Another warm autumn, 2019

Lake Keepit very low

Keepit Dam at 0.9%

This season had a series of warm spells separated by normal autumn temperatures. The warmest, about 4° above normal, came in early March, late April and late May. Dry air came at cooler times, near the 1st of March and the 12th of April. Most of the rain came in two very wet days: the 30th of March and the 4th of May (61 mm).

Weather log autumn 2019

Comparing autumn seasons

As in 2018 and 2016, autumn was very warm. Although autumn 2016 had the highest mean temperature of the new century, this autumn had the warmest nights: 12.7°.
Despite the on-going drought, measures of moisture were near normal for the season. Cloudy days reached 37%, the daily temperature range (14.3°) was quite narrow, and the early morning dew point (7.2°) not low. The rainfall total, 117 mm (est.), was at the median value, not far below the mean of 134 mm.

Manilla clmate for autumn


Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available. Station 55312 recorded no readings this autumn. I used my own readings for the whole season.

All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Moist October 2018

Green grass in a drought

Greenness that thickens

No temperatures were extreme, but many nights were warm. The weekly temperatures were three or four degrees high after the middle of the month. The sunniest days had low early morning dew points.
There were eight rain days, with the highest reading 15 mm, on the 11th.

Weather log, October 2018

Comparing October months

While the mean temperature (20.3°) was just above normal, this month was as moist as October 2017. Despite the continuing drought, the daily temperature range was low (14.9°), the cloudiness high (52%), and the dew point high (7.2°).
The rainfall total of 51.6 mm (estimated) is at the 45th percentile for October, not far below average (58 mm).
I have reported the drought in another post (“Contours of Manilla’s 2018 Drought”).

Climate in October months


Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available.  The record was again defective in October 2018. No 9am readings were recorded. I have substituted my non-standard gauge readings for all days.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

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.

Rainy days in March 2017

March 2017 had 17 rain days. In 134 years, this was beaten only by June 1950, which had 18. [See Note below: “Manilla rain day statistics”]

Fronds of Acacia pendula

Weeping Myall

[Three years later, this post still gets hits. Perhaps people are sucked in by the title. I have added information and links, in case they really are interested in the topic.]

After the record high temperatures of February, day and night temperatures in March were normal, without extremes. On a weekly basis, the first half of the month was cooler than the second half. The subsoil temperature followed the weekly air temperature down, to be a degree below normal by the 20th.
The second week had mainly clear skies and low dew points, Then the skies became persistently cloudy and dew points were high. A number of afternoons had oppressive humidity, with minimum values over 70%.
Of the 17 rain days, only three were early in the month, and they had little rain. The highest daily reading of 15.0 mm came on the 22nd.

Weather log for March 2017

Comparing March months

March had been sunny and very warm in both 2016 and 2015. This March was like that of 2014 and 2013, but with even more moisture. The mean average temperature was normal but, due to the cloudiness (58% cloudy mornings), the mean daily maximum, 29.1° was low and the mean daily minimum, 16.4°, was high, yielding the record narrow daily temperature range for March of 12.7°. The mean early morning dew point, 13.7°, was the highest March value in a decade, and the mean afternoon humidity minimum, at 53%, was far above the usual value of 30%.
The total rainfall of 113.2 mm was at the 90th percentile, far above the March average of 54 mm. The previous month, February, had only 4.1 mm, at the 4th percentile for that month. Taken together the two-month total of 117.3 mm was well above normal, at the 63rd percentile.

Climate for March 2017

[Note: Manilla rain day statistics

The number of rain days in a month at Manilla reached 18 only once, in June 1950. Both June 2016 and this month, March 2017, had 17 rain days. This month’s high number is more remarkable, as March has only 4.8 rain days on average. Most months of the year have about six rain days on average, but the autumn months of March, April, and May have an average of 4.6 rain days per month. The averages are posted here.]


Data. In 2016, a Bureau of Meteorology automatic rain gauge (formerly used for flood prediction) was set up in the museum yard as the official Manilla rain gauge. From 23 May 2016, its daily readings were published as if from Manilla Post Office, Station 55031. The gauge ceased transmitting five months later, on 7 October 2016. This month, after repair, it came into operation again. From 17 March 2017, daily readings are now published as Manilla Museum, Station 55312.

In these reports,the rainfall data is from Station 55031 or Station 55312 when available. Otherwise, rainfall data is from 3 Monash Street, Manilla.  All other data, including subsoil at 750 mm, are also from there. 

July 2016 had a record warm night

Photo of a pond at sunset

A neighbour’s dam

The second cloudiest month of this century brought the warmest July night.
There were two very warm spells in the trace of weekly average temperature. Both were due mainly to warm nights. The second spell, coming in the third week, reached nearly six degrees above normal. On the morning of Saturday the 23rd, the minimum reading on the screen thermometer, 14.4°, was the highest July minimum in the record from 1999.
Up to the 25th, the weather was changeable, with some days overcast and rainy, and others fine and sunny. A very warm sunny day on the 17th, following a frost, had the unusually wide daily temperature range of 21.9°. From the 25th, the weather settled to what is normal for July. In the whole month, there were sixteen frosts, which is normal.
The highest rainfall reading was only 11.4 mm. Ten days had rainfall recorded, but three of these had 0.2 mm, on days when rain was not seen.

Weather log for July 2016

Comparing July months

The mean daily maximum temperature (16.9°) was normal. The mean daily minimum temperature (4.0°) was two degrees above normal, making the average temperature (10.5°) one degree above normal. Similarly, the subsoil temperature (14.7°) was one degree above normal.
The daily temperature range, normally 15.0°, was 12.9°, not quite as narrow as in 2010 (12.3°). The early morning dew point was normal. At 2.2°, it was so close the the daily minimum temperature (4.0°) that fogs were to be expected.
The month was extraordinarily cloudy. Cloud cover is assessed by the number of octas (eighths) of the sky seen to be covered by cloud at 9 am. I compare cloudiness of months by the percentage of “cloudy mornings”: those when I see more than four octas of cloud. This month, with 21 cloudy mornings, had 68%. July normally has only 35%. The only month in this century with a higher value was June 2013, with 73%.
The monthly rainfall total of 32.4 mm is below the average (41 mm), in the 47th percentile. The greatest rainfall “shortage” is now in the 48-month total (2221 mm) which is in the 14th percentile. Both Greenhatch Creek and Rushes Creek are just flowing.

Climate for July 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.