Weather Report February 2020

My one line takeaway for the month is quite damp with moderate temperatures.

The dampness manifests itself in both rain and morning humidity being above average.  Winds were quite modest in run, but rather surprisingly focused on the SE quadrant rather than the NW as was the case for most earlier months.

Rain

We finally got some!  The total fall for the month was 110.8 mm which is the 8th heaviest fall recorded for a February. That is of course comparing with BoM records and unusually this month was wetter at home than the BoM sites at Mallacoota (84.8 mm) and Gabo Is (78.2 mm).  The fall was well above well above last year and the median.

This means that my pro-rata extrapolation for the year in total is quite impressive currently standing at 1105 mm.

Temperatures

Overall the anomaly (the difference between the current average and the long term average for February - both calculated using BoM data) was 0.4^oC.  This is largely a balance between warm overnight temperatures (21 of 29 days had a warmer than average minimum) and cool daytime temperatures (19 days with a minimum below average).

Here are the daily maxima and minima.

Maximum temperatures

My Weather Station recorded an average maximum temperature of 25.1^oC a little above last year and the long term (mainly BoM) average.

The BoM average for the month was 23.2^oC: a little below average, as would be expected following my comments in the preamble to this section.  This is not unusual as the maximum temperature at the coastal BoM site is often moderated by a sea breeze kicking in around noon.

In Summer I look for heat waves - 3+ consecutive significantly above normal maxima.  Taking "significantly above normal" to mean greater than average maximum + 1 standard deviation, gives a threshold temperature of 28^oC.  In 2020 we did not record one such period: the 3 days from 23-25 February came close, with maxima of 30.6, 27.9 and 33.2, but the middle temperature prevented a cigar being awarded.

Minimum temperatures

The average minimum recorded at my Weather Station was 17.2^oC just above the highest average minimum of 17.15 recorded by BoM (in 2010).  This month the BoM average was 16.8^oC (although readings were not available for a couple of days, probably with warm minima based on readings at Gabo).  This is the equal second highest minimum recorded for February.

In view of the warmth of the minimum for 2020 I thought it worthwhile checking time series.  While a trend line in the time series (data available for February since 1994) shows a rising slope the value of r² makes it clear the 'trend' is not significant.

A much longer time series - reliable since 2010 - is available for Gabo Island.  That shows that the series varies considerably from year to year, but within a quite narrow band and with no significant trend.

Humidity

On a daily basis the month seemed to offer quite humid weather (duhhh - check the rainfall).

Looking at the monthly averages the morning value was well above the average and the value for last year.

 The afternoon reading was well above last years value but not much above average.

Wind

Although there were a few draughty days there was relatively calm.  In the next chart I have included a series titled "avg adjusted": this includes data from the BoM site adjusted by the ratio of the annual average wind runs at my weather station and the BoM site.  (My site is 45% of the BoM site.)  Somewhat rubbery, but gets values to the same scale.  On that basis February 2020 was less windy than the previous year (both measured at my site) and the adjusted average.

 As shown by the daily wind runs the winds were quite temperate other than the 23^rd when the hourly runs were close to 20km from midnight to 1400hrs. 

Checking wind direction at my site the modal direction was ESE.  This is similar to the situation in January but I feel somewhat different to previous months where the biggest direction was close to NW.  I am having difficulty in showing that.