A Somewhat Bizzare Looking Setup 12/7/2012

Have been keeping tabs on this system quietly for the past few days, wondering whether the models were taking a holiday or something was really going to pop up and yield some storms. Just to recap, its the middle of winter, most days have been 13 degrees centigrade and rather poor in Melbourne. So what the heck is going on in this chart below? Minus 5 Lifted Indices - in mid July?

Meet the implications of a reasonably strong trough and developing low which has managed to advect warm surface temperatures and moisture south into Southern NSW and Victoria. A quick look at an observed sounding yields quite a favourable profile for organized convection (and possible severe).

Of particular note are the surface temperatures (19C) and the dewpoints (~12C). So even though we are in a predominantly cool season - the relative warmth of the surface air has yielded an unstable environment. CAPE values max out at around 1000 J/kg based on surface parcel trajectories (mixed-layer shown), with substantial vertical wind shear in both the 0-1km and deep layers (~20 knots and 66 knots over the deep effective). This environment is reasonably favourable for rotating storms and supercells.

Now on to what is wrong with the environment. Storms fired overnight through South Australia, and while early morning convection did traverse the target area, I don't believe it will substantially alter the environment given it passed through early. The environment is also fairly heavily capped until the mid-afternoon, but it does appear that initiation will occur sometime during the diurnal peak. There are also the usual questions about effective moisture available to storms, as GFS tends to be a bit exciteable. On a gut feeling I would say chase today (but I have been known to go out and look purely because I am fascinated by odd setups regardless of implication). My target would be between Swan Hill, Victoria and Balranald, NSW. So will be watching closely to see how the forecast goes...

So this begs the question, why am I telling you about this? Because I can't chase it! Unfortunately the Hunters of Thunder are a man down today so will have to let this one go - its too far for a single man effort with limited light and this PhD needs finishing before chase season really gets rolling. Oh and for a little humor from my friend Skip Talbot: