As July draws to a close the Australian current month to date rain percentages bear little resemblance to the July rain Outlook.
As our commenter has reported – now August is here we can see the BoM max and min anomaly maps for July and you can compare to the way-way hotter looking 25th June Outlooks for July max and min.
ECLs are unpredictable, but not unusual in July. I’ll give BoM a bit of slack on this.
No significant rain over any of Oz right now on radar.
The forecast for central Vic looks fairly close but over large areas of the rest of the country it’s way off!
For my place in SE Qld the prediction indicating 50% chance of normal rain and the cumulative chart which indicates 100% of normal rain are both wrong. In fact my measurements (daily) show 161.4 mm which is double the 127 year average of 80.5mm.
There was flash flooding in Brisbane and the gold Coast. Some places had 100mm in one day. We had 84mm over 4 days from 23rd to 26th (inclusive) with no flooding anywhere in surrounds.
BOM seem not to be able to look out of the window and see the rain falling.
Max and Min Temperature anomaly maps are now out for July and both are way-way cooler than the crazy exaggerated max and min Outlooks for July produced in June that are both too hot.
I’ve been using two separate weather update programmes on both my mobile and laptop for about 20 years now. One is the BOM programme, the other is a 3rd party programme that reports information from differing global sources. I have both in 7 day forecast mode.
Two observations, based on almost daily use for decades:
with both programmes, the forecast temperature range and wind velocities are reasonably accurate (+/- 1-2 C, +/- 5 kmh). It is noticeable however that the BOM temp forecast some days out is *always* quite higher than the other forecast. On the day, both programmes are generally reasonably close
in forecasting rain, the BOM programme is no better than tossing a coin (literally true – I’ve often amused myself by testing this). The 2nd program has a success rate of about 65%.
For what it’s worth, that’s a daily record test over a long period.
Ianl rainfall is not completely random (ie 50% success). It occurs in daily groups which could be two days or even over 14 days. I would suggest that BOM should have a success rate of around 75% if a) they look out the window and forecast the next day to be the same as what they see outside and b) note the weather (radar, barometric pressure) to the west and make appropriate adjustment.
cementafriend
Agreed.
The average of daily results (ie. no better than a coin toss) surprised me too. I just employ your decribed method if rain or not is important to me on the day.
Interesting!
The 62.8mm recorded at Albany Airport weather station so far today has broken the all-time August daily rainfall at the site. The previous record was 50.8mm set on August 2, 1992. (Albany Advertiser).
Thanks John for that news from Albany.
BoM August rain Outlook issued a few days ago on 30th July Shows a rain deficiency for the Albany region. How quickly BoM guidance turns to dross.
Beachgirl
Where I live in the Northern Rivers (NSW, District 58) mean max temps were below average. But the map shows our district as above average. In other words, the anomaly was adjusted up to show even more warmth than there actually was. Others may like to check their district against the raw data and the adjustments from the monthly summary below.
www.bom.gov.au/climate/current/month/nsw/summary.shtml
The June Outlooks were light years from glory too – well worth a look. That makes a trifecta of May-June-July all duds.
Record cold morning daily minimum at LIAWENEE 096033 in Tasmania.
Tasmania has recorded its coldest ever day since records began of -14.2C as the rest of the eastern states are warned to prepare for heavy rain and cold temperatures this weekend.
The Bureau of Meterology labelled this week’s weather as ‘a very significant event’, and beat the state’s previous record of -14C in 1983.
www.dailymail.co.uk/news/article-8602325/Cold-weekend-Tasmania-records-coldest-day-mercury-plunged-14C.html
www.bom.gov.au/climate/dwo/IDCJDW7027.latest.shtml
Sure smashed the old record
www.bom.gov.au/cgi-bin/climate/extremes/daily_extremes.cgi?period=%2Fcgi-bin%2Fclimate%2Fextremes%2Fdaily_extremes.cgi&climtab=tmin_low&area=tas&year=2020&mon=8&day=6
www.bom.gov.au/climate/averages/tables/cw_096033_All.shtml