Torrential
Rain & Severe Winds Lash
In the morning the first thing I wanted to do was check the obs. The SE change was looking to slow down, but I wanted to make sure it had. At midnight, the SE change was through Double Island Point…the 6am observations showed about 70km north, Hervey Bay was showing a N’ly – perfect! In 6hrs the SE’ly had practically gone from racing up the coast at 60-70km/h to stalling totally. A check of the satpic showed that the cloud to the west had thickened up a little…but not too much. That was until the latest image came in – in just a couple of hours the cloud band had thickened enormously!!! This virtually almost ruled out the western option as we didn’t want to get caught in the cloud. A check of some forecast charts showed a nice region of LIs, -2 over Brisbane increasing to -4 around the Gympie region, -6 to -8 over the remainder of Wide Bay and -8 to -10 in northern Wide Bay and southern Capricornia. A widespread region of -4 to -6 LIs were also present in the Downs, however they were going to be under the influence of the SE’ly and mainly were deriving their instability from the upper trough. I wanted to be in the N’lies, not to mention better shear. The Downs low level shear was quite poor, barely getting much above 20-30 knots until well up into the jetstream, and 850mb barely registered, although I was thinking it was being underestimated a bit. The shear in the Wide Bay/Capricornia area looked much better, although it wasn’t really ideal still. However shear ended up being quite strong from what we noticed in the Wide Bay area! We also thought storms would develop area around the Downs/SE Coast district, and wanted storms to develop later with a higher cap. A nice ridge of high teen 850 temps were pushing over Wide Bay. Wide Bay it was… Jason left his place just before 7am and arrived at my place a bit before 8. We packed his stuff into my car and then headed north. It was basically overcast and drizzle for a large part of the way to the Sunshine Coast.
It got a little warmer at Gympie, but was still cloudy as it pushed 24C at 10am. Filling up fuel at Gympie it felt different, the SE’ly wasn’t nearly as cool. As we went further north the sky eventually started clearing with extensive blue patches of sky appearing west of Maryborough. The temperature started increasing, and the wind had changed directions – gusty NE’lies! Just after midday we arrived at Gin Gin, it was ~31C with a DP of around 22-23. It felt quite sultry, even though it was partly cloudy. There was a lot of junky Cu.
We discussed where we wanted to be, we didn’t want to go too much further north than Gin Gin. So we decided to grab some lunch (the Traveller’s Café is a nice old fashioned place, a little more expensive but some good food there! Had some nice home made pies)…of course, you could also visit the local Gin Gin Pie station too if the café was closed!
After talking to the owners of the café, they suggested two lookouts, one was the dam about 20km north of the town, and the second was Mt Perry. We had a look at Mt Perry on the map, we weren’t too sure if we wanted to be there as trying to get out of Mt Perry looked like potentially being a hassle. More so if we wanted to go south, and given there was a good NW’ly flow in the shear, it was likely things would move SE so that wasn’t going to be an ideal option. We decided to head north to the dam and wait there after lunch. It was a reasonable view from the dam…the view further north was better than the areas further south, but it still wasn’t bad! The dam very empty though…testimony to how dry it has been lately. We sat and waited for a bit…there appeared to be something developing to our south and southwest but it was difficult to make out. Just then an SMS made me jump…a severe thunderstorm warning had been issued for the Wide Bay area! It was kinda funny though – because we both looked up and said “ok then…where are the storms.” The sky cooperated for once and the lower Cu began to clear to our south and southwest and revealed a nice wall of updrafts that had recently glaciated.
Minutes later they produced some nice pilieus and were skyrocketing upwards!!!
The N’lies had increased recently also, constant 20 knots or so which was quite impressive I thought. We decided to head south a little to get a better view of the storms, we didn’t want to head too far south as we thought that we’d need to head north again as the storms to the south built back on a line towards the NW. As we headed south we got a call from Jonty at the BoM, he mentioned that the particular main cell we could see was showing some high reflectivities quite high up – 50dbz at 11km!!! We also tuned into the static…previously we had tuned into my favourite static listening, 531. But we were picking up too much distant static from the storms developing over SE Coast and the Downs so we tuned into a higher channel, of which there was virtually no static. This changed – static had gone from hardly anything close by to constant in the matter of 30 minutes!!! Passing south of Gin Gin revealed a fairly awesome sight. A very large storm was now to our WSW, but it didn’t have many features from the distance we saw at it. The inflow around the storm was quite considerable! Gale force NE’lies were flowing into the storm and raising large areas of dust – that and breaking small twigs and leaves off the trees around us!
We headed towards Biggenden, but stopped about 25km north of there. A gustfront was developing and we wanted to take some footage of it – it was rapidly approaching.
Even though the guster was disorganised, the fact that it was approaching so rapidly was already a warning that the cell would probably have some strong winds in it!
On the northern edge there looked to be a wall cloud, it was tucked in on the edge of the gustfront and on the northern edge, but it looked to be rather outflowish and it did certainly become an outflow feature later on.
We headed south, and we wanted to head west to get ahead of the storm. But that wasn’t going to be the case with the storm overtaking us to the NE of Biggenden. It was 3pm and almost pitch black, I had to turn my high beams on!!! (The Isis Hwy capture shows how dark it was, as if it was dusk) It wasn’t a classic type of storm setup where the wind sprung up very quickly with the rain. Light rain and strong winds (60-70km/h) came first, before some heavy rain with winds of 70-80km/h...
and then torrential rain with constant winds of 80-100km/h!!! It was horrible visibility, sheets of torrential rain were blowing over the car – branches were coming off the trees, one of which hit the car roof and gave an almighty thump!
It sounded how I would imagine a cricket ball hailstone to sound like. There was plenty of water beside the road, in the end we pulled over and waited. The storm was going to be moving too fast to the ESE for us to catch it so we decided our best bet would be to head north again and wait for more cells to develop along the line. Driving back we saw one tree that had basically been snapped in half beside the road, along with lots of branches scattered along the roads (had to do some evasive driving to avoid running over them!)
Heading north you could make out the edge of the outflow region, it was just massive! It was like being in a giant cave…quite eerie to an extent.
|
