Afternoon & Evening Brisbane Storms
Produce Nice Gust Fronts

February 22, 2002

Today was somewhat unusual.  On paper, it looked very marginal, LIs around –1 to –2, with very warm upper levels.  The wind shear wasn’t crash hot (although not absolutely hopeless either).  Really, it looked marginal at best.  But the night before, I ended up lying outside on the ground with my dog – and it felt so much like a storm night!  The gut said something would happen, while the brain said no.  In the end, it ended up being even better than I imagined!

It took a while for things to get going – some CJs developed on the border ranges, I kept an eye on them on MB’s webcam.  They eventually started to precip and a cluster of them started moving towards the NE.  They were forming just ahead of a weak SE change, and pulsing into the yellow and green.  I had to work during the afternoon, so was unable to chase – but I couldn’t see much development from where I was.  Even when a cell pulsed into the pink I still couldn’t see much!  It looked like the Gold Coast would get a storm, but as for anywhere further north of that – perhaps not too good.  But the weak line of storms appeared to interact with the seabreeze front and developed strongly on its NW side.  In between work, I ducked outside to have a look and nearly fell over when I saw a strong line of updrafts developing!  Needless to say, I tried to finish as quickly as I could – updrafts were exploding on the NE side of the line!  The line was moving slowly though – but it was a fairly solid line of yellow, green and some pink on radar.

When I finished work, I shot out to a quick lookout to get a proper view of the storm.  The front had weakened a little, and I debated with myself whether to stay where I was, or head a little closer. 

I was in a good position to watch it where I was, but I didn’t want the line to collapse before it got to me (it had a good 30mins to get to me even though it was only about 20km away).  I headed south along Creek Rd, and then onto Newman Rd and quickly came into view of a nice little gust front. 

It wasn’t too bad for a small storm and a slow moving one at that!  I found a quick little road and took a few photos and some more video.  It was in a hilly part of the southside, so it made it difficult.  But I was near Wishart so decided to go towards there and look south on a hill (the main part of Wishart is on the southern side of a large hill). 

I stayed there for a while before deciding (perhaps a mistake), to get closer.  Unfortunately, the storm had just gone over the M1.  And that had caused some accidents due to the torrential rain, and the M1/M3/M4 intersection was totally shot!  So I got stuck in there unfortunately…and by the time I got out of the jam, the storm had mostly moved out to sea.  I normally cause these situations a "storm jam" - they happen frequently when a heavy storm goes over a major road.

I got back home and noticed some more storms forming on the Cunningham Ranges.  I decided to wait a little and see what they did before heading out.  The low levels at the surface were moist (DPs 21-23), but the levels just above that dried out rapidly.  The other reason was I had to take the M4 to get onto the M2…and to do that, I would have to face the M1/M3/M4 interchange and wanted to let the traffic die down a little.  But the storm continued and it was actually strengthening!  I decided to eventually head out again…it was slow on the interchange, but once I got past that it was smooth sailing.  The M2 was heavy, but the usual Brisbane motorway traffic (everyone doing 100km/h with about half a car length in front of you of space!)  I quickly got onto the Cunningham Hwy and caught a glimpse of the storm at last.  There was a lot of other cloud around so it was difficult to see, and this storm wasn’t overly high either.  I could see the guster just to the south, it was looking quite nice! 

Unfortunately, I wasn’t able to go to my usual advantage point at Amberley as that was too far south.  Instead I had to accommodate a lesser view further north.  I took the Swanbank offramp and then pottered around trying to find a view.  It was difficult to find a view – trees, houses and even the big power station in the way!  But I was able to jockey around the area and take some video footage…although unfortunately I wasn’t able to take any photos.  Which was a shame, because the laminar banding on the gust front was really looking great!!!

The storm wasn’t moving overly quickly, but eventually it was time for me to move.  I had to go further NE to stay ahead of the storm.  At the same time, the lightning was increasing in frequency – from about once every 5-10 seconds to once every 1-2 seconds!  The static discharges was reflecting this nicely.  I headed back onto the onramp – and soon discovered that the Cunningham Hwy onramp at Swanbank to the north would have been a great place to stop!  But oh well!  Meanwhile, I caught a glimpse of what I first thought was a deeply descended narrow lowering…but soon dismissed it as smoke.  The fire was actually near my parents’ farm, the dry land allowing for lightning to start a fire near Hiddenvale.

With the increase of lightning I decided to meet a friend of mine at Sunnybank.  It took me a while to get there, and unfortunately the storm had weakened when I got there!  A shame, as we were in good position to see the lightning about 10km to our west.  I did however get to witness a few nice CGs while driving there!  We then decided to go to Mt Gravatt and look to the north, but the storm had weakened considerably and by a bit after 8pm we both went home, and I grabbed some dinner on the way back.

I was surprised to get an email from an ASWA member about 50 cent piece size hail at his house due to the warm upper levels.  I was also surprised to see on the news the following day about how trees were brought down on top of houses in some suburbs!  Moggil received 50mm in around 20-30 minutes, the main severe weather threat I thought of (ie heavy rain!)  But this storm appeared to also interact with the seabreeze front and convergence line, giving it additional lift and strength allowing it to become severe!

All in all, a rather nice day!