As a weak trough edged slowly across western Victoria early on the 2nd March, this system triggered slow moving middle level storms. It wasn't until 3.30am that I finally forced myself to bed and slept restlessly until 6am.
The Victorian summer of 1998/1999 was to say the least, thunderstorm active even at my home in Leopold, 10 km east of Geelong. I had already recorded more than a dozen good storm days since Christmas Eve - normally I would see half that amount in a good summer period. The storm activity though had not been the usual cool change type, but were mostly convective pulse storms, some of which became severe. Another unusual factor was the almost total lack of speed shear associated with most of the activity and there were very few night time storms which reflects the daytime convective nature of outbreaks......
At 6am the whole of the western sky was filled with altocumulus castellanus and decaying anvils (well known Sydney storm chaser Jimmy Deguara would have had heart failure about now!). The middle layers were simply explosive!
By 9am middle level Cbs were already popping up over the west central district of Victoria, and a line of enhanced castellanus was pushing very slowly eastward just to the west of Geelong.
Castellanus at 9am - Geelong area
Photo - C Herbert (ASWA archive)
Some odd things started to happen by 10am: the temperature had reached 26C and humidity was showing 75%. I have to say this is most unusual for my location. As the temperature increased so did the humidity so by 10.30am humidity was 77% and the temperature 28C and I calculated dew points around 22C! I rang Jane ONeill (Victorian ASWA representative) and got into very excited discussion about the way the day was shaping up. There was indeed a weak trough just west of Geelong moving only slowly to the east. Dew points were generally above 20c over most of central and western Victoria and there was a huge area of moisture over most of south-eastern Australia. . By 11am a band of congesting cumulus had formed along the same line as the castellanus - in places cumulus was pushing through and simply combining with the alto cloud . I couldn't stand watching any more and grabbed my SLRs and dived into my trusty Subaru and headed west. By 11.15 the entire western half of the sky was filled with dark blue lines of deep cumulus almost hiding all of the alto cloud. Already in places some of the congesting cumulus were glaciating and dropping small heavy rainshafts and still the whole of the western sky grew darker. It's very hard to explain, but the rapidity of the developing storms was breathtaking!!! The CAPE levels were enormous.
I drove north from Geelong along the Princes Hwy and fuelled up at Corio and bought my mandatory chocolate bar and coffee. By midday the area of scattered heavy showers to the west of Geelong had already merged into a very large multicell with a huge flanking line and strong lowerings. A closer look at the northern end of the wall cloud showed some rather weird scud........ this scud area was moving north along the flanking line and I almost forgot my car at the petrol bowser - and still with coffee in hand, saw this scud start rotating and I ran to a better vantage point, but realising there was now a queue for petrol, I headed back to the car and raced off westward along the back streets of the northern suburbs of Geelong and finally arrived at Corio airfield in open country about 10kms northwest of Geelong.
(check the last image in the loop -
02:00UTC)
Radar loop courtesy of the Bureau of Meteorology.
MSL Analysis 03Z - 1pm EDST
Courtesy of the Bureau of Meteorology
I checked my watch (12.25pm) - the atmosphere that greeted me was nothing less than awesome!!!! The massive flanking line was building northward very rapidly ..... a mammoth rain area had developed just to my southwest ..... thunder rolled almost continuously ..... Cgs flashed everywhere .....a wall cloud lowering barely 1 kilometre to the west was lowering and building back towards the north. It became remarkably dark even with the very bright eastern horizon. I snapped my Canon AE1, rolling off almost 10 frames before I realised what I was looking at. The wall cloud lowering had started to curve inwards towards a very large black rainfree Cb base!!!!
A careful look at the higher Cb base showed ROTATION!!!! -IN FACT THE ENTIRE CB WAS ROTATING!!!!!!! The wall cloud started to wind up and spiral into the centre. I was standing barely 1km from a MESO! I had just snapped another frame when a large thump took my attention - a huge hailstone bounced on the gravel road just in front of me (at least 4cm). The wall cloud spiral tightened up ....... A CG FLASHED ONLY METRES AWAY ......VORTICES STARTED TO SPIN UP IN THE FIELD ONLY 100 METRES FROM ME .......... The dust vortices spun and moved at an angle towards the meso centre ......more large hail fell ........the wall cloud looked magnificent as it spiralled and rotated 360 degrees. Some of the dust vortices were very large and I could hear them even under the echoing thunder.
I HAD WAITED 40 YEARS TO SEE
SOMETHING LIKE THIS!!!!!!!!!!! 
Rotating meso - Corio airfield
12.37pm
Melways - Map 223, E2
Photo - C Herbert (ASWA archive)
The power of this storm was phenomenal with more large hail falling. I headed for my car and took one last photo, and sped away - this area had become too risky. As I headed east large vortices continued to spin up to my north. Only 100-200 metres away a large spin up crossed the road just ahead of me. The convergence around this meso was remarkable. I raced east about 3kilometres and pulled over to watch this massive pulse mature into an intense deluge. This storm moved over the northern suburbs of Geelong dropping better than 50mm of rain in 30 minutes 100km/hr winds and 4cm hail and caused flash floods and general mayhem.
Over the next two hours, the focus of the updraft point continued to build back along the flanking line, occasionally showing rotation. The meso area moved from the northern suburbs of Geelong to be located over Bacchus Marsh about 2.30pm. From this time, the storm system had taken on the characteristics of a squall line as the complex became outflow dominated. Melbourne Storm Chasers, Andrew McDonald & Chris Gribben caught up with the storm west of Melbourne and encountered hail and torrential rain. (see report: Western Suburbs, Melbourne )
FOOTNOTE: I submitted my photo of the meso the next day to the local newspaper and had it rejected because there were no people standing in the foreground!!!!!!!!
ACKNOWLEDGMENT: to Jane ONeill, who was tied to her desk at work, but managed to provide a steady stream of radar information to ASWA members out in the field throughout the day.
CLYVE HERBERT - LEOPOLD, VICTORIA, AUSTRALIA - MARCH 1999 Phone: 0414 771 108
Updated 19th April 1999 - J ONeill