3-year trends to September 2017

More arid

3-year climate trends to September 2017

September raw anomaly data (orange)

In September 2017 all moisture indicators except cloudiness showed even greater aridity (high up on the graphs) than in August. Daily maximum temperature anomaly (x-axis in all graphs) had now risen very high, but that of the subsoil (lower right graph) had fallen. Daily minimum temperature anomaly (lower left graph) remained extremely low.

 Fully smoothed data (red)

The latest fully-smoothed data point is that for March 2017.
At that time, the climate was warm and almost static, after a minor peak in aridity. Although later anomaly values (only partially smoothed) are subject to noise, three of them have raced away towards aridity: dew point fell, daily temperature range rose, and daily minimum temperature fell.


Note:

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.

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September 2016 had near-record rain

Blooms of Acacia paradoxa

Kangaroo Thorn

There were fourteen rainy days in a month that ended no warmer than it began. The month of September normally warms up by nearly four degrees. This time it remained near 14° all month. Some plants encouraged by the plentiful moisture were discouraged by the cold.
The highest daily rainfall reading, 28.8 mm on the 14th, hardly compares with one of 71.1 mm in 2005, or even one of 40.0 mm in 2011.
No days were warm. For the first time in this 18-year record, no September day reached 25°. More days than ever (18) were below 20° but not one was as low as 15°. Temperatures at night were near normal. A frost on the 5th was the only one. It may have been the last of the year, about a fortnight earlier than usual.
Only four mornings this month had no cloud, while seven were totally overcast.

Weather log for September 2016

Comparing September months

For monthly average temperatures, the daily maximum of 19.7° stands out as a record low, 4.1° below normal. Three indicators for moisture reached their extreme September values for the new century: rainfall, percentage of cloudy mornings (63%), and (narrowest) daily temperature range (12.0°). Dew point (6.0°) was just above normal, but very much higher than in September months since 2010.
The monthly rainfall total of 122.4 mm (amended) was one of the four highest ever September readings. The others were: 1917: 124 mm; 1949: 126 mm; 1998: 166 mm.
There are not now any noteworthy shortages in rainfall totals for any number of months, up to 360 months (thirty years).

Climate for September 2016


Data. Rainfall figures for this month are from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

3-year trends to September 2016

Parametric plots of smoothed climate variables at Manilla
“September 2016 extreme cold and rain”

Trends to September 2016

September raw anomaly data (orange)

September 2016 was extremely wet and had extremely cold days. Axes on the graph had to be extended to anomaly values of minus 80 mm for rainfall and minus four degrees for daily maximum temperature. In sympathy, cloudiness and dew point were extremely high and daily temperature range was extremely low.
On the first graph, partially-smoothed rainfall and temperature values had moved consistently in the same direction since March.

 Fully smoothed data (red)

The latest fully-smoothed data point is March 2016.
Rainfall, temperature range anomaly and daily maximum temperature had been static for three months. The latter had been rather high, the others normal. Cloudiness, dew point and temperature range had begun to move down the graph, while daily minimum temperature and subsoil temperature had begun to move up.


Note:

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.

September 2015 cold and dry

Photo of native clematis

Native clematis

Few days or nights in September were warmer than normal. The 23rd was a very cold day (17.1°) and the 24th had a very cold morning (-0.1°). The weekly temperature was near normal in the third week, but it had been cool in the first. It was cold (4.7 below normal) in the fourth week, and was rising through normal at the month’s end.
As is usual in September, most days were fine, and they were much warmer than the nights. The afternoon humidity was low (24%), but not nearly as low as in 2013 (15%).
Rain fell on only four days, with the highest reading 8.6 mm on the 4th.

Weather log for September 2015

 Comparing September months

In a dramatic change from August, both days and nights were very cold, as they were in September 2004.
The aridity was not quite as bad as in 2013, when the dew point was lower and there was less cloud.
Such cold, dry conditions are not those of an El Niño event (hot and dry) or of a La Niña event (cold and wet). If more extreme, they would be those of a glacial period.
The rainfall of 15.9 mm was well below average, in the 22nd percentile. There are still no serious shortages in rainfall totals for small numbers of months. A severe shortage (4th percentile) has appeared in the 30 month total (1186 mm). There are still deep ponds in Greenhatch Creek.

Climate for September 2015


Data. All data, including subsoil at 750 mm, are from 3 Monash Street, Manilla. Rainfall data up to 26/3/15 is from Manilla Post Office, Station 055031.

3-year trends to September 2015

Parametric plots of smoothed climate variables at Manilla
“September 2015: cold and dry”

Trends to September 2015

 

September raw anomaly data (orange)

September brought big changes in all raw values of climate anomalies, except for daily temperature range, which stayed rather low.
There was a sharp drop in temperatures: maximum, minimum and subsoil.
Moisture measures – rainfall, cloud and dew point – all fell.

These transitory values are unlike either the hot arid values of El Niño conditions in eastern Australia or the cold moist La Niña conditions. They are like a mild form of the cold arid conditions that are thought to have occurred in glacial periods.

 Fully smoothed data (red)

Fully-smoothed anomaly values for March 2015 continued the trends of late summer. Most moved further away from drought. Daily minimum temperature became static, and subsoil temperature began to rise.


Note:

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.

September 2014 cool and dry

Acacia decora hedge

A hedge of western golden wattle

The daily weather log

Two 5-day cool spells began on the 2nd and the 17th. Days and nights were both three or four degrees cooler than normal. At the same time, the air was very dry: a new lowest September dew point of minus 8.1° came on the 19th.
At other times, temperatures were near normal. There were four frosts (normally three). There were four rain days, which is normal.
The first thirty-degree day since mid-winter came on the 30th. At Manilla, it often comes near the spring equinox (September 22nd). In the 21st century, the first thirty-degree day came as early as August 23rd in 2009 and as late as November 9th in 2010.

Weather log September 2014.

 Comparing September months

Last September had been the warmest in this century. While not cold like September 2004, this month was half a degree cooler than normal. Like September in 2003, 2007, and 2012, it was both cool and dry. By contrast, the cool Septembers of 2010 and 2011 were wet, affected by La Nina.
Cloudiness and daily temperature range were near normal, but the mean dew point (1.4°) was not much higher than the extreme low value (0.6°) set last year.
The total rainfall of 18.8 mm is in the 26th percentile, well below the September average of 41 mm. Totals for periods of more than one month now have serious shortages for six months (7th percentile), nine months (7th percentile), and fifteen months (5th percentile), and a severe shortage for eighteen months (4th percentile).

The current drought report (6/10/2014) of the Bureau of Meteorology shows some serious and severe rainfall deficiencies in the area. Ten-month deficiencies extend west to Manilla from the Northern Tablelands, and there are 24-month rainfall deficiencies near Manilla and widespread around Walgett, 300 km to the north-west.

Climate September 2014.  


Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Temperatures, including subsoil at 750 mm, and other data are from 3 Monash  Street, Manilla.

3-year trends to September 2014

Parametric plots of smoothed climate variables at Manilla
“September 2014 had little rain”

Trends to September 2014

 September data (orange)

Most raw anomaly values for September remained on the cool-moist side of normal. However. both rainfall and dew point were again well below normal.

Fully smoothed data (red)

The latest fully-smoothed data (March 2014) continued the trends established in summer. All were moving away from drought, except for daily minimum temperature. That is, nights were becoming very warm.


Note:

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values are based on averages for the decade from March 1999. They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.