Notable Weather Events Page 33

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7-11th August 2007 Gale fore winds.

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The synoptic situation as seen to the right remained constant for nealry a week and saw 5 days of constant non stop gale force winds buffet the hills, mid north and Mallee. At my location the winds were relentless. The 7th saw a top of 70.9km/h, 8th 52.1km/h, 9th 64.6km/h, 10th 82km/h and the 11th 53.6km/h. But these were not just isolated gusts! A 34 hour snapshot of winds from the 9th to 10th can be seen in the graph below. It clearly shows the relentless nature of the winds. Making it worse was warm temperatures and dry conditions maing this one shocking drying week indeed. Right - Synoptic chart from the 10th Below - Graph snapshot of the winds

August 2007- Groundhog Year?.

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Warm temperatures approaching 20 degrees, weeks without significant rain, nothing on the medium term forecast or the long term forecast. Is 2007 following along the same disturbing lines of 2006? As we approached the end of winter many districts are become increasingly worried about the prospects of the season. The BOM 3 month rainfall outlook echoes the worry reporting a 60% chance of below average falls from August to October. (see map below right)

Temperatures began rising unseasonally early compounding the low rainfall problems while huge powerful highs ridging back over South Australia pushed any frontal systems far south of the state. The 10 day rainfall forecast issued on the 25th August is worrying indeed. (see below left) It will signal an end to many districts cropping potentials already on the edge.

Coulta Farmer and contributor to this website, Brian Foster, is involved in drought response in the Eyre region. He reports that as of late August the process has been reactivated with increasing numbers of farms with NO CROP THIS YEAR as far south as Tumby Bay(!!) and also extensively across the top of the west coast region and west to the Ceduna. These areas will not recover it is reported!! A similar situation exists in areas of the Riverland. A disturbing result of yet another bad drought year.

Looks like China will be feeding South Australia again............

30th August 2007- Total Fire Ban in Winter?.

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A week previous to the 30th was an aweful day of heat and gale force winds, causing irreparable damage to many cropping districts across the state. Could it get any worse we wondered? And then came this forecast for the 30th August. It's still officially winter remember! Forecast for Thursday Dry and warm to hot at first with northerly winds increasing to strong and gusty during the morning. Local dust haze in the afternoon. Extreme Fire Danger in the Mount Lofty Ranges. City: Min 11 Max 28 The Kent Town record for the 30th is 27.8 degrees in 1982. Will it break this? Could it break the all time Adelaide august record of 29.1 set in 1911? Right - Forecast synpotic of the 30th

There could not be a much worse scenario. The day will cost the state millions and affect communities for years to come. Then there was this issued.....

Media Release
4:30 PM 29 August 2007

Media and the public are advised that TOTAL FIRE BANS have been declared for Thursday 30 August 2007 in the following Fire Ban Districts:
West Coast
Eastern Eyre Peninsula
Lower Eyre Peninsula
Mount Lofty Ranges
Where Total Fire Bans have been declared, extremely hazardous fire weather conditions are predicted.
The Total Fire Ban will apply for 24 hours from midnight on the day of declaration to midnight on the following day. Agencies are advised to activate their Total Fire Ban procedures in preparation for these predicted fire weather conditions. Residents are asked to implement their Bushfire Action Plans. Landowners are asked to adhere to their local harvest codes of practice. These codes are available from your local council. Landowners are also asked to ensure that any burn off activities conducted today are fully extinguished before midnight tonight.

For further information contact the CFS Bushfire Hotline on 1300 362 361.
Authorised by Total Fire Bans Officer, SA Country Fire Service

A total fire ban in Winter! 2006 is starting to look like it was a good year in comparison!

UPDATE!!!!

The 30th exceeded all expectation of temperature extremes, breaking, no smashing records across the state. For a start I recorded my hottest ever August day which peaked at 24.2 degrees at 13-52. The previous record of 20.9 on the 25/08/04 was wiped off the board by an amazing 3.3 degrees!
Adelaide Airport's top of just 30 smashed the previous record set on the 25/8/1977 by 2.7C. The Kent Town top of 30.4 also smashed the previous of 27.8 (29/8/1982) also breaking the old West Terrace record of 29.1 (31/08/1911) making it the hottest Adelaide august day since records began in 1887!!!
heir highest
Many other stations recorded their hottest ever maximum temperatures for August, including Ceduna at an incredible 33.6 and Port Augusta at 32.3 degrees. The full list of records can be seen on Laurier Williams excellent site HERE.

Winds were also extreme with severe winds recorded from Ceduna, Eyre and Yorke Peninsulas and the Adelaide and Hills area. Raised dust reduced visibility across the agricultural areas. Gusts to over 90km/h were recorded locally at Sellicks hill. I recorded a maximum gust of 77.1km/h at 16-08. Sustained winds buffeted my hilltiop for 10 hours before the wind change arrived and conditions abated. The WX graph of the day is a shocker (see below).

The damage caused by such conditions is likely to push many producers to the wall. The impact is so profound that it even made the mainstream city press, that normally miss such events in their elevated platforms of disconnection from the real world. This is perhaps a little harsh, but the fact remains that it is all too often true. The prospect of any significant rain is very low for all areas which will compound the damage caused by the days extremes. Right - Graph of the wind from my WX in the Bull Creek ranges
One thing worth noting is the sudden and abrupt wind change that is so visible on the graph above as a drop off in the winds at the end of the period. This was noted with spectacular results by the new Bucklands Park doppler radar wind output. You can see where the very strong northerly winds almost instantly switch to the west along the squall line of the wind change. Its an amazing image and one worth posting here as about the only good news story of the whole day! Right - Doppler wind output from Bucklands ppark showing the sudden wind change.

5th - 11th September 2007 A front, A low, A Failure

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The models seemed to be confident about this one. It certainly looked pretty good by the Satellite and Synoptic.

Right - satellite and synoptic. Looks great on paper!

The BOM were pleased with its potential and issued this in their "notes" on the 8th

IDS10030
AUSTRALIAN GOVERNMENT - BUREAU OF METEOROLOGY
SOUTH AUSTRALIA REGIONAL OFFICE

NOTES ON THE WEATHER
Issued at 5:25 am on Saturday, 8 September 2007

FORECAST EXPLANATION:
A low is deepening southwest of the Bight and will drift slowly eastwards during
the weekend and pass just south of Mount Gambier during Monday. An associated
cold front near the western border of the State is forecast to reach Nullarbor
around 9 am, Ceduna mid afternoon and Cleve around midnight. Isolated thundery
showers are expected to occur near the front over the Western Agricultural
district today, before reaching pastoral areas southwest of Woomera, together
with Kangaroo Island and Yorke Peninsula this evening. Warmer northeast to
northwest winds will strengthen in the west and in southern coastal districts
ahead of the front, with winds turning milder west to southwest and temporarily
moderating in its wake. The Fire Danger is expected to be Extreme in bushland in
the Western Agricultural district today. Fine weather with increasing cloud is
forecast in remaining districts ahead of the front.

During Sunday the low will move to south of Kangaroo Island by the evening.
Isolated showers and thunderstorms associated with the front are expected over
eastern districts. Isolated showers associated with the low will persist over
agricultural areas to the west of the front, increasing to scattered showers
with isolated thunderstorms over southern agricultural areas. Strong winds are
also expected with this front and low.

The low will move from just southwest of Mt Gambier on Monday morning to south
of Melbourne in the evening. Scattered showers are expected over agricultural
areas and southern pastoral districts, decreasing to isolated light showers
north of a line Ceduna to Hawker to Renmark. Showers will be more widespread
over the Mt Lofty Ranges and the Lower South East District. Isolated
thunderstorms are also forecast over Kangaroo Island and the Lower South East
District.

A high is expected to be centred near the Head of Bight on Tuesday morning,
moving east to be centred near Woomera in the evening. This high will cause the
showers to become isolated and contract to the southeast.

Cumulative rainfall totals until midnight Tuesday are expected to be 5 to 10 mm
across the southern agricultural areas, increasing to 10 to 20 mm over the Lower
South East District and Mt Lofty ranges, with local falls of 20 to 40 mm
possible in the Mt Lofty ranges. Fall of 2 to 5 mm are expected over the
northern agricultural areas and southern pastoral districts, decreasing to less
then 2 mm north of a line Ceduna to Hawker to Renmark.

The outlook for Wednesday, Thursday and Friday is for fine weather at first with
freshening north to northwest winds. A front will move across South Australia on
Thursday with some shower activity over agricultural areas and southern Pastoral
Districts and strong winds. Showers and winds will ease during Friday as a high
forms over the Bight.

HHMMMM - 20-40mm over the Mt Lofties. Well that would be nice! However traditionally, these setups leave my area in no-mans land rain wise. With South West streams in action on expected low wraparounds the rainfalls usually concentrate over the central and northern hills, sometimes spectacularly! A small window can exist in the westerly flow for my area - sometimes.

And this is pretty much exactly what happened. There really is not much to say. There were a few thunderies around pre low arrival. Small convective storms in the mallee and mid north gave some localised drops. The odd rumble of thunder and lightning flash was to be seen. Come evening these collapsed with the suns heating no longer driving development. Rainfalls from these cells were patchy at best and not widespread enough to be seen as significant. Its worth mentioning at this point that some of these cells went pretty much wherever they wanted to, almost wandering aimlessly across the landscape! One such cell moved south down Yorke Peninsula taking a right hand turn and heading off towards Adelaide across the gulf. Meanwhile a bit further north similar cells were moving in an easterly direction! Amazing to watch.

The low arrived with a nice NW airstream that was strongest just east of the ranges. Lines of cells built up during the day (9th) with some nice heavy cores. However they were too fast moving and too localised to be significant. By evening they were all gone.

As the low progressed the westerly flow proved to be quite productive moisture wise - only it never really came south of the freeway line through the hills! The main moisture stream which was evident on the satpic stayed just north of my location. My only real chance for good rain evaporating with it (terrible pun!). By the morning of the 10th I had received a massive(not!) 3mm from pointless drizzle. But the central hills, firmly embedded in the cloud moisture line had nice falls between 10 to 13mm with Lenswood to western branch getting the highest.

Then came the South Westerlies as the low moved slowly eastwards. We all know what I think of SW moisture streams. Bah Humbug! Impressive red cored cells were to be seen strengthening over the gulf as the back edge of the low "wrapped around" from the south. They were unfortunately fast moving and while torrential to those caught underneath, did not deliver significant rain totals. But they moved in this line all day and by the morning of the 11th falls over 10mm had accumulated over the northern ranges with 15mm at Mt Crawford.

Meanwhile down south we were swamped with drizzle. Just 6mm in the gauge to the 11th from 24 hours of light inconsistent showers. As expected rainfall distribution of significance stayed "north of the freeway". In fairness my 9mm total from the event was desperately needed, but the torrential consistent falls over the northern ranges would have been a godsend! Any wonder my dam has not filled for many years.

Falls in excess of 20mm from the 2 days were recorded from some spots. (Lenswood for example), but nothing approaching the "possible 40mm" on the original forecast. It was nice to see some rain, but a bit of a flop as the system downgraded and weakened with each passing hour.

It should be noticed that yet again the Riverland and some mallee disticts again missed out sounding death knells for some crops. I better say it again - "What a shocker of a year!"

 

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