"Chookie" wrote in message
...
In article ,
"Farm1" please@askifyouwannaknow wrote:

Just very qucikly as I have to go and do somethign about dinner. I
think you need to consider trends and variations from the averages.
For example the trend has been for lower rainfall in many parts in Aus
for at least a 30 year period - SW WA is one area where the trend has
been downward in that time. Averages are just that over the lifetime
of rainfall records and we cna be up or down from that in any one
year.

The BOM uses a 30-year average, I think. Yes, it was the variance I was
interested in, not the mean.

afair, the 40s & 50s were "unusually" wet in aust (compared to prior to
that) but in some people's minds that would have become what is an
"average", or what you could "expect". but it's been drier since then - that
was "unusual".

the famous "federation drought" & such, well - i don't know. at that point
people hadn't been keeping records for all that long, so frankly it makes me
wonder if our rainfall has not _always_ been compared to england or ireland,
and to do so would clearly make almost any year a "drought" :-) i think it's
only recently there have been records kept for consistently long periods
that you can get a real overview, but that's jmo. i just think that in
term's of the earth's life & overall patterns, 100 years is nothing, really.

One change I've noticed is that back in the Old Days, highs and lows would
head up out of the Bight and drift in an arc across NSW. Now, they aren't
centred on the Bight and the arc takes them up into southern Qld. That
pulls
more monsoon rain into Central Australia, but leaves the south-east of the
continent drier. Not sure if this is part of El Nino or separate.

el nino is still operating. the Powers That Be (weather nerds) expect the
effect to have passed by april or so, & for rain to return to "normal". i am
however not really sure there's ever been any agreement about what is
"normal"!! :-)

what is "normal"? the other day we were in town & a storm passed through -
it rained 35mm in about 1/2 hour. at our place, we got less than 2mm. the
difference is only about 12km as the crow flies. it regularly rains at our
place but not at the end of our road (or vice versa).
kylie