Flangs plenty, hail none

The weather forecast for Mallcoota on 18 February suggested a high probability of some  rain and a chance (but less than 25% ) of a lot of rain in the early evening.

In the early afternoon the Weatherzone radar showed precipitation, and a lot of storm activity, in the centre of the State. The crosses show lightning strikes (giving rise to flashes and bangs hence "flangs").

 By 1538 hrs the system had moved East and the small cell over the Wingan was causing us to hear some rumbles.

Although the BoM severe thunderstorm warning did not at this stage extend to our area, bearing in mind the apocalyptic storm in Canberra a few weeks ago, we decided to rearrange a few things to get the Pajero in the garage.  That involved extracting the kayak trailer and putting the boats under the front veranda.

By 1750 the BoM warning included our area and the Weatherzone radar supported that view.

 At about the same time the Bairnsdale radar (which doesn't show lightning strikes as I am too stingy to pay for it) showed the line of weather approaching.

The storm arrived shortly after 1800 hrs with a long of spectacular forked lightning strikes touching down well up the valley.  I didn't try to take any photos as they were not that close together and the lag on a digital camera would make in impossible to capture a strike when seen.  A nice amount of rain fell and the gutters didn't overflow (a reward for cleaning them out on Sunday).

We ended with 7.6 mm at a peak rate of 85 mm.hr - circled in red in chart below.

No hail: but I'd rather that, than looking at a car with shattered glass!

Including a further 0.8 mm on the morning of the 19th we are now up to 97.2 mm for the month (the highest fall in February for BoM Mallacoota is 221mm in 2002). so we are 30 mm more than this date last year.  Doing a pro-rata expansion for the whole year gets us to 1167 mm.

Track opposite Pony Club

As there are no tapes or signs blocking off the bush track opposite the Pony Club we took ourselves for a walk along there yesterday afternoon.  A large tree had fallen across the track about 500m further in (the stump showed it to have had only a rim of wood, about 10cm thick supporting a 20m high trunk) and one looked a bit dodgy but basically the area seemed safe .

As we arrived a flock of 6 Yellow-tailed Back-Cockatoos dropped in: they were the only birds we saw on the outing.

The heath has been burnt but there is a good amount of regrowth happening.  The small trees here looked like an orchard!

Banksia serrata shooting from the base of the trunk: there were some very large Banksias along this track and hopefully more of them will regenerate.

 A small shrub - possibly some form of tea-tree.  I have enough trouble identifying these when they are in flower, let alone when just a bunch of leaves.

 A nice double-header Xanthorrhea resinosa (grass tree).

Some of the eucalypts were mainly green regrowth but others were this attractive bronze colour.  Possibly different species?

Against the cloudy sky the regrowth all appears monochrome!

 Gahnia sp (Spear grass) is beginning to hit its straps.

Looking across the Inlet as we drove down Karbeethong Ave it was apparent that the Howe Range has still got a bit of active fire.

Interestingly the Digital Earth Australia page shows no hotspots in the area (nor anywhere close)!

Another Bastion outing

The Lions Club went at it like beavers and have finished the steps.  An excellent bit of work

The beach had a fair amount of kelp washed up.  (Indeed up by the mouth it looked as though waves had broken over the bar.)

 A lot of soot/ash was still washing up.

 Te rain has caused the water level in the Inlet to rise, covering a fair proportion of the sand bars.

We came across a large (26 birds) group of Red-capped Plovers skulking in a shelly area by the mouth.

 One plover was down at the Inlet edge hanging out with a Red-necked Stint.

When looking out from Captain Stevenson's Point I noticed 2 Ravens investigating a lump on the beach.  On looking today I found the lump to be a former deer.  I'm less sad about a feral beast dying.

On Bastion today

The obvious sight as we walked on to the beach was the smoke from the fire in the Howe Range,  It has been re-stirred by a wind change.

The wind was also sending some nice waves on to the beach.

The Lions Club were also around the beach, rebuilding the steps.  This is a temporary - but professional arrangement to allow kids to get onto the beach.  Excellent stuff guys!

But if the kids get in the water, watch out for Bluebottles. 

Shorebirds were still around: Red-capped Plovers and Red-necked Stints were in numbers and accompanied by the first Ruddy Turnstone I have seen for a while,

A close up (and somewhat edited) photo of the Turnstone.

In plaves the sandbanks looked like a Fred Williams painting!

In others, a mess of ash.

These are - if I not mistaken - Deer footprints, coming from the direction of the campground

Heat waves in Mallacoota

In my recent weather report for January 2020 I commented on the number of heat-wave days in the month.  I thought it might be interesting to look back at the longer term picture of this type of weather.

To recap, the BoM defines a heat wave as:

3 or more consecutive days of temperatures significantly above average.  

I calculated the average maximum for each month and the standard deviation of the average and then defined the threshold for a heat wave as average +1SD.  I rounded these values down which makes a slightly lower threshold which compensates for the cases where there are 2 days above the threshold and the third is only 1 degree below.  This gave my temperature thresholds as >25^oC for November - March and I don't regard a temperature below 25^oC as worthy of being part of a heat wave.

The threshold values were:

In terms of perception of unpleasant weather the length of the heat wave is (IMHO) a significant contributor: a heat wave lasting 6 days is more than twice as unpleasant as a 3 day wave.  So rather than counting the number of heat waves count Heat Wave Days  which I define as a day that contributes to a heat wave.   Note that this can span the end of a month: a situation such as 30 Jan =30^oC;  31 Jan =30^oC; 1 Feb = 28^oC would count as a heat wave with 2 days in January and 1 in February.

Looking over the period of BoM records for Mallacoota (since 1994) the total number of HWD by month is shown below, which seems sensible.

 Looking at the total number of HWD for each Summer (eg 1994 represents the period November 1993 - March 1994) gives a jagged line which while appearing to have an upwards trend this is far below statistically significance.

I wouldn't want anyone to get excited about this statement as being an argument against climate change. 

1. It is a very short series;
2. The measure I have used may lack some rigour (eg is +1SD the correct measure to use in calculating the threshold?); and
3. The airport site often shows a much lower minimum than sites in town as the sea-breeze cuts in in the afternoon so may be biased to not record extreme temperatures.

However I think it is an interesting perspective.

The sun finally sets!

For most of the last week we have had fairly bad smoke haze, and for the last three days visibility was no more than 2 kms - at times well under 1 kilometre.  However on the afternoon of 2 February a South-West wind came in and blew all that muck away.  (It also seemed to stir up fire in the Howe Range but that is another story.)  This meant we could see both Mount Imlay and Nungatta Peak (both about 40km away in line of sight).

There was also a fair amount of cloud.   An outcome of those events was that we got a pretty sunset.

Two views from the road side of the house:

 And two from the Inlet side.

Weather Report January 2020

This has been a very difficult report to compile both from the view of having data to access and refraining from making excessive commentary on the data I have available.

A particular problem arose with the BoM site for Mallacoota not reporting for a total of 10 days, making it almost impossible to use that data for historical comparisons.  Fortunately my personal site kept running even though the console would have been running on batteries for 14 days.  Where at times my records appeared to conflict with those from the BoM sites at the airport and/or Gabo Island they proved very consistent with those from a private site in town which is linked to internet (as long as power is available!) and provides a better reflection of conditions in town than the airport site...

Clearly the month was very dry, with a storm on 20 January the only major fall.  Most of the month was relatively cool due to the smoke coverage keeping the sun off.  Late in the month this had the somewhat contrary "blanket effect" of holding the heat in giving very high minima.  Humidity was abut normal.  Wind strength was as expected although it was unusual to find a high proportion of the wind coming from ESE rather than nnw.

Rainfall

Pathetic.  A little more than last year, but still well below average.  The concentration of the fal into the storm on the 20th is clear in this chart.

The number of days with falls above 0.2mm was, at 9 days, surprisingly a little above average for the month.  (The average was taken from BoM  data since 1974 and excludes the period 1979 - 1984 inclusive where it was common to find the reading spanning several days.)

Temperatures

My usual overall measure of temperatures is the anomaly taken as the difference between the average for the reference period and the long term average.  That is made very difficult for this year as the BoM site was out of action for 10 days.  I thought of using Gabo Island as a proxy but that also failed to report for 5 days.  My conclusion to this was to calculate  the anomaly using the days for which the sites had a 2020 value available. 

 As well as calculating the anomaly I have plotted the recorded value for 2020 and the average for the day.  As Gabo has more days available I have shown that first.  Note that I truncated the vertical scale to show more clearly the comparison between the two series and not out of an IPA/Murdochian shokanorror desire to panic people.

Looking at the charts it is not surprising to find that the anomaly for Gabo (+1.3^oC) is greater than for Mallacoota (+0.2^oC).   I believe this can be attributed to the skies at Gabo being less opaquely smothered in smoke.  For an assessment of comparison with long-term trends (who said "Climate Change"?) I believe the value for Gabo is a more useful indicator than that for Mallacoota.

A second approach to overall temperatures is to look at the daily extremes through the month.  These data are from my Weather Station.

I was quite surprised at the fluctuations.

Maximum temperatures

The highest temperature recorded at my WS in the month (38.0^oC) was on the 31st while the BoM site got to 34.9 on the same day. I plotted the maxima at my WS against those available from BoM:

 As expected my WS readings are higher than the BoM data (exaggerated by the truncated scale) due to the sea breeze kicking in in the afternoon.  However I believe that the long term average data for the BoM site provides a useful background for comparison on current values and in the chart below the 2020 value is from my WS while the other 2 values are BoM.  (From March onwards the 2019 value will also be from my WS.)

Of course, for refuting the views of climate change denialists (if anyone still espouses such views after this Summer) the argument will always be mounted using only the more consistent information from BoM.

The other interesting aspect of maximum temperatures in Summer is that of heat-waves.  The BoM defines a Heat Wave as 3 consecutive days of significantly above average maximum temperatures.  Taking this to mean the long term average maximum plus 1 standard deviation gives the lower limit for a heat wave in January of 25.1^oC.  My indicator statistics is number of Heat Wave Days HWD in a month - that is counting the number of days that contribute to heat waves in the month.  For 2020 there were 8 such days (including the 30th and 31st (both over 25.1^oC as was the 1st of February)!

I shall do an analysis of the cut off temperatures for other months and thus a time series of HWDs.

Minimum temperatures

The month concluded with an extremely warm minimum on the 31st (BoM 22.9^oC, WS 23.1^oC).  The BoM reading was the 4th highest on record (stealing February's thunder: the value (24.0^oC) on 1st February equalled the all time high minmum for Mallacoota).

The BoM and WS values were very close.

 This year's average minimum was a bit above average but less so than 2019.

Humidity

The daily numbers especially for 1500 hrs, vary greatly though the month.  RH of close to 40% is very low for a coastal site.

 The morning value was higher than 2019 and the historic BoM average.

 The afternoon value was a touch under average and considerably below the value for 2019.

Wind

The average daily run was 137 km which is reasonably high when compared with other values for my WS.  The little data on wind published (at no cost) by BoM suggests it is of a broadly correct order of magnitude.

The wind rose is interesting in showing a high proportion of wind coming from the ESE, rather than the more usual NNW - N section of the rose.

An initial review suggests the wind mainly came from this direction for the period 17th to 29th.  The very hot weather of the 30th to 31st reflected a return to N winds.