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31st August 2008 Our Heaviest rain of the year??

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A NW infeed, a trough and a front. But its not the mechanics of this we are really interested in but rather a small event that occurred within. At 4am of the morning of the 31st August 2008 a small line of heavy rain moved over my location. See image to the right with a graph from my weather station recording the rain spike and a 200% enlarged radar grab from Bucklands park. It was almost torrential and mixed with small hail and also unfortunately rather short lived. But why is this of note? 2008 has been a rather noteworthy year due to the lack of noteworthy rain in my area. Its been hot, cold but substantial rainfall intensity has been mostly nonexistent. This little spike of heavy rain and hail is (thus far) the heaviest rainfall I have recorded for 2008!

The really sad thing to note here is that in the scheme of 2008 events such a tiny blip of heavy rain is insignificant when looking even just a tiny bit further abroad. Such heavy rainfalls are seen regularly in most locations. From the same system even many even more inense cells were to be seen regularly over the northern ranges. This was the only decent intensity rain to move over my area. I have put together a small grab of historical (from 2008) radar images that graphically display high intensity rainfall cells over much larger areas. These can be seen in the image to the right. Don't forget my grab above is at 200% magnification while the ones to the right are at normal resolution! Such falls can be found with regularity from all types of systems. The complete lack of decent intensity rainfalls and significant 24 hour falls from this winter in my area can be graphically displayed in small dam catchments. In fact such a size of intense falls as displayed in the radar grabs to the right I have NEVER observed over my location in 6 years of close radar image scrutiny.

7th September 2008 Southern Adelaide Storms

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When you read this report make sure you take note of what is written above. This reinforces what is written above.

You know spring has arrived when the interesting and significant rainfalls occur somewhere other than my location. And on this day the arrival of spring was well and truly cemented! It began overnight with a small rainband that stopped short of delivering a drop south of the freeway and up to 6mm from Gawler to Mt Crawford. Very much spring/summery in rainfall distributions and system progression. As this band passed an interesting SSE surface flow collided with the NW band and pushed up some rather interesting and locally intense convective thunderstorms. First of the season! They were first observed running up lower Yorkes Peninsula (Minlaton copped 11mm in a rush) and soon developed into another line just east of the ranges. I sat outside watching the surface moisture move overhead of my location and explode upwards AFTER it had passed developing into an intense line of rainfall deluge. This passed through Hahndorf and surrounds before dropping off before the western range edge.

A tiny bit further west more crisp bubbling updraughts formed as they yet again passed overhead and joined with the initial storm remnants and formed what was arguably the most impressive rain of the day with 18mm at Happy valley falling in less than 30 minutes. Its interesting and depressing in some ways to note that in all the years of living at my locaton I have NEVER recorded such rain rates as fell from these small storms. I could do certainly with a serious downpour this year, especially with a dam only 1/3 full and the highest 24 hour fall for the year to date yet to reach 18mm. The progression of the system and just how close it came to my location is best left to the radar loop. Its fascinationg to watch the colliding air masses!

A few pics of the storm cells from my southern perspective can be seen here - PIC #1 - PIC #2 - PIC #3

12-15 Sept 2008 return to winter

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Cold, hail, rain and WIND WIND WIND. Read the report HERE.

27th September 2008 - record heat

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A lingering weak trough and continued northerlies for the second day running results in significantly and unseasonally high temperatures across the state. From almost 40 degrees in the far north to 33.7 in Adelaide. Not a record for Adelaide, it was however somewhat different for my location.

It rose to 27.1 at my location. This is the HIGHEST september temperature I have yet recorded. Not just by a small amount either, the previous september record was 24.9 in 2004. A 2 degree smashing of my old record!! Interestingly there was a daily midnight to midnight temperature variation of 18.8 degrees with the overnight low dropping back to 8.3 degrees. Also of interest was an early morning temperature plummet (on the 27th) associated with a short burst of cold southerly air from a thick fog that was blanketting areas east of the ranges. This had a dramatic effect on temperatures which is graphically represented by the image to the right. However the biggest problem with the day was the wind. Gusting to above 60km/h in my location (and many others) such gale force winds combined with such high temperatures was hugely damaging with unseasonally high evaporation rates causing huge soil moisture losses across the state.

Even worse was an almost zero prospect of reasonable rain to follow the winds and heat leaving crops statewide blasted and yield potential lowered and likely in some more marginal locations written off. September 2008 had already delivered well below average and insubstantial rainfalls and then to add such a day as this will leave the 27th as high in the top ten of worse and most damaging days of 2008.

A day to forget..........

Spring 2008 failure and more...

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My average rainfall for september and october is 173mm. Winter is ending, temps are warming and the atmosphere is generally a little unstable and still winter wet. But in 2008 we skipped spring and went straight to summer! The rains simply switched off. As of October the 27th these were the statistics for the September and October rainfalls from Meadows township ....

September Rainfalls - Min :22.3. Max :223.8 mm Av : 98.3mm
October Rainfalls - Min : 6mm Max : 178.8mm Av : 74.8mm
Combination of September and October - Min: 47.1 Max: 324.7 Average: 173mm.
The lowest combination fall of 47.1 was in 1914. This was truly an extraordinary season being almost half of the next lowest total which was 73mm in 2004. A genuine aberration.

So now lets look at 2008 combinations. September saw just 42.8mm. This is the 8th lowest september on record. October until the 27th was on just 4.5mm and well on the way for making the lowest October on record. Then an unexpected moist WSW airstream following a front delivered a hugely surprising 8mm on the 27th itself more than doubling the months meager totals to 13.2mm.

As it stands to the 27th Spring rainfalls are at just 56mm. This makes it to this point the second lowest September/October rainfall totals on record!

Now for the graph of the Meadows town Oct/Sept rainfalls from 1887 - 2005

Not a very good situation at all. Worse is that the dry has been accompanied by warm daytime temperatures and strong winds exaccerbating moisture loss through evaporation. A troublesome and difficult year again.

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