Hi all, when I left work at 5.15pm today I sure didnt think i'd be reporting on a chase tonight
but you just never know and I was treated to some rapid development.
I was on the western ring rd heading nth at around 5.30 and saw a very ordinary updraft trying to punch upward at what appeared from my vantage to be the southermost end of a relatively short SW/NE line that had developed moving NNE (at a guess), and on a convergence line of sorts as it appeared. As I drove I got closer and lost sight of the smallish Cu tower above me but was amazed at the rapid development of large amounts of very very low scud underneath and out towards Tullamarine/Sunbury. This was followed by rapid development of a significant rain free base on the southern/eastern side and heavy precip area on the northern side. I went east on the ring road, north to Epping and then west towards Sunbury where I had a good view of the storm.
The updraft base of the cell appeared to just about stall in this area near Sunbury for up to 30 minutes as I drove westward. It took on some impressive low level features including consolidation of the southeast part of the base into what was appearing like a precurser to a wallcloud for a moment, and two distinct inflow regions - one from the east which was dark and dense with moisture and another from the SSW which was slightly higher and less organised, but deeper.
I was on the phone talking to John Allen at this stage and I could see the northern precip area absolutely bucketing down to my NW and said I thought there would be hail - I was right! John texted me soon after (he now had radar access) to say he thought he could see evidence of a short lived vault-like feature and even a hook echo. I will leave it to him to add to these observations.
Not long after, the RFB had unfortunately turned to precip and it was obvious to me that the cell was no longer stationary but had resumed a north-easterly track. I turned north onto Oaklands Rd and drove into the core as it moved across my path, where I encountered torrential rain for several minutes, flash flooding (yes the road was covered) and pea size hail. Turning eastward onto Craigieburn Rd (I think) I managed to get onto the southern edge of the core where I got more pea size hail and more heavy rain for a few minutes before it cleared away to my north-east.
I then contently drove eastward toward home watching as the cell moved away to the NE.
Talking to John again via phone and text, he informed me that radar showed another cell had caught up to and interacted with the main cell from the SW (where I couldnt see) and this coincided with my description to him of the main cell 'dropping its guts' (when I was approaching the core). Whatever the mechanics were that appeared to be building a nasty storm were clearly affected by the second cell and outflow rain and hail was the result.
I havent seen such rapid development from an otherwise innocuous TCu in Melbourne before so i'm glad I was observant on the way home!
From what I can tell, the BOM did not issue a STW on this cell and im not really surprised because it all happened so quick. Im sure John will have some observations and possible explanations for this short and sharp event.
BTW I didnt have my camera with me (spewing) so I had to settle for a few low res shots with my phone - doh!
Brad.
