Tag Archives: climate

Autumn 2008 was dry and cool

Posted in Manilla NSW, Season Weather by

Weather log autumn 2008

The daily weather log

Temperatures were about normal in mid-March and again during parts of May. Otherwise they were low. The daily temperature range was generally higher than usual, but was less on rainy days.
There were nine mild frosts, which is near the average.
Humidity was very low in early April and early May.
There were 13 rain days, which is normal. They were mainly in late April and mid-May, for a very low total of 37 mm. April the 24th was the wettest day, with 12.8 mm.
Cloud varied a lot from day to day. Clear skies were common in March.

Comparing autumn seasons

This autumn was very cool: mean daily mean temperature and minimum temperature are the lowest in the ten year record. Mean daily maximum temperature was lower in 2003, which is one of three autumns sharing the next coolest mean temperature.
This autumn’s very cool nights (8.2°) caused the largest daily temperature range on the graph (16.9°), similar to the 16.8° of 2005. Both came with very low rainfall,
Autumn humidity seems to have decreased through the decade, with this autumn’s Dew Point of 6.4° the lowest.
This graph includes some very dry autumns. Autumn 2005 was the 7th driest on record, in the 6th percentile for autumn rainfall. This autumn was similar, in the 7th percentile. Autumn 2002 was in the 18th percentile, as that year’s drought had not fully developed. By contrast, autumn 2003 and 2007 were wet, in the 72nd and 75th percentiles.
(Contrary to the forecast, this autumn was dry. It was one of twelve autumns on record that had less than one fifth of the preceding summer’s rainfall. Three of the twelve were 2005, 2006, and 2008. This is amazing: something that usually happens one year in ten happened three years in four! Another three of the twelve were 1971, 1973, and 1976. At that time it was three years in six.)
At 26% cloudy mornings, this autumn was normal.

Climate autumn 2008

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew Point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperatures, including subsoil at 750 mm, and other data are from 3 Monash Street, Manilla.

Perfect May weather in 2008

Posted in Manilla NSW, Monthly weather by

The daily weather log

Weather log May 2008

The mean daily temperature rose to a normal value by the middle of the month and then tracked down along the usual curve. Daily maxima were near normal except for one cool Sunday. Daily minima were also normal, except for a warm night (12°) on the 16th and six mild frosts.
The second week had very dry air, but the third week was humid, with four days of rain showers totalling 14 mm. A  number of cloudy days produced no rain.

 Comparing May months

Climate May 2008

The weather for May was normal in all respects: maximum, mean, and minimum temperatures, humidity, cloudiness, and rain. Some of us would call it perfect weather!
Normal temperatures break a five-month spell of unusually cool weather. On the other hand, as the graph shows, this month is much cooler than May last year. Six frosts is the normal number for May, and compares with 3 last year and 14 the year before.
Humidity, indicated by early morning Dew Point, is similar to that in 2004 and 2005. It had been higher early in the decade, due to moisture from “La Niña”.
At 14 mm, this May’s rainfall is not very low. Being well below the May average (40 mm) does not mean much. In Manilla, rainfalls in the months of March, April and May are highly “skewed” so that the very lowest rainfalls are the most common. Rainfalls of 5 mm or less occur often – more often than one May month in eight (There are two on the graph!). Fourteen millimetres is in the 25th percentile of May rainfalls.
The rainfall total for this April and May together (34 mm) is in the 9th percentile of two-monthly totals (a serious shortage) and the three-monthly total (36 mm) is in the 2nd percentile (a severe (almost extreme) shortage). The four-month total is better (in the 28th percentile) and the five-month total better still (in the 35th percentile). The six-month total (summer plus autumn) is high: in the 61st percentile. Beyond that, the totals for 9, 12 and more months are all normal, that is, near the median.

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperature and other data are from 3 Monash Street, Manilla.

 

April 2008: fog and black frosts

Posted in Manilla NSW, Monthly weather by

The daily weather log

Weather log April 2008

Usually, the air cools and dries out quickly during April. This time only the daily maximum temperature came steadily down. The average temperature hovered near 16° until the last days.
At first, the air was very dry, with a Dew Point below 5°. Under a clear sky on the 4th the early morning temperature went down to 2.1° in the screen, which would be 0.1° of frost. Because the Dew Point (-3.8°) was much lower than that, there was no ice on the grass, which made it a “black frost”. It is said that frosts seldom occur in Manilla before ANZAC Day (April 25th).
As the month went on the air got moister. By the 24th the clouds in the overcast sky were down on the hills. On the 26th the town was blanketed in fog as the humidity hit 100%. (Temperature and Dew Point were both 8°.)
Evaporation was increased by strong winds on the 27th and 28th.
Dry southerly air made the last three days cool and sunny. Black frosts came back giving screen temperatures of 0.6° and 0.1° (around 2° of frost).
Practically no rain (3.6 mm) fell in more than seven weeks from 29 February to 21 April. After that, there were four rain days, including 12.8 mm on the 24th. In total, 20.2 mm fell in April, on five rain days.

 Comparing April months

Climate April 2008

The mean temperature this month was nearly as low as the coolest  April in ten years (1999). This was the fifth cool month in a row: December (1.0° down)  January (1.9° down) February (3.1° down) March (0.9° down) and April (2.1° down). As a 5-month average the temperature was 1.8° below normal. It is as if Manilla had been moved 400 km south (near Grenfell) or 150 metres higher (like Barraba). (Note added: This was a time of global low temperature.)

The month was as cloudy as usual, but less humid.
At 20 mm, this April’s total rainfall is about 20 mm below average, as in 2001 and 2004. It is much higher than in April 2005, when Manilla was in a rainfall  drought for several months.
The rainfall total for this March and April (22 mm) is in the 4th percentile of two-monthly totals: a severe shortage. However, the three-month total (138 mm) is just below the median, and the totals for 4, 5, 6, 9 and 12 months are all at the median or above it. In particular, the 6-month total (401 mm) is quite high, at the 75th percentile.

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperature and other data are from 3 Monash Street, Manilla.

 

Dry, Dry March 2008

Posted in Manilla NSW, Monthly weather by

The daily weather log

Weather log March 2008

After 115.6 mm of rain in February, March crashed to just 2.2 mm with only three rain days. In 1971 it was worse: that year February had 173 mm and March 1 mm!
This month the air was very dry, too. Morning Dew Points which had been quite low (10°) all month, plunged to zero or less in the last days.
Although there were six cloudy mornings, eighteen mornings were completely cloud-free. The whole of the summer had only thirteen free of cloud!
Due to the dry, fine weather, three-quarters of the days had a range of temperature higher than the normal value of 15.4°. Three days had a range of 21° or more.
The 7-day average temperature began and ended well below normal, but was above normal in the third week. Nights were cold (8° below normal) in the first and last days.

 Comparing March months

Climate March 2008

The mean daily maximum temperature this March (29.9°) is normal, but the mean daily minimum (12.2°) is the lowest in ten years. It is 2° below the average, and 4° below that of 2007 (and 2000).
The mean morning Dew Point, 8.8°, is 3° lower than normal for March. This shows very dry air, which is wilting many shallow-rooted plants.
The total rainfall of 2.2 mm is much lower than the other Marches on the graph. It is not very low compared with Marches in the long-term record: it is on the 6th percentile. In Manilla, rainfall varies more in March and April than in other months.
There must be a lot of water deep in the soil. Total rainfalls for the last 2, 3… 18 months are all above the median. The four and five-month totals are particularly high, in the 83rd percentile.

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperature and other data are from 3 Monash Street, Manilla.

 

Summer 2007-08 was very cool,cloudy and wet

Posted in Manilla NSW, Season Weather by

Weather log summer 2007-08

The daily weather log

Most summers recently have had one or two days over 40° and nights over 25°. Not this summer! The hottest day reached only 36.3°, and the warmest night 22.1°. Only 37 days went over 30°: half the usual number. Air conditioners may not have had much use!
The 7-day temperature curves show warm spells in the second week of December, and in the second and fourth weeks of January. Temperatures were then normal. The rest of the time they were well below normal.
Daily minimum temperatures were not so low. This made the daily temperature range small, especially during humid spells.
Humid weather (dew point 16°) came with rain in early December, mid-January, and early February. The air was rather dry (dew point 10°) at New Year and in the very last days of summer.
There were 33 rain days (normally 21). The longest dry spells were eight days from the 22nd of January, and nine days from the 20th of February. February the 6th was the wettest day, with 32 mm, and the summer total was high, at 311 mm.
It was a very cloudy summer. More than half the mornings were cloudy (over 4 octas) and many (18) were completely overcast. Only 13 mornings had a sky clear of cloud.

Comparing summer seasons

Mean daily maximum temperature and mean temperature this summer were the lowest in the nine year record. Mean daily minimum temperature was lower in 1999-2000, which has the next coolest mean temperature. While the cool summer of 1999-2000 had a large daily temperature range (15.6°) related to low rainfall, this summer had a very small daily temperature range (13.2°) related to high rainfall and cloud.
The mean daily maximum this summer (29.7°) is 3.3° below the nine-year average. The fall of over 4° from the very high maxima of the last two summers is dramatic.
Humidity was normal for the time of year.
For rainfall, this short record begins with the 15th driest summer (99-00, 125 mm) and includes the 19th wettest summer (05-06, 319 mm). This summer’s rainfall of 311 mm is 84 mm above the long-term summer average of 227 mm. It is on the 83rd percentile.
At 53% cloudy mornings, this summer season is by far the cloudiest of any season in the nine-year record. No others exceeded 41%.

Climate for summer 2007-08

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew Point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperatures, including subsoil at 750 mm, and other data are from 3 Monash Street, Manilla.