Rainfall Shortage Jan 2000 – Mar 2019

Severe and extreme rainfall shortages Jan 2000 to Mar 2019

The current drought now has an extreme rainfall shortage of 84 months duration that must have commenced in 2012.

A new graph

This graph shows the onset, persistence, and breaking of episodes of extreme and severe rainfall shortage (droughts) at Manilla since 2000. It is a part of a graph of the complete historical record from 1884. In this case, the time axis is expanded to resolve individual months. The graph features and the data analysis are explained in the post “Rainfall Shortage History: Manilla”.

Extreme shortages, up to the 1st percentile, are shown in red and severe shortages, up to the 5th percentile, are shown in grey.
The dashed line labelled “Last Good Data” is a limitation to determining cumulative rainfall deficiency. Future observations may make any point to the right of this line more extreme.

The pattern of rainfall shortages

Shortages before 2018

In 2000 there were no rainfall shortages classed as “severe”. There had been hardly any since 1994.
The drought that occurred in winter 2002 had extreme rainfall shortages at all durations from 3 months to 12 months. Severe shortages extended even further: from 2 months to 30 months. However this was a much shorter drought than six others in the history of Manilla.

Although severe rainfall shortages (grey) occurred at intervals between 2002 and 2018, they formed small clusters, mainly at short durations. Years affected were 2005, 2008, 2009, 2012, 2013, 2014, and 2017. By 2014, there was public concern about shortage of rainfall. Although there were few seasonal severe shortages at that time, the graph shows that there were severe shortages at durations from 12 months to 30 months through 2013 and 2014.

With the benefit of current data, we can see that severe and even extreme shortages of duration longer than 60 months were, in fact, initiated in 2012 or earlier. They were not apparent at the time, however. In October 2016, in a post “Is There Any Drought Now?”, I argued that there was no evidence of drought at that time.

An alternative expression of rainfall status during this time is a graph of smoothed rainfall anomalies in the post “17 Years of “Droughts and Flooding Rains” at Manilla”.

Shortages at 2018

Shortages of rainfall became alarming in 2018. The winter months had extreme shortages of 2-month to 6-month duration. Earlier and later dry months contributed to a 15-month extreme shortage, such as had not occurred since 1966, half a century earlier.
After November 2018 none of the short-term rainfall totals for durations less than nine months has been even a severe shortage. In other respects, the drought has deepened. As recent monthly rainfall values have scarcely risen above normal, durations of severe or extreme shortage have become longer and longer. As at March 2019, extreme shortages prevail at 30 months, 72 months and 84 months. Severe shortages prevail at even longer durations, now up to 120 months (10 years).


Notes

The Millennium Drought absent
“Rainfall Shortages” or “Droughts”?
Short droughts are worst

The Millennium Drought absent

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2018 hottest and driest

In the nineteen years 2000 to 2018, this last year was the hottest and the driest.

Climate logs 19 years

Climate records kept at 3 Monash Street, Manilla from April 1999 yield these eight graphs of climate variables. The graphs on the left (red) show heat and those on the right (blue) show moisture.
These graphs show the figures for calendar years. They do not show hot summers or cold winters. In particular, each summer spans two calendar years.
In general, the temperatures in this 19-year record rose, with a pause between 2004 and 2012. Moisture peaked about 2010.

Day Temperatures

Daily max temp, 19 years

Day temperatures are shown by the mean maximum temperature in the thermometer screen. The year 2018, at 27.13°, had the hottest days by far. Four other years with hot days were widely spread: 2002, 2009, 2014, and 2017. The coldest days were in 2008 (24.57°) and 2010 (24.60°), followed by 2001 and 2011.

Average Temperatures

Daily Mean Temp, 19 years.

This graph shows warmth in general, as is done in the study of global warming. For each day, the daily maximum and daily minimum temperatures are averaged. Then these values are averaged for each year. The year 2018 was the warmest (19.11°), but 2017 was only fourth, beaten by 2014 and 2009. The coolest year in this century was 2008 (17.19°), followed by 2001, 2011, and 2012.

Night temperatures

Daily min temp, 19 years

Night temperatures are shown by the mean minimum temperature in the thermometer screen. The year 2018 , at 11.09°, had only the fourth warmest nights. The warmest were in 2014, at 11.34°, followed by 2010 and 2009. Years with nights cooler than 10° on average were 2012, 2008, 2006 and 2001.

Subsoil temperatures

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Manilla’s Hot Days to June 2015

Log of annual hot days in 16 years This post updates a similar one by including three more years to make a total of sixteen. It is in the same format as a recent post on Manilla’s frosts. Because the summer, which has the most hot days, crosses from one calendar year to the next, I have begun each year at July. I have called days warmer than 35° “hot days”, and days warmer than 40° “very hot days”.

Note added.

I have analysed the pattern of hot days in more detail in a later post “Hot days and ENSO”. By finding the relative frequency of hot days in all of the hotter months, I show that there is a cyclic variation related to ENSO. The cycle period is near 1.5 years, not 3 years as the log of annual frequency of hot days (above) suggests.

Graphical log of hot and very hot days

The first graph is a log of the number of hot and very hot days in each year. The three years with the most hot days had almost the same number: the year ’02-’03 had 41, the year ’09-’10 had 44, and the year ’13-’14 had 43. The two years with the fewest were ’07-’08 which had 5, and ’11-’12, which had only 4. The 13-year average is 26. Counting only the very hot days, ’03-’04 had the most (6), and four years had none at all. On the average, two days exceeded 40° in a year. (These are thirteen-year averages, not updated.) The number of hot days per year seems to have a cyclic pattern, with a period that increases from two years to four years during this short record. This is just a curiosity. The pattern of hot days has a lot in common with the pattern of smoothed monthly temperature anomalies for all months. These are plotted here, on a graph that relates them to ENSO. The relation of Manilla daily maximum temperature to ENSO was quite close from 1999 to 2011, but failed almost completely since mid-2011. In the earlier post on frosts, no cyclic pattern can be seen, nor any relation to ENSO.

New Record hottest days

In the sixteen years, there have now been 37 days hotter than 40 degrees: that is, 2.4 days per year. It remains true that December has fewer very hot days than November or February. A new record was set on 12/1/2013 by a daily maximum temperature of 43.2 degrees, beating the 42.6 degrees of 20/11/2009. This record was broken again on 3/1/2014, with 43.7 degrees. In the latest year, the hottest day (41.1 degrees) ranked only 12th, and it was not in summer, but in November.

Three new annual graphs

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Manilla’s Frosts to 2014

Graphical log of frosts

This post updates a similar one by including three more years to make a total of sixteen.

The Number of Frosts in Each Year

The first graph is a log of the number of frosts in each year. The pattern is different when counting all frosts or only severe frosts.
The log for all frosts had two periods of stable, medium numbers of frosts: from 1999 to 2003, and from 2008 to 2011. Three years had many frosts: 2004 (68), 2006 (70), and 2012 (69). The year 2007 had the fewest frosts (43) until beaten by 2013 (34).
In the logs for severe frosts below minus 2° or minus 4° in the thermometer screen, the drought year 2002 stands out as the most frosty by far. It had the coldest mornings: -5.1° on both the 2nd and 11th of July.

The Last Three Years

Monthly frosts in 2012, 2013, and 2014.

The second graph compares the mean seasonal pattern of frosts with the patterns for the three latest years: 2012, 2013, and 2014.
The frost season of 2012, which almost matched the record 70 frosts of 2006, began early and ended late. May had 13 frosts (like the 14 of 2006) and September had 10 (like the 8 of 2003).
The curve for the season of 2013 ( the new record fewest) was like that of a normal frost season, but lower.
The year 2014 was not very frosty, because the season began late, with no frosts in May and only nine in June.

Monthly frosts each year

Graphs showing the seasonal frost patterns for earlier years are copied here.

 

 

 

 

 

 


There is 2013 reserch on frost in NSW titled “Understanding frost risk in a variable and changing climate” reported here.
It is in GRDC Update Papers (Grains Research and development Corporation). The research is done by Steven Crimp and co-workers at CSIRO Climate Adaption Flagship.
Referring to the period 1960 to 2010,
“Over many parts of NSW the frost season length has broadened by as much as 40 days and the mean number of consecutive frost days has increased to 5 days.”

February Climate Anomalies Log

Heat indicators log for February

This post is the twelfth in a set for the 12 calendar months that began with March. Graphs are sixteen-year logs of the monthly mean anomaly values of nine climate variables for Manilla, NSW, with fitted trend lines. I have explained the method in notes at the foot of the page.

Raw anomaly values for February

Extreme values of February anomalies were as follows:

Daily Maximum Temperature Anomalies (3) -4.2 deg: February 2008; -3.3 deg: February 2012; -3.3 deg: February 2013;
Daily Mean Temperature Anomalies (1) -3.3 deg: February 2008;
Rainfall Anomalies (1) +120 mm: February 2012;
Dew Point Anomalies (2) -4.6 deg: February 2014; -4.6 deg: February 2015.

Trend lines for February

Heat Indicators

All heat indicator quartic trends began slightly low and ended slightly low. They had a low peak about 2004, and a trough later. The trough was deepest and earliest for daily maximum temperature (2011), followed by daily mean temperature in 2012, daily minimum temperature in 2014, and subsoil temperature in 2015 or later.

Moisture indicators log for February

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January Climate Anomalies Log

Heat indicators log for January

This post is the eleventh in a set for the 12 calendar months that began with March. Graphs are sixteen-year logs of the monthly mean anomaly values of nine climate variables for Manilla, NSW, with fitted trend lines. I have explained the method in notes at the foot of the page.

Raw anomaly values for January

Extreme values of January anomalies were as follows:

Daily Maximum Temperature Anomalies (1) -3.7 deg: January 2012;
Rainfall Anomalies (5) -70 mm: January 2002; -75 mm: January 2003; +80 mm: January 2004; +94 mm: January 2006; -85 mm: January 2014;
Dew Point Anomalies (2) +3.1 deg: January 2006; -7.4 deg: January 2014.

Trend lines for January

Heat Indicators

All heat indicator quartic trends began low and ended slightly high, and had a low peak in 2003, -05, or -06, and a shallow trough about 2012.

Moisture indicators log for January

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December Climate Anomalies Log

Heat indicators log for December

This post is the tenth in a set for the 12 calendar months that began with March. Graphs are sixteen-year logs of the monthly mean anomaly values of nine climate variables for Manilla, NSW, with fitted trend lines. I have explained the method in notes at the foot of the page.

Raw anomaly values for December

Extreme values of December anomalies were as follows:

Daily Maximum Temperature Anomalies (2) -3.6 deg:
December 2010; -4.7 deg: December 2011;
Rainfall Anomalies (1) +80 mm: December 2004;
Minus (Temperature Range Anomaly) (1) +3.7 deg: December
2010;
Dew Point Anomalies (1) -4.4 deg: December 2013.

Trend lines for December

Heat Indicators

All heat indicator quartic trends began low and ended high, and had a peak in 2003 or 2004 and a trough in 2010. The range from peak to trough was greatest for maximum anomalies and least for minimum and subsoil anomalies.

Moisture indicators log for December

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