A trough was advancing eastwards on this day and was going to be pretty much positioned over SE QLD.  An intense cold pool was moving into northern NSW with 500mb temperatures dropping to -21!!!  Our 500mb temperatures were a fair bit warmer at -11C, but the result was a strengthening in the shear profile.  Mostly NW winds except for the surface, but 20 knots NW @ 850, 25 knots NW @ 700, 50 knots NW @ 500 and 80 knots NW @ 300.  Given the strong linear forcing on this day, a squall line was most likely…but I wasn’t going to rule out the chance of supercells (although really that can never be ruled out!)

I had to work again in the afternoon – so I was a little concerned that 850 temperatures were cooling.  The day before had 850 temperatures of around 18C, which meant storms didn’t really take off until after 4pm (around when I finish).  But on today 850 temperatures were around 16-17C, still quite good but it would mean that storms would develop earlier as we’d have the additional affect of the trough forcing.  I didn’t want early storms as I’d be in the middle of work when they developed!  Which is pretty much what happened!

I work from home, so in the afternoon I was watching the sky and radar.  A line of storms had developed in the Downs and were advancing east.  One storm in particular looked quite nasty and severe – but it joined into the squall line and moved across the SE Coast.  While doing forecasts, I ducked out to the top of my street and was able to take some quick snaps of the gustfront as it was approaching.