Saturday, 5 April 2014

March 2014 Pretty soggy Weather report

Not that I - nor anyone else in the area is complaining (yet).


I have done a separate post assessing the performance of the Bureau of Meteorology in forecasting the rain event late in the month.  Basically they done very good.  I have commented previously January 2013) in a favourable way and in December 2012 less favourably.  Possibly this is an instance of that well known statistical maxim "If tomorrow turns out much like yesterday forecasting ain't too hard".

We ended up with recordable moisture (some of it may have been condensing fog) on 15 days with 5 days over 5mm.  The total was 72.4mm.  In comparison with the past (especially 2013) I'd rate that as excellent.
(Ignore the value for April, other to observe that 3.5 days into the month we're above last year and almost up to the 7-year average.)


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.


Basically a very temperate month: no maxima above 30oC and no minima below 5oC.    11 days got above 25oC  and 12 below 10oC .

It is of interest to me that for several days the box is both very small and at the bottom of the line.   That coincides with days in which the morning was very foggy and the fog has insulated the low air , rather than allowing the heat to continue to escape until the sun warmed it up.


In contrast to recent months the significant feature here is the 'bottom line' relative humidity of 40% which my hydrologist friend Stephen regards as a 'reasonable' value.  There were only 6 days in March on which the 1700Hrs rH was below that value.  In contrast in January 2014 the 1700 rH was below 40% on 21days and in February 2014 on 17 days. 

The spectacular rise on 23 March reflected the trough settling in to bring rain.


As always, I find it difficult to grapple with how to display the wind to demonstrate the basic information about the month.  I suspect that this is in part due to the station being positioned 2m, rather than 10m above ground level and thus giving rather unexpected results.  (Or perhaps I am being rcalcitrant in admitting to myself that my expectations are naff?)

The graph of wind speed this month shows the maximum gust for the date as a whole, and the average speed of the gusts in each 30 minute period.
As should be expected the line for maxima is more variable than that for average.  My impression is that for a month containing an equinox it wasn't very windy.

In terms of wind direction, the maximum gusts tended to come from ENE to SSE.  This is 38% of the circle, but covers 61% of the gusts.

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