Friday, 2 May 2014

April 2014 Weather

Before getting to the actual weather report may I share with you a bit of philosophy or such like?

This arose from a recent Country Mouse column in Country Life magazine in which Mr Hedges referred to the old English saying:
Oak before Ash,
we'll get a splash.
Ash before oak,
we'll get a soak.
When I was growing up in Essex there were several of these folk weather forecasting verses around.  In the US the only one I was aware of was Groundhog Day.  In Australia I'm not aware of any such traditions in European culture,  with such lore as does exist being calendar based (eg plant garlic on the shortest day, harvest it on the longest day; start seeding cereals on ANZAC Day).  While in Darwin an indigenous colleague did comment that the appearance of lots of dragonflies meant the end of the Wet was near so possibly their cultures have much material of this nature.

It has been suggested that by the time of European settlement occurred in Australia popular reliance on written calendars had replaced forecasts derived from natural observations.  I may return to this topic in a later post.

Autumn is with us.
Perhaps I should develop an adage "Pistacchio goes gold, nights be cold" followed with a few gaffery mutterings and expectorations.  Nah: lets use the data from my weather station.

Rainfall

The good rains of this year continued through April.  We recorded 69.8mm, the highest I have done in this month since we have lived here.  While 4 days were only 0.2mm (and thus most likely condensing fog), 3 events contributed more significant falls on 7 days.
My observations of flows in Whiskers Creek suggest that a lot of this moisture soaked into the ground, rather than running off.  This have meant the countryside is now nicely green (apart from the bits covered with attractive fungi).

Temperature

This needs a little explanation before getting to the interpretation.  
  • The green lines represent the range of temperatures during the day with (obviously) maximum at the top and minimum at the bottom;
  • The yellow boxes are days in which the temperature at 0:30hrs (bottom of the box) was cooler than the temperature at 23:30hrs (top of the box);
  • The blue boxes are days in which the temperature at 0:30hrs (top of the box) was warmer than the temperature at 23:30hrs (bottom of the box);
  • A dash crossing the vertical line means 0:30 and 23:30 temperatures were the same.

Interpretation

After a relatively warm first three days the maximum temperature dropped below 20oC and stayed there more or less constantly for the rest of the month.  While 26 days recorded a minimum below 10oC, only 2 were below 2oC and none below zero.  As suggested by the blue box on the 30th, the temperature settled down for more wintry levels on that day.

Humidity

A fairly stable month.  As shown by the 0700 hours line most days began with mist or fog with the outdoor rH being over 90%,  During the rainy period the humidity was high for the 1700 hours reading and only on one day did it drop below 40% .

Wind

As usual the wind data should be approached with caution as my anenometer is mounted much lower than official meters.

This first graph shows the maximum wind gust record each day as well as the average of maximum gusts recorded in each 30 minute period (if that makes sense to you).
This is about a "normal" level of windiness.  This is illustrated by a comparison of average gusts for March and April 2014.  In both months the average is between approximately 3 and 6 km/hr on most days.

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