Tag Archives: dry air

Winter 2012: very dry air

Posted in Manilla NSW, Season Weather by

Weather log winter 2012

There were two spells of cloudy very wet weather with warm nights, one in the first week of June and one in the second week of July. By contrast, the first week of August was sunny, but with cool days and very cold nights.

Early valley fogs were common in June and July. The total number of frosts (45) was normal, as was the number of severe frosts below minus two degrees (8).
Like last winter, this winter had normal air temperature. Unlike last winter, rainfall was not low, nor the skies extremely cloudy.
Humidity, however, was even lower, marked by a mean early-morning Dew Point of 0.7° (2.2° lower than normal), a new winter record for dry air.
Subsoil temperature was a new winter record high value: 17.1°.
There were 16 rain days, which is just below normal. The winter total of 148.2 mm is in the 66th percentile.Climate winter 2012

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.

Very dry air in May 2012

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log May 2012.

Most days were fine, and only two or three were cool and overcast. There were 13 frosts, twice the usual number, but May 2006 had 14. Rain totalling 13.8 mm fell on five rain days, with a maximum reading of 6.2 mm on the 25th.

 Comparing May monthsClimate May 2012.

This was a very dry month, marked by dew points four degrees below normal, but it was not as dry as May 2006, as is clear from the graph.
The rainfall total is well below the May average of 40.3 mm: it is in the 24th percentile (3/4 of May months have been wetter). In extreme contrast, the nine-month rainfall total of 852 mm is extra-ordinarily high. Only 13 nine-month totals have been higher, and then only in the four years 1890, 1928, 1956 and 2012 (April). The record for a nine-month rainfall total was 1030 mm, set in June 1956.

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.

 

3-year trends to January 2012.

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla

“Low Dew Points and cold days persist”Trends to January 2012.

Except for humid November 2011, Dew Points at Manilla (Centre left graph) have now shown remarkable aridity for nine months. The July 2011 value for Dew Point anomaly, now fully smoothed, requires the blue line to be moved yet again. It sets a new lower limit for smoothed Dew Point anomaly: minus 1.70 degrees.
Daily maximum temperature (X-axis, all graphs), from a remarkably low value (-4.7) in December, rose only to -3.6 in January.
On the top left graph, the rainfall anomaly returned from a record positive value in November to stongly negative within two months.
Cloudiness went from very high to extreme.
Daily temperature range (centre right graph) and daily minimum temperature (bottom left graph) moved back from the extreme values of December.

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.

September 2011: Dry Air with Rain

Posted in Manilla NSW, Monthly weather by

Humidity this month was extremely low. Early morning Dew Point readings averaged 1.7°, which is 3.7° below normal for September (5.4°). Relative humidity at sunrise was about 70% instead of 80%, and in the heat of the day 25% instead of 35%. This is the sixth month in a row with very low humidity, beginning with April, which had Dew Points 1.5° below normal.
In thirteen years only three months have had Dew Points further below normal. They were: July 2002 (down 3.8°), October 2002 (down 3.9°), and May 2006 (down 3.9°).
Plants are stressed by such dry air, and litter will burn easily.

The daily weather logWeather log September 2011.

Most September days were warm and sunny, but heavy rain registered on the 9th (38 mm) and on the 29th (40 mm) brought cold windy overcast weather. The 9th, at 12.9°, was the coldest September day on this record. There had been no days colder than 14°.
While many days had no cloud at all, seven days (marked “H”) had a thick smoke haze from Queensland.

 Comparing September monthsClimate September 2011.

Mean temperature readings were below normal by half a degree or more. The extremely low mean early morning Dew Point (1.7°) contrasts with the very high value last September: 7.3°
Twenty-seven percent cloudy mornings is a normal value, but lower than in the last three Septembers.
The rainfall of 91.4 mm is extremely high, in the 94th percentile for September (Average: 41.1 mm.). Rainfall totals for groups of months are all near normal. The nearest to a “drought” is the 6-month total (221 mm) which is in the 21st percentile; the nearest to a “deluge: is the 12-month total (724 mm) which is in the 68th 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.

Winter 2011 extremely dry

Posted in Manilla NSW, Season Weather by

Weather log winter 2011For temperature, this winter was normal. Otherwise, it was strange: it had the extreme low rainfall and low humidity that come with drought, without sunny skies or severe winter frosts.
During the season, two spells of weather stood out. In mid-June cool days and very warm nights came with rain, cloud, and high humidity. The last days of July and the first week of August had very warm sunny days with very low humidity. A mid-winter spell of cold weather in mid-July was not much colder than that in early June.
The number of frosts (40) was below the average number (44). The coldest screen reading was -3.7°, exactly on the average.
The percentage of mornings with more than 4/8 cloud (50%) was a new record for winter. Winters in 2008, 2009, and 2010 had percentages in the high forties, compared with the earlier average of 34%. On four mornings fog did not clear until late; five others had some fog in the valley.
Humidity was extremely low, marked by a mean early-morning Dew Point of 1.2°, the lowest winter mean on this record.
There were 19 rain days, which is normal. However, falls were extremely light: the highest daily reading of 8.2 mm was by far the lowest maximum reading in 13 winters. The winter total of 55.0 mm is in the 11th percentile: it was the 14th driest winter on record, only slightly wetter than that in the extreme drought year 2002 (44.6 mm).Climate winter 2011

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.