Tag Archives: 2010

Winter 2010 wet, with few frosts

Posted in Manilla NSW, Season Weather by

 An episode of maritime climate

I have posted this seasonal report for winter 2010 on the front page, as a sticky post, to show how the climate of that season was not normal. It was not the average temperature or the rainfall that were unusual. The sky was very cloudy, the humidity very high, and the daily temperature range very low. The climate was equable, as one would expect at a place near the sea: a maritime climate. More in the footnote*

Weather log winter 2010

Temperatures this winter changed little from month to month. June, July and August each had temperatures near the season averages: maximum 17.0°, mean 10.7° and minimum 4.5°. Warm days were rare: only 11 exceeded 20° (usually 25). This winter was even less frosty than the last, with only 32 frosts (usually 44). The lowest minimum was -3.1°.
There were 33 rain days, about twice the usual number.

In terms of daily mean temperature, this winter was normal, However, cool days and warm nights made the daily temperature range (12.5°) narrower than in any winter in the 12-year record. It was also the cloudiest, at 49% cloudy mornings. Manilla’s climate became much more cloudy three years ago, when the average number of cloudy mornings in a month jumped suddenly from nine to twelve (See also these other graphs.). Humidity, as shown by early morning Dew Point was also very high this winter. All these changes reflect a more maritime climate, as on the coast.
Each month would have had rainfall close to average, were it not for one reading of 34.2 mm at the end of July. The total of 160 mm is in the 70th percentile, like that of the wet winters of 2005 and 2007.

Climate winter 2010

*Footnote. The nature of this episode is clear on the 3-year graphs of climate trends, such as that for August 2011. The top left graph shows that, in June, July, and August 2010, rainfall was a little high and daily maximum temperature rather low. The bottom left graph shows the main anomaly: daily minimum temperature remained extremely high while daily maximum rapidly fell, reaching a record low value by October 2010. From July to November that year the difference between daily maximum and daily minimum temperature was some three degrees less than normal.
The middle graph on the right shows directly that the daily temperature range in those months was at record low (narrow) values.

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.

Cool days in August 2010

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log August 2010 Manilla

August had no extremes. Only four days exceeded 20° (usually thirteen days), and only ten nights were frosty (usually fifteen). The subsoil temperature failed to rise during the month, ending at 13.5°, which is 1.0° cooler than normal.

Rain fell on 13 days, an August record for the decade, but the highest reading was only 10 mm.

Comparing August monthsClimate August 2010 Manilla

The mean daily maximum temperature (26.5°) was the lowest for November on this 12-year record. The mean daily temperature range (12.4°) was (with November 2008) a record low value.

Mean subsoil temperature (20.4°) was the lowest since November 1999. The month ended with subsoil temperature (then 22.2°) trailing only 10 days later than its usual date. It had begun the month 22 days late.
There were more cloudy mornings (53%) than in any November on this record.
The rainfall of 105.4 mm is in the 84th percentile for November, far above the long-term average of 67 mm. Totals for groups of months up to 15 months are now all above the median, as is the thirty-year total.

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.

July 2010 Rain Twice Average

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log July 2010 Manilla

July began cold. The 2nd, with a maximum temperature of 9.1°, was the coldest July day in the record from 1999. The only two colder days were: 8/06/07 (8.8°), and 20/06/07 (8.3°).

Two warm spells followed, marked mainly by nights that were very warm for mid-winter. The minimum on the 12th (11.8°) was 10° above normal, and that on the 31st (13.5°) was 11.3° above normal. Colder nights included twelve mild frosts, the fewest on record.
There were 13 rain days spread through the month. The reading of 17.2 mm on the 29th was topped by 34.2 mm on the 31st.

“Normal Temperature”

Each Manilla monthly weather graph has dashed curves to show the temperatures that are normal for each day of the year. They are harmonic curves matching 10-year averages from March 1999. On this July graph, the lowest values are marked with a double “X”. Winter cold is due to lack of heat from the sun, which yields least heat on the 21st of June (the winter solstice). On that day the sun is lowest and shines the shortest time. However, it takes many days for the air to cool down. On average, the coldest day in Manilla comes 17 days later (July 8th) and the coldest night 22 days later (July 13th). Manilla’s coldest day and night follow the solstice with an unusually short lag time. (See Wikipedia: “Seasonal lag”.)

See the monthly weather report for January 2010 for the highest normal temperatures of the year. These relationships are shown on a graph here.

Comparing July monthsClimate July 2010 Manilla

Due to cloudy nights, the mean daily minimum temperature (4.6°) was by far the highest in the 12-year record for July, and 2.4° above the average. Because the mean maximum temperature was normal (16.9°), the mean average temperature was also high (10.8°). The mean daily temperature range (12.3°) was the narrowest in the July record.

Very high humidity was shown by a mean early morning Dew Point of 4.6°, higher than any since July 1999 (5.7°). The percentage of cloudy mornings (61%) was the highest, not only for July months, but for any month in this record. Nineteen mornings were completely overcast.
The rainfall of 79.8 mm is in the 90th percentile for July: only 12 July months have been wetter. It is close to double the long-term average of 41 mm. As a result, total rainfalls for the last two months and three months are now above the median. No serious rainfall shortages remain. The worst shortages are far from serious: the 15-month and the 9-year totals are both in the 14th percentile.

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.

June 2010 Weather on Average

Posted in Manilla NSW, Monthly weather by

The daily weather log

Weather log June 2010

Twice the weather cycled from warm, through rain, to sunny and cold. There were 10 frosty mornings, ending with a minimum down to -3.1°. While frostier than last June, which had only 5 frosts, it was less frosty than June 2006 (21 frosts) or June 2000, which had five mornings below -4°.
A modest rainfall reading of 21.8 mm on the 3rd was the highest since December and the third highest in 12 months. Seven rain days brought 42.8 mm for the month.

 Comparing June months

Climate June 2010

All mean temperatures, Dew Point, and cloud were close to their averages. The daily maximum temperature was 0.6° down, and the daily minimum temperature 1.1° up, making the daily temperature range (13.2°) narrower than normal by 1.7°.
The rainfall of 42.8 mm is in the 57th percentile for June. It is close to the long-term average of 44 mm. In 14 months since April 2009 no month has beaten its average. All the same, groups of months show no serious rainfall shortages. Even the 15-month total (573 mm) has now risen to the 10th percentile.

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.

 

Extremely Cloudy Autumn 2010

Posted in Manilla NSW, Season Weather by

Weather log autumn 2010

There were dry spells in mid-March, mid-April and early May. Each had very low humidity and mainly sunny weather. The first two had very warm days, but the third had cold nights. The final week brought one third of the season’s rain, with overcast skies, very high humidity, and very warm nights.
In all, there were 16 rain days, totalling 82.0 mm. No rain day exceeded 10 mm.
The subsoil temperature (750 mm depth) fell as is normal for autumn in Manilla, pausing for a few days after each peak in air temperature. By the end of the season, the subsoil was as warm as the air during the heat of the day.

This year, each of the months March, April and May was the cloudiest in the 11 year record. As a result, this autumn (45%) was also the cloudiest. Of 92 mornings, 41 were cloudy (>4/8 cloud): nearly twice the usual number of 23. The previous highest (last year) had only 30 cloudy mornings.
Due to the cloud, the daily temperature range (14.9°) was a degree narrower than usual. As the mean temperature was rather high, the result was a daily minimum temperature a degree above normal. Other temperatures, and the Dew Point, were near normal.
The total rainfall of 82 mm is again on the 30th percentile for autumn. It is 31 mm below the autumn median rainfall (113 mm).

Climate autumn 2010

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.