Weather for the month of April 2008 at Blacktown:
I will post a run down of the April 2008 weather experienced at Blacktown where I live. The month of April 2008 can be summarised as being significantly cooler when compared to recent years. In particular:-
a) There was 1 thunderstorm on the 13/4/2008.
b) It rained on 14 days (That represents 46.6% of days when it rained). The majority of that fell in the form of showers rather than rain periods.
c) There were 3 fogs. The number of fogs this year is rather high.
d) There were 10 days in which the maximum temperature failed to reach 20 degrees Celsius. That is 33% of days during the month of April failed to reach 20 degrees Celsius. This is very significant. In April 2006, the temperature on every single day exceeded 20 degrees Celsius and during the same month, it reached 30 degrees on 5 such days. In April 2007, the temperature failed to reach 20 degrees Celsius on only 4 days but it did not reach 30 degrees once.
Average maximum temperatures were 21.69 degrees Celsius and the minimum was 11.7 degrees Celsius (BOM 2008 for Prospect about 3 km away). My figures vary slightly being 21.4 Celsius and the minimum being 11.5 degrees Celsius. Compare that to April 2006 where the average maximum daily temperature was 24.6 degrees Celsius and the minimum was 10.03 degrees Celsius. Compared to 2007, the average maximum temperature was 23.5 degrees Celsius and the average minimum was 12.8 degrees Celsius (Note 2006 was an El Nino year).
Thus the daytime temperatures for April 2008 have been significantly colder than in recent years (For this month) but night time temperatures were OK.
Off course the minimums of 4.5 C and 4.8 C on the mornings of 29 and 30 made things feel colder. Then again, a minimum of 2 degrees occurred on the morning of 23/4/2006 so the coldest April minimum of 2008 was warmer than the coldest April minimum of 2006.
e) Rainfall:- There was around 68 mm of rain. However, the official nearest rain gauges at Seven Hills shows 83 mm and Prospect shows 79.9 mm. This is a big variation. This can be largely accounted for a thunderstorm on the 13/4/2008. When analysing rain gauges from that, the storm intensified just to the east of Blacktown and rainfalls 1 to 2 km away to the east were significantly heavier (more than double the 6 mm that fell). This explains the variation.
Not specifically to Blacktown, rainfalls across Sydney showed very large variations during the month (BOM). The wettest areas include:-
Riverview 172 mm, Avalon 171 mm, Turramurra and Belrose 167 mm each, Gordon West and Canterbury 163 mm each, Marsfield 149 mm, Sydney 147 mm, Rose Bay 137 mm and Randwick 135 mm.
The driest areas include Glenmore Park 48 mm, Badgeries Creek 51 mm, Glenorie 65 mm, Prospect 79.9 mm, Seven Hills 83 mm and Bankstown 84 mm.
Some rainfalls were below average and some were above average.
The colder than normal temperatures, cool cloudy and showery days are repeated right across Sydney and this is in stark comparison to 2006. April 2006 shows one extreme during an El Nino year in which April was overall dry and warm (3 mm of rain fell on 2 days) but April 2008 shows another during a La Nina year where it was cool and it rained on 14 days that produced moderate to high rainfall totals. April 2006 and 2008 provide interesting comparisons between an El Nino and La Nina year.
Harley Pearman