Michael Thompson's Australian Storm Chase Diary

15th February 2003 - Briefly severe storm, Mittagong, NSW

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The storm reaches a severe phase

The outlook on the evening of the 14th Feb' was not overly promising for the 15th February. Moisture was abundant, perhaps too much so, but Lift Index and CAPE were quite low. Activity was forecasted to stay mostly further south and west.

On the morning of the 15th however a massive field of Castellanus told me that things were probably in better shape than the models indicated. The castellanus burnt off around 10.30am leaving a mostly clear sky. The coastal weather was sultry and oppressive. Around 1pm and the first congestus towers had gone up over the ranges.

I drove up the infamous Macquarie Pass onto the southern highlands. My initial interest was taken with a cell south of Moss Vale. It was the best cell in my visual field ( I rarely chase with radar or sat pic updates ). However I never really was happy with this cell. There was too much cloud crowding it for my like, the storm updraft was becoming shadowed by neighbouring weak cells. So I turned away and headed for sunshine. To the NW it was relatively sunny, so I edged towards the area, but not in a hurry as I did not want to lose touch with the only active cell in the area. My decision was rewarded when a healthy cell shot up to the north west, probably near Wombyean Caves.

The cell matured very quickly into a small but severe looking storm. Road setups prevented me from direct interception and the closest I could come was about 10kms. At this stage I was hit by gale force outflow winds. I knew this outflow could not go without stirring up something further back, so I turned around and headed back to Mittagong. It was here that a small line of activity exploded into a nasty looking storm, the photo at the top of the page does not do the storm justice, but believe me this cloud was very turbulent. It was around this time the a severe thunderstorm warning was issued for the storm.

Just east of Mittagong the rain became extreme. Visibility was down to just a few metres and winds were strong. No hail was experienced. The storm blew out over the Illawarra escarpment weakening rapidly.

An earlier storm near Joadja
An earlier storm near Joadja