3-year trends to October 2017

Avoiding drought

3-year trends to October 2017

October raw anomaly data (orange)

October 2017 was moist: all moisture indicators had dropped sharply down the graphs, retreating from the aridity of August and September. Daily maximum temperature anomaly (x-axis in all graphs) fell towards normal, while that of the subsoil (lower right graph) remained low. Daily minimum temperature anomaly (lower left graph) jumped from extremely low to extremely high.

 Fully smoothed data (red)

The latest fully-smoothed data point is that for April 2017.
At that time, the climate was warm and almost static. There was a pause in a drift towards aridity.


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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October 2016 was cold

Photo of the bark of a Eucalyptus tree

White Box at Sunset

In this month, each of five sunny spells of normal temperature was followed by a cold, cloudy, humid break, generally with rain. Only a few days were warmer than normal, including the 27th. That was the first 30° day of the season, five weeks late.
The average weekly temperature was persistently three or four degrees cooler than normal. One cold week about the 15th was more than five degrees below normal, and the warmest week, about the 29th, was still half a degree low.
Most nights were very cool. I recorded no frosts, but others may have done. My most recent frost was early in September.
There were six rain days, not counting two readings of 0.2 mm. The highest reading was 20.0 mm on the 23rd.

Weather log for October 2016

Comparing October months

This was the coldest October on this record from 1999. That includes not only the maximum, mean, and minimum air temperatures read in the Gill Screen, but also the subsoil temperature at 750 mm. Noting that October 2015 had the highest October temperatures, the sudden collapse is astonishing. Last October was three degrees warmer than normal; this month was almost three degrees colder than normal. Put another way, the seasonal warming is a month late this year and was a month early last year.
Unlike September, there was not an unusual amount of moisture in October. Humidity, cloudiness and daily temperature range were near normal.
The monthly rainfall total of 72.1 mm was above the average of 58 mm, in the 70th percentile.
I have discussed the current drought status (that is, drought-free) in another post.

Climate for October 2016


Data. Rainfall figures are usually from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. However, the gauge ceased recording on the 8th of October, and later readings are from my non-standard gauge. All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

3-year trends to October 2016

Parametric plots of smoothed climate variables at Manilla
“October 2016 still cold”

Trends to October 2016

October raw anomaly data (orange)

In October 2016 daily maximum air temperature continued extremely low. Now daily minimum air temperature and subsoil temperature (bottom graphs) also became extremely low. Most other variables returned to near normal.

 Fully smoothed data (red)

The latest fully-smoothed data point is April 2016.
By then, most anomalies were moving definitely towards cool and moist. However, daily minimum temperature and subsoil temperature were rising.
In April 2016, the smoothed anomaly of daily minimum temperature was extremely high. It was approaching the 18-year record value of +1.32°, set in December 2009.


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.

October 2015 very warm

Photo of native jasmine

Sweetest Jasmine

The first 30-degree day of the season came on the 3rd. That was ten days late, but the first 35-degree day followed soon after, on the 6th. Most days and nights were warm through the month, and the weekly mean temperature was three or four degrees above normal until the last week.
Ten sunny days were followed by days with much more cloud, and four rain days (usually seven). On the 22nd and 23rd, I recorded 17.4 and 8.0 mm.

Weather log for October

 Comparing October months

This was the warmest October of the new century for all daily temperatures: maximum, mean and minimum. The mean temperature of 21.7° was 3° above average, and much higher than in the other warm Octobers of 2014 (20.6°) and 2007 (20.4°).
The graph shows the curious fact that October months have warmed steadily since 2011. Since 2012, Octobers have not become drier: rainfall, cloudiness and humidity have increased rather than decreased.
The rainfall of 35.0 mm was below average, in the 29th percentile. As in last month’s report, there are no serious shortages in rainfall totals for small numbers of months. The only serious shortages are in the 30 month total (6th percentile) and in the 42 month total (7th percentile). There are still deep ponds in Greenhatch Creek.

Climate for October 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 October 2015

Parametric plots of smoothed climate variables at Manilla
“October 2015: very warm”

Trends to October 2015

October raw anomaly data (orange)

After a cool September, October was very warm: the warmest of the new century in both daily maximum and daily minimum. The daily temperature range was also high, but the soil temperature was not. Rainfall remained rather low, while cloudiness and dew point were near normal.
[The recorded anomaly values for daily maximum and for daily minimum were +3.2° and +2.2° respectively. For convenience, I have plotted them 0.2° lower.]

 Fully smoothed data (red)

In the latest fully smoothed data (April 2015) all trends on the first four graphs continued to move steadily away from drought. The daily minimum temperature anomaly began to rise, and subsoil temperature rose faster.


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.

October 2014 hot and dry

Blooms of Melia azedarach

Fragrant white cedar blooms

The month began with a warm spell, which was followed by a cool spell about the 15th. It ended with a long hot spell, 4.8 degrees above normal, including the hottest October day this century (38.1°) on the 26th. As usual, there were no frosts.

Of three rain days (usually seven), only the 14th had much rain: 26.4 mm, with heavy showers.
Half the mornings had no cloud at all, and nine days had very wide temperature ranges, greater than 20°.

Weather log October 2014

 Comparing October months

This was the hottest October month at Manilla in this 16-year record. Maximum, mean and minimum temperatures were all highest values, but the maximum was no higher than in October 2007. The subsoil temperature returned to a value below normal.
As indicators of low moisture, the daily temperature range was very high and cloudiness and dew point were very low, as in the last two October months. Even less cloud had been seen in 2002 and 2004.
Recently, lower rainfall occurred in October 2002 (15.0 mm), 2012 (12.6 mm), and 2013 (15.0 mm). However, this month’s total of 27.0 mm is well below the October average of 58 mm, in the 21st percentile. Since last month, little has changed in rainfall totals for periods of more than one month. There is still a serious shortage in the 6-month total (8th percentile) but not now in the 9-month total (10th percentile). The 15-month total has advanced to severe (4th percentile), while the 18-month total has retreated to serious (5th percentile). A serious shortage has also appeared in the 30-month total (8th percentile).

Climate October 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 October 2014

Parametric plots of smoothed climate variables at Manilla
“October 2014 droughty”

Trends to October 2014

October data (orange)

All raw anomaly values for October, except subsoil temperature, moved suddenly to drought: high temperatures and little moisture. Subsoil temperature, which had been at a record high value fifteen months earlier, became very low.

Fully smoothed data (red)

The latest fully-smoothed data (April 2014), like that of the previous month, continued the trends established in summer. All (except daily minimum temperature) moved away from drought. A movement back towards drought came only later.
Since the major “flooding rains” episode of summer 2011-12, (lower left corner on the graphs)  Manilla’s climate has swung towards drought three times:
(i) a very mild drought in October 2012, returning to normal by March 2013;
(ii) a moderate drought that was very hot in October 2013 and dry in January 2014, returning to normal about May 2014;
(iii) perhaps a further drought about October 2014 (to be identified later).


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.