Severe Weather 2012 / 2013 Season

What a crazy mixed-up day today turned out to be.

Instability was off the charts but wind shear was almost non-existant. This resulted in Top End style storms whose impressive updrafts explode and utilise all the available instability, but then quickly collapse in on themselves because there is little inflow or wind to push them into fresh new unstable air.

Steering winds were a bit mixed up too, pushing these storms all over the place making them tricky to chase.

The initial target was around Maryvale. I figured stuff would fire slightly S first along a NW / SE surface trough. Dave Smith and Cam were in tow today and we stopped at Freestone (just NE of Warwick) and sky-gazed for ages watching towers billow up then down, waiting for something interesting to happen. A hefty cap would keep convection at bay until there was enough heat to punch through it, so I figured it was just a waiting game.

 

A storm had taken off near Yarraman, but that was way too far N to bother with. An updraft finally broke through around 1pm 50kms S of Killarney:

 

Here's a timelapse:

A number of small cells along that part of the trough took off, hit the troposphere creating a small anvil, then died.

 

A healthy updraft to our NNE was a bit of a concern as I was worried we might have driven too far W:

 

This is where things got tricky. The GFS forecast model showed a surface trough well into the Darling Downs further inland. Chasing is awesome in that area because of the great views and this is where I was hoping storms would fire. So I was torn between hanging around and waiting for something better from that area, or getting in front of this new updraft to the NNE. My desire for storms to occur in a particular area has always beared little relationship with where storms decide they actually want to fire so I put my selfish thoughts aside and stuck with what we could see.

So we did the hideous drive back over the range and waited at Aratula and watched this cell, then several others, die as they came off the range. You could mark the range on the weather radar yesterday as cells seemed too shy to leave it.

More waiting and wondering. The Yarraman storm had not only persisted but was building and tracking ESE. All of our local small-fry storms were not delivering the goods so we shot back up N along the Cunningham Hwy towards Marburg. This storm, now near Gatton, produced a black core on radar.

We finally stopped just E of Marburg where there finally appeared to be a bit of organisation in the storm, as well as some mammatus:

 

Steering winds seemed a little odd with the radar showing two nearby cells going in almost opposite directions, about to collide. The S storm finally showed a hint of structure or developing shelf cloud so I took off SE back to Walloon, which felt weird. Storms in SE Qld generally produce their best structure on their N side so it felt counter-intuitive again to be heading SE, but today was a weird day.

         

With light rain falling E ahead of the main part of the storm, I continued S to stay dry, which turned out to be a good move as this N cell weakened and some near development was occuring the SW. Dave and Cam, however, were in their own car and took themselves back E along the Warrego Hwy and then called it quits, which is a pity as the best part of this day was only just beginning.

I stopped at Mutdapilly for a view SW as lightning started to pick up.

     

I was about to head back NE as that is the direction most storms here move, but the radar showed a black line forming and tracking ESE. Hope for today was renewed as I ignored my instinct to head NE and continued SE towards Boonah.

Lightning was now quite regular, outflow winds strong, and large rain drops meant I couldn't hang around any one spot for long as I wondered whether I would make it to the Boonah-Beaudesert connection road before being swamped.

       

I made it to the Boonah-Beaudesert Rd in the nick of time as the sky started to get angry.

 

The storm was nipping at my heels and it was an exciting drive trying to stay ahead of it. I stopped again closer to Beaudesert:

   

A new cell had popped up just to the SW and was heading NE towards me and eventually merged into the storm I was fleeing. Chasing E of Beaudesert gets tricky because of the ranges around Mt Tamborine. The radar showed this storm to be weakening, with new activity strengthening over the border ranges to the S, so I did something I don't often do and chose to let this storm pass over me. It seemed to split and break up around Beaudesert sparing me of much rain, which was handy.

   

Lightning activity was ramping up to the S, but there were also some more clearly defined CGs (cloud-to-ground lightning) landing more to the W. This new system was heading NE towards me and driving W would mean possibly not making it back to Boonah before the storm's arrival. Once committing to Boonah, you must pretty much go the whole way because of a lack of good views in between.

Considering this, I took off S towards Rathdowney to be closer to the lightning. I didn't get far as my own CGs started landing closer than expected so I stopped just S of Beaudesert:

     

Local CGs then dropped off and started to pick up further W again, so I did a 180 and backtracked towards Boonah. Again, I only made it about 3kms W of Beaudesert before forks started landing close by. Luckily, they made themselves apparent before I hit the range.

     

Finally, this storm was producing the CGs I was hoping for. In the inky blackness, the sudden lightning strikes were incredibly bright as they pierced their veins through the night air.

           

Eventually, the rain arrived and I retreated back to Beaudesert:

 

Again, the rain increased and I headed N up the My Lindesay Hwy stopping one last time at Woodhill:

     

The storm was turning into a large rainy mess, so despite the occasional flash, I headed home.


Brisbane 128km radar loop 11am-5am

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