael and Harley. Always a pleasure to see a storm evolve  and not be obscured by urban structures or close trees. Even that Richmond cell had some structure only just glimpsed in the following frame, again well done to all on their reports and photos,Cheers, Con.

[Jimmy Deguara]

Hi,

Certainly shows some structure there Con - again I was too close to note the whole storm scale structure.

In relation to the Mittagong event on the 26th November 2009, I decided to upload a video of the timelapse at 40x speed.

http://www.australiasevereweather.com/video/flash_video/2009/timelapse_mittagong_supercell_november_26_2009.flv

Regards,

Jimmy Deguara