Interesting Matthew. A result of the rain, one would think,
might be a higher than usual influx of cockatoos to feed on the local weed
growth. However that might depend on conditions elsewhere, and I notice that
the archive shows patchiness in that regard. For example Grenfell and Gundagai
had ‘very high’ rainfall in April, but at most Riverina sites eg Griffith and
Hillston there was only ‘average’ rain. ‘Average’ seems to be as low as
anywhere got.
From:
[
Sent: Tuesday, 5 May 2009 12:06 PM
To:
Subject: [canberrabirds] FYI: Monthly Climate Summary for Canberra -
April 2009 [SEC=UNCLASSIFIED]
With climate
being such an important factor in our bird population, the following is
provided for the information of subscribers (and as an addition to the annual
summary provided in the Annual Bird Report):
http://www.bom.gov.au/climate/current/month/act/summary.shtml
Canberra has wettest April since 1990
· Above average rainfall, the highest
for April since 1990
·
Close to average maximum temperatures
·
Well above average minimum
temperatures, highest for 11 years
·
Coldest consecutive 5 days in April
since 1952
Rainfall
Following very dry conditions in February and March, some welcome rain was
recorded over the ACT during April. Canberra Airport recorded its wettest April
since 1990 with a total of 71 mm, compared to the historic average1
of 46 mm. It is also the wettest Autumn month in Canberra since May 1995, which
goes against a recent trend of dry Autumns in the ACT. Tuggeranong recorded
considerably higher rainfall with a total of 99 mm for the month and Mount
Ginini in the Brindabella Ranges recorded 140 mm. There were 10 rain days at
Canberra Airport during the month compared to the historic average of 7 rain
days. Active low pressure troughs on the 3rd, 14th and 26th were responsible
for most of the rain.
Mount Ginini had the Territory's highest April total of 140 mm while
Kingston recorded the lowest total of only 67 mm. The wettest day was 42.0 mm
at Deakin West on the 14th caused by a low pressure trough.
Temperatures
Daytime temperatures were cool to mild in the ACT during April. Canberra
Airport recorded an average maximum temperature of 19.6 °C, which is 0.4 °C
below the historical average of 20.0 °C. Daily maximum temperatures reached the
low 20's for most of the month except during the last week when a cool change
brought much colder weather. Canberra Airport recorded 5 consecutive days (25th
to 29th) with a maximum temperature below 15 °C, the longest cold spell for
April since 1952.
The below average daytime temperatures were partly due to prevailing S-SE
winds, especially during the mornings and the partly cloudy, showery weather.
Overnight temperatures were quite mild. The average minimum temperature at
Canberra Airport was 8.4 °C which is 1.8 °C above the historic average. This is
the highest average minimum temperature for April since 1998. The minimum
temperature on the warmest night was 15.1 °C both on the 1st and 2nd. The minimum
temperature on the first 3 days of the month exceeded 14.5 °C, which has not
occurred over 3 consecutive days in April since 1989.
Temperature extremes at Canberra Airport ranged from a high of 28.6 °C on
the 3rd to an overnight low of 1.8 °C on the 29th. The lowest temperature in
the ACT was -5.0 °C at Mount Ginini AWS on the 29th following a strong cold
front.
Wind
S-SE winds prevailed over the ACT during April for 50% of the time during
the mornings which is more than twice the normal frequency from this direction.
There were 2 windy days recorded during the month associated with westerly
winds. The highest wind gust was 96 km/h from NNW at Canberra Airport on the
24th associated with the passage of a cold front, the strongest winds in April
since 1993. The more exposed mountains to the SW of the city recorded wind
gusts of 100 km/h from the northwest at Mount Ginini AWS on the 25th.
Other phenomena
Cloudy days prevailed in the ACT during April. A total of 14 cloudy days
exceeded the historic average of 9 cloudy days. Sunshine averaged 7.1 hours per
day, a little below the historic April average of 7.3 hours per day. There were
3 thunderstorms reported at Canberra Airport during the month, on the 3rd, 11th
and 14th. Widespread raised dust on the 15th reduced visibility to only 4 km
over the ACT. The dust originated over western Victoria and southern NSW and
was caused by the combination of strong westerly winds and persistent dry
weather over southern inland NSW. At least 10 cm snow fell on the mountains to
the SW of Canberra from 26th to the 28th following the passage of a cold
front.**********************************************************************
IMPORTANT: This e-mail is intended for the use of the addressee and may contain
information that is confidential, commercially valuable or subject to legal or
parliamentary privilege. If you are not the intended recipient you are notified
that any review, re-transmission, disclosure, use or dissemination of this
communication is strictly prohibited by several Commonwealth Acts of
Parliament. If you have received this communication in error please notify the
sender immediately and delete all copies of this transmission together with any
attachments. **********************************************************************
