Feb 2005 Cold Snap

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It was like a system straight out of winter. An upper trough and a low developing over Victoria dragged cold air up from way down south, making the 3pm temp recording on the 1st the coldest Febuary recording for this time in Adelaide for 50 years! A rain band with the trough arrived around 3:30pm on the 1st swinging the wind around to the SW and bringing 6mm of rain to my location with it. By itself this would have been a nice system for Febuary, our hottest and driest month. However this was just the begining. Following the pasage of the rain band the wind swung further to the south dragging cold air and heavy showers with it. The radar was amazing for this time of year, dotted with what appeared to be winter style coldies! .

Temperatures were simply astounding for feb. That night we dropped to 7.8 degrees and had a night of heavy sporadic showers that saw a further 6mm fall overnight giving a mornings total of 12mm on the 2nd. This was one of the highest totals for the ranges with only heavier falls from east of the ranges where the heavy showers were concentrated. This in itself was unusal as Adelaide and the more northern ranges were behind a significant rain shadow for most of the system which delivered little rain to them.

The cold and showery conditions continued into the day with more heavy and sporadic showers all day. Small hail accompanied many of these showers which were wide ranging in their falls, from Murray Bridge to the N/Eastern suburbs. Some showers coating the ground in a layer of white! Remember this is febuary! Worth a mention is that this low over Victoria produced continuous rain for over 24 hours giving Melbourne it highest EVER 24 hour rain recording of 120mm and a host of flood warnings for nearly every river in the district!!!   The synpotic to the right shows the developing low over Victoria interacting with the high in the bight to drag up the cold air and showers/hail over southern SA..

Wednesday the second was also one cold day indeed. We had a maximum of only 14 degrees which peaked here for a few minutes when the sun broke through the cloud layer for a short time. Most of the day was a mere 11-12 degrees! The astounding minimum temp of 6.1 dgrees which was the coldest of the system fell on the morning of the 2nd.

The rain and hail during the day bought a further 12mm to the gauge by 6:00pm. 24mm in total from the system up to this time.

	The graph to the left (recorded from my automatic weather station) clearly displays the frequency and intensity of the passing showers. Yet again the rain did not penetrate significantly to the Adelaide Metropolitan areas who recorded very little rain that day. There were isolated showers on the plains and one significant hail shower managed to dump on a small area in the N/E suburbs by Gorge Rd.
	The temperature graph to the left is more indicative of winter. The smoothing effect of the stevenson screen on the air temp sensor is clear. The white line indicates the sensor in the screen while the green line is a sensor not shielded from solar radiation. The importance of a screen is paramount for good temp readings. As can be seen it was one cold day alright! To add to the cold stories 40cm of snow fell in the Australian Alps. Skiing in feburay!
	The satellite image from during the day on the second is stunning. A patchwork of cloud and cold air!

 

The rain and hail continued overnight and into the the morning of the 3rd giving yet another 12mm and a total of 24mm for the past 24 hours and an accumulated total of 36mm. By now the ground is sodden. Other falls east of the ranges were quite high as well. Mannum for example received 19mm for the same period. This is traditionally a dry spot, even in these types of conditions. Again Adelaide missed out. Interestingly the gale force winds which were being felt on the coasts never penetrated inland to us with conditions quite calm in the SE ranges.

The conditions continued into the 3rd with the low intensifying and moving slowly westwards to be centred right over Melbourne which continued to be hammered by wind and rains.

The third was actually our coldest day, with a maximum temp of only 12.1 degrees. However the temp hovered around the 10 degree mark for most of the day. By this time the intensity and frequency of the showers had decreased somewhat. The following morning, 9:00am on the 4th a further 6mm was in the gauge giving a total for the system in excess of 40mm. This was far more than I ever expected and was one of the highest totals for the state for this period. Rain, hail and freezing cold temps, a real blast of winter in the middle of summer! AMAZING!

CLICK HERE FOR IMAGES FROM THE EVENT