Maleny Weather

If your rain water tanks are filled to overflowing it may be time to think of extra storage of this valuable asset. Here are some facts and figures:-

Rainfall amount is defined as “The depth it would cover on a flat surface assuming no losses due to evaporation, run-off or percolation into the ground”.

One square metre is 10,000 square centimetres. Therefore, 1 cm depth of rain covering one square metre would be equivalent to 10,000 cubic centimetres of water, or 10 litres. Or 1mm of rain would be equivalent to 1,000 cubic centimetres or 1 litre.

Each square metre of roof will give 1 litre of water for 1 mm of precipitation.

This method of measuring rainfall was introduced by George James Symons FRS. (1838 – 1900).

A British meteorologist who at the age of 22 founded what became known as the British Rainfall Organization, and over the next 40 years published detailed annual summaries of rainfall over the British Isles. By his untimely death in 1900 his voluntary observer network was some 3,500 strong. Today, this  system has spread to a vast world rainfall observation system with standards recommended by The World Meteorological Organisation.

The monsoonal trough is currently weak and lies to the north of Queensland and played no part in the week’s weather on the Ranges. There was a gradual build up of pressure along the east coast to form a ridge. This allowed a low level moist maritime air stream to come in over the coast bringing isolated showers, heavy at times, to the hinterland. On Thursday an upper level trough moved in to bring a continuous belt of rain measuring 15mm in the rain gauges. The week’s total precipitation amounted to 37mm, bringing the month’s total so far to 73.2mm. This is an abnormally low figure for the wettest month of the year.

The mean maximum temperature of the week was 26.5°C which is normal for the last month of summer.

The week started with TC “Jasmine in the north Coral Sea and as expected it continued to move away from the Queensland coast. Monday was a particularly hot day with a maximum temperature of 30.7°C and a stress factor of 40°C. It was also a trigger-day for people sensitive to weather change. The week’s major talking point has been the high humidity and the resultant mould that has been a problem in most households.

For the rest of the week and as far as the Ranges were concerned we had a weak stable pressure pattern with light winds and some isolated showers. The week culminated with an arcus roll cloud moving in over the ranges from the west early on Sunday evening. By 8.30pm a thunderstorm cell was overhead. The storm precipitated over 16mm, bringing the week’s rainfall to 44 mm.

The Ranges have experienced a week of isolated showers caused by a stabilizing SE moist maritime air flow over the coast. More often than not the showers arrived without warning and were of short duration but sometimes quite heavy while it lasted.  It has been a good week for umbrella sales.  On Saturday and Sunday the Intervals between showers were fewer and provided an opportunity for attending to the long grass on lawns that were unable to be mowed during the wet spell

Long range forecasters are saying our next rain spell is likely to originate in the monsoonal belt and then spread south reaching our area about 14 – 17 February.

WOW !   What a scorcher it was on Monday 9th. With a humidity of 46% and a steep fall in barometric pressure the afternoon’s temperature soared to a maximum of 35°C by 3.00pm. The Heat Stress factor recording was 46°C.  Not since 21^st January 2000 has there been such a high temperature in January. The cause of Monday’s abnormal temperature was a high in the northern Tasman Sea bringing a stream of hot air to the Ranges.

The dry spell that started at the end of last month continued on until the middle of January. The end came with a change in synoptic weather conditions as an east coast low of 1004hPa developed off the central Queensland coast. Over the next few days the low, together with an upper level system, brought substantial rainfall to the Maleny catchment plateau for the Mary, Stanley, Mooloolah and Maroochy Rivers. Flash flooding occurred in some areas

 Most of the heaviest rain precipitated from Nimbostratus cloud in the upper level system  whereas isolated showers were from surface maritime Stratocumulus clouds that came over the coast on an onshore air stream to the Ranges.

The heaviest 24- hour rainfall was on 25^th when 135mm was recorded. Last year, in a strong La Nina year, the 24-hour figure was 282mm. It was in 1974, at the time of Brisbane’s big flood Maleny recorded the highest ‘all time’ one-day record with 552mm.   Total rainfall for this month is 536.4mm, compared with January last year when 902.8mm was recorded.  The 119 year average for Maleny in January is 292mm.

Baroon Pocket dam is 103% full and is closed for water related recreation.

It was very muggy throughout the rain spell with the Relative Humidity percentage in the upper 90’s on many days.  [Mould is a problem in many households]. However, the mean RH in morning and mean in afternoon were 85% and 75% respectively.  Both within the norm figure, due to the dry first half of the month.

The mean maximum temperature for the month is 18.4°C, representing 1.3 degrees below the norm. However, the mean minimum is only slightly below average.

Not surprisingly, the Bright Sunshine hours recorded this month are exactly double the 76 hours recorded in January last year.

 The Bureau of Meteorology has released its Annual Climate Statement for 2011, highlighting a year likely to go down as the third wettest on record. Last year’s weather was dominated by two La Niña events. The first, one of the strongest in recorded history, began in 2010 and continued into the autumn of 2011. The second, weaker event, formed toward the end of winter.

Welcome to 2012, Weather Fans!

If weather is your thing, and wild, weird weather is even more your thing, then 2011 must have left you happy as a clam.. You must have been very busy keeping track of the rash of tornadoes, floods, fires, droughts, high highs and low lows that inspired climatologist Bill Patzert to call it “global weirding.”

It started out with the news that scientists had created 52 rain storms in the Abu Dhabi desert in 2010, and it just got weirder from there.  In the UK, the two-spring, no-summer year fascinating, but poor wildlife found it plain confusing. Animals all over the world suffered through the weird weather of 2011, with mass animal deaths making the news several times in 2011. (Remember when thousands of birds dropped dead from the sky in Arkansas, Louisiana and Sweden, millions of dead fish washed up in Chesapeake Bay and Brazil, and hundreds of dead crabs turned up in England?)

Meteorologists have offered scientific explanations for the weird weather that mostly point to La Niña and the North Atlantic Oscillation and to the Arctic Oscillation, but they are don’t all agree on the extent to which global warming is to blame.

They all agree, sadly, that we need to prepare for more weird weather. In an article on Nature.com, Quirin Schiermeier tells us the Intergovernmental Panel on Climate Change, (IPCC) warns that “it is ‘virtually certain’ — meaning 99 to100% probability in IPCC terminology — that the twenty-first century will see an increase in the frequency and magnitude of warm temperature extremes and a decrease in cold extremes.”

True to form, 2012 has started out with a springtime-like tornado in Texas, a winter-like, snowy summer in Australia, too little snow in Canada and too much in France, Austria and Germany, drought in Argentina and extreme heat in Africa.

Welcome to the wacky world of weather watchers. 2012 looks like it is going to be a wild ride for most of us.