Dry September 2019

Striped Honeyeater at the Window

Weekly average temperatures increased slightly, as is usual in September. Unusual day temperatures came early in the month. The first 30-degree day was 18 days early, on the 5th. The next day was the hottest of the month, at 31.9°. During the next 3 days the daily maximum temperature fell by 16.9° to 15.0°, the coldest day of the month. Later, temperatures stayed closer to normal. There were 4 frosts, the usual number.
At the Manilla Museum, 1.2 mm of rain was recorded on the 23rd.

Comparing September months

The last three September months have all been dry, with low dew points, wide daily temperature ranges and not much cloud. They have not been nearly as hot as September of 2013, however.
The rainfall total of 1.2 mm is the 3rd lowest September reading, after 0 mm in 1980 and 1 mm in 1925. By way of contrast, the second graph also includes the deluge of 122.4 mm in September 2016, the 4th wettest on record.

Drought

I will report separately on the on-going drought that continues to break low-rainfall records at durations of 15-months and longer.


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. Recording resumed on 20 July 2019.
My estimates of early morning dew point have drifted anomalously low. From August 2019, I use data from the Tamworth Airport published graphs.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

3-year trends to August 2019

Summer record hot-dry (as smoothed)

3-year climate trends to August 2019

August raw anomaly data (orange)

Temperatures

Daily maximum temperature anomaly (all x-axes): near the maximum for smoothed values.
Daily minimum temperature anomaly (lower left): near normal.
Subsoil temperature anomaly (lower right): very high.

Moistures (moist is at the bottom)

Rainfall anomaly (upper left): very low.
Cloudiness anomaly (upper right): normal.
Dew point anomaly (middle left): low, like the other recent values.
Daily temperature range anomaly (middle right): very high.

 Latest fully smoothed data (red), summer 2018-19

Temperatures

Daily maximum temperature anomaly peaked at a record +1.79° in January.
Daily minimum temperature anomaly held the record vaue of +2.16° through January and February.
Subsoil rose rapidly from normal.

Moistures (moist is at the bottom)

Rainfall smoothed anomaly peaked negative in January at the record value of minus 31.75 mm per month.
Cloudiness was normal.
Dew point was low.
Daily temperature range was normal.


Notes:

January data points are marked by squares.

Smoothing Continue reading

Dry August 2019

Blossoms on a street tree

August Blossoms

Weekly average temperatures steadily increased as is usual in August. Day and night temperatures also were not far from normal. The warmest day reached 27.1° and the coldest night -1.4°. There were 15 frosts, the usual number.
Rain was recorded at the Manilla Museum on the 1st (1.0 mm) and the 12th (4.6 mm).

Weather log august 2019

Comparing August months

This dry month was very like August 2013, with the August months between being mainly rather cooler and wetter.
The mean maximum temperature (20.9°) was above normal by 1.4°, and the mean minimum temperature (3.3°) was near normal. The resulting temperature range (17.6°) was high, agreeing with the rather low cloudiness (26%) and dew point (-1.0°).
The rainfall total of 5.6 mm is at the 8th percentile for August.

Climate for August 2019

Drought

I have reported separately on the on-going drought that continues to break low-rainfall records at durations of 15-months and longer.


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.  No 9 am readings were recorded from August 2018 to 19 July 2019. Recording resumed on 20 July 2019.
My estimates of early morning dew point have drifted anomalously low. From August 2019, I use data from the Tamworth Airport published graphs.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Hot and dry records in January 2019

In January 2019, the smoothed anomaly value of monthly rainfall reached a record low (-31.8 mm/month), and that of monthly mean maximum temperature a record high (+1.79°).

Rainfall and temperature trajectory Sep2016 toFeb 2019

[This graph is extracted from a forthcoming post in the series “3-year trends…”. ]

This graph shows temperature and rainfall anomalies, not raw data. It shows how far the actual values differ from normal. The 30 data points from September 2016 to February 2019 (coloured red) are smoothed to show only cycles longer than one year.

The earliest data point, September 2016, had temperature and rainfall just beyond the normal range on the cool and wet side (lower left). Since that date, all the smoothed data points have fallen close to the sloping Mackellar trend line (blue) from cool-wet to hot-dry. (See the note below: Mackellar trend line.)
In the 4 months up to January 2017, warming and drying was rapid, passing completely through the “normal” range. Next, some cooling and wetting occurred to May 2017, then warming and drying resumed to a full drought in March 2018. Through the year 2018, drought prevailed, with a rainfall anomaly always below -25 mm. The temperature anomaly fell to only +1 deg by August, but rose again while rainfall fell. Records for low rainfall and high temperature were broken repeatedly.
January 2019 had the lowest smoothed monthly rainfall anomaly of the 21st century (-31.8 mm/month), and the highest monthly mean maximum temperature (+1.79°).
The following month, February 2019, had a slightly decreased temperature anomaly, and an increased rainfall anomaly. Later data points with less smoothing applied suggest that the smoothed record values of January may stand for some time.


Note.

Mackellar trend line

The insight of Dorothea Mackellar that this is a land “of droughts and flooding rains” *
is expressed in these graphs by a blue trend line passing through the “Normal” point in the centre (aqua) and extending both to “Droughts” with high temperature and low rainfall at the top right and to “Flooding Rains” with low temperature and high rainfall at the bottom left. Smoothed data points for anomalies of mean monthly daily maximum temperature and monthly rainfall totals generally lie close to the sloping blue line in such graphs for all of the last 20 years. (Search “3-year climate trends”, this one, for example).

Notice that record high and low values of smoothed anomalies of rainfall and daily maximum temperature (dates marked in blue) lie close the this blue line, supporting the estimate.
Empirically, one degree of increase in temperature anomaly matches 20 mm of decrease in monthly rainfall anomaly: the Mackellar Constant for Manilla is -20mm/month/degree.

* By arrangement with the Licensor, The Dorothea Mackellar Estate, c/- Curtis Brown (Aust) Pty Ltd.

July 2019 had the warmest days

Ruby Saltbush Enchylaena tomentosa

Drought-proof Ruby Saltbush

Only the middle week of July was not warmer than normal. Nearly all days and nights were above average for this coldest time of the year, but none was exceptional. No night minimum was as warm as ten degrees. There were 15 frosts (normally 17), but, as happened in July 2009 and 2010, there were no severe frosts reading below minus two degrees in the screen.
Rain was recorded on the 8th and 9th, estimated as 5.0 mm and 5.5 mm.

Weather log July 2019

Comparing July months

The last three July months saw maximum, mean, and minimum temperatures steadily rising, with the temperature range (17 deg) staying high. That was not true earlier in the decade: from 2008 to 2012 temperatures were steady and the daily temperature range (14 deg) was low, with cool days and warm nights. It was the case again in July 2015 and 2016, as shown here.
Indicators of moisture were again low, but not as low as in July 2018, with its record low dewpoint and cloudiness. The (estimated) rainfall total of 10.5 mm is at the 14th percentile for July.

Climate at July 2019

Drought

I have reported separately on the on-going drought that continues to break low-rainfall records at durations of 15-months and longer.


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.  Since no 9 am readings have been recorded since August 2018, 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 July 2019

Record dry and warm (as smoothed)

3-year climate trends to July 2019

July raw anomaly data (orange)

Temperatures

Daily maximum temperature anomaly (all x-axes): above the maximum for smoothed values.
Daily minimum temperature anomaly (lower left): just above the upper limit of normal values.
Subsoil temperature anomaly (lower right): very high.

Moistures (moist is at the bottom)

Rainfall anomaly (upper left): very low.
Cloudiness anomaly (upper right): normal.
Dew point anomaly (middle left): low, like the other recent values.
Daily temperature range anomaly (middle right): very high.

 Latest fully smoothed data (red), January 2019

Temperatures

Daily maximum temperature was a new record positive value of +1.79 deg, beating +1.62 deg set in March and December 2018.
Daily minimum temperature set a new record of +2.18 deg, beating +1.98 deg set the previous month.
Subsoil was normal due to phase lag.

Moistures (moist is at the bottom)

Rainfall smoothed anomaly was a new 136-year record value of minus 31.75 mm per month, breaking the record of minus 30.8 mm set the previous month.
Cloudiness was normal.
Dew point was low.
Daily temperature range was normal.


Notes:

January data points are marked by squares.

Smoothing Continue reading

June 2019 still warm and dry

Road in Manilla

The Bendemeer road

The second week was 3.2° warmer than normal, the third week cool, and the fourth warm again. There were 12 frosts (normally 13), with that on the 22nd reading minus 4.3° in the screen. It was one of only 20 readings below minus 4.0° this century.
The wettest of the four rain days registered only 2.3 mm.

Weather log June 2019

Comparing June months

The mean temperature for June has changed little in recent years. It has slowly fallen from 11.5° in 2013 to 10.8°. That is higher by 0.5° than the 10.3° that was normal in the first decade of this century. This month’s mean daily maximum (18.3°) and mean daily minimum (3.3°) were also just 0.5° above normal.
This June was a little more moist than last June in its higher dew point and narrower daily temperature range but less moist in cloudiness and rainfall. The low total rainfall of 4.8 mm (est.) is at the 8th percentile, the 12th driest June on record.
Climate for June 2019

Drought

The on-going unprecedented drought is reported in another post.


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.  Since no 9 am readings have been recorded since August 2018, 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.