Michael Thompson's Australian Storm Chase DiarySevere isolated storm -Southern Highlands, NSW, 9th March 2000 A small downburst followed by hail was the highlight of the storm, note in the first picture how the cold outflow is being drawn up into the fresh base on the right. There are some setups that almost guarantee storms, even in a season as poor as the 1999-2000 one. Overnight we had steady rain and wind from a small low pressure system, but this cleared rapidly around 9am as the low moved southwards. As long as the winds do not go offshore or the trough pass to the NE this can be a classic setup. Things weren't to bad in the upper atmosphere as well with a jet stream exit region to the NE, if fact a separate cloud mass could be seen to the north and it was slowly making it's way south, but that was a few hours yet. I was fortunate enough to be off work, so about 2pm with some congestus over the ranges I set off to Picton. To be honest at this stage I was a little worried as nothing had happened, I took my wife and baby along, if nothing else we could have a drive in the countryside.
Over
the next half hour the storms to the south merged into a line, from
a distance one could be mistaken for thinking of it as a single unit,
but as I got closer you could see that where several cells. Fresh updrafts
kept building on the rear NW flank, a strong jet was taking the storms
SE rather quickly. This cell was the last for the day, the line had lasted about 2 hours, but suddenly fell apart. The radar loop shows this all too well. Click to animate, thanks to Matt Smith for saving this loop. Image courtesy of Bureau of Meteorology
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