Tag Archives: 2011

June 2011 rather cool and dry

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log June 2011.

June began and ended with warm sunny days. The second week was cold: the 9th had a maximum of only 12° after a frosty night of -2.7°. Days from the 12th to the 15th were not much warmer, made miserable by overcast and rain, but the nights were warm. The 8/8 cloud recorded on the morning of the 24th was fog, which cleared to a blue sky at 10:45.
The highest rainfall reading was only 8 mm, recorded on the 22nd. Five rain days totalled 17.8 mm.

 Comparing June monthsClimate June 2011.

Of the mean temperature readings, only the mean daily maximum was a bit lower than usual. Days were not as cold as in June 2007. This time, there were 14 frosts, which is near the decade average.
The rainfall of 17.8 mm is rather low: on the 20th percentile for June. (The long-term June average is 44.3 mm.) June rainfalls have fallen rather steadily since June 2005, the sixth wettest on record at 109 mm. Nearly all rainfall totals for groups of months (up to 360 months) continue to be near normal. Only those for three months and four months are below the 25th 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.

 

Autumn 2011 Normal but Cloudy

Posted in Manilla NSW, Season Weather by

 

Weather log autumn 2011Normal autumn weather was broken by an almost rainless period from mid-April to late May. Temperatures fell very low, particularly at night. The minimum of minus 2.8 degrees on 15/5/11 was a record for autumn. The coldest nights were exceptionally dry: 17/5/11 had the lowest Dew Point in thirteen years, -9.3°. Even during the extreme drought of July 2002, with four Dew Point readings below -6°, the air did not get nearly so dry.

On the average (as shown below) temperatures and the Dew Point were near normal, except that days were rather cool, as in autumn 2008. On average, that autumn, however, was much drier, with cold nights. Autumn 2007 had been very warm and wet.
This time, the percentage of mornings with more than 4/8 cloud was 43%. That almost matches last autumn’s 45% and is far above those of autumns in the previous decade, which averaged just 25%.
Rain fell on 21 days, an unusually large number. The total rainfall of 116.8 mm is on the 52nd percentile for autumn. It is 16 mm below the autumn average (133 mm).Climate autumn 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.

3-year trends to May 2011

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla

“Flooding rains climate peaked here in October 2010”Trends to May 2011.

Smoothed data for spring 2010

Fully smoothed data points for spring (SON) of 2010 are plotted in red on the left edge of the graphs. They show that several variables reached peak values during the season. First, temperature range anomaly reached a minimum in September. Next, in October, daily maximum temperature anomaly reached a minimum, rainfall anomaly a maximum, and Dew Point anomaly a maximum. In November, subsoil temperature anomaly reached a minimum. Cloudiness anomaly may have reached a maximum in that month, but perhaps smoothed December or January values will be higher. Daily minimum temperature anomaly did not peak. Through spring it fell steadily from a high positive value.
In a “weatherzone” post, I noted a tendency for variables to peak in a particular order.
“For a “flooding-rains” peak:

  • First: Daily Temperature Range (min);
  • One month later: Rainfall (max), Cloud (max);
  • Two months later: Daily Maximum Temperature (min), Dew Point (max);
  • Four months later: Daily Minimum Temperature (min), Subsoil Temperature (min).”

Not much is different in this case. In particular, daily temperature range was the first to peak (WHY?), and subsoil among the last. However, the time of rainfall maximum did not precede the time when daily maximum temperature reached a minimum.

Data after November 2010

During summer (DJF) most variables seemed to be moving towards “droughts” but this pattern broke down in autumn:

  • Maximum temperature anomaly did not quite reach normal before falling again;
  • Rainfall anomaly became negative then returned to positive;
  • Cloud anomaly had just one negative value before returning to record cloudiness;
  • Dew Point anomalies accelerated to extremely low values;
  • Temperature range anomaly went very positive before falling slightly;
  • Minimum temperature anomaly fell rapidly, independent of maximum temperature anomaly;
  • Subsoil temp anomaly stabilised at a slightly positive value.

I am surprised that extreme cloudiness and extreme low humidity occur together. I am also puzzled about the weak association between daily maximum and minimum temperatures. This is a worry because daily minimum temperatures provide the most consistent signal of climate change during the last century.

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.

May 2011 cloudy, rainy, but not humid

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log May 2011.

May had five rain days (usually only three) but they came very late. The highest rainfall reading, 19.6 mm on the 23rd, ended a 35-day dry spell. Before the rain, the air had become extremely dry. The morning Dew Point on the 17th was -9.3° and the daily minimum temperature on the 15th -2.8°: both were 13-year record low values for May. The daily temperature range reached 24.9° on the 18th.
With the rain came cloudy, cold days. The 30th, with a maximum of only 11.1°, was the coldest May day in this record. It was nearly two degrees below the previous coldest: 12.9° on 29/5/00.

 Comparing May monthsClimate May 2011.

Mean temperatures were a little below average. There were 11 frosts, compared with the usual six.
After sunny April, May was back to the extreme cloudiness of the last three years. The air was not humid at all, however. The mean Dew Point was only slightly higher than in the droughty May of 2006.
The rainfall of 43.2 mm is on the 64th percentile for May, and just above the long-term May average (39.3 mm). May rainfalls have been low (or very low) for a number of years: this was the wettest May since 1998 (74 mm). Rainfall totals for groups of months (up to 360 months) continue to be near normal.

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 April 2011.

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla

“Sunny return from “flooding rains””Trends to April 2011

Most of the April 2011 raw data values (in orange), other than daily maximum temperature, are now on the “droughts” side of normal rather than the “flooding rains” side, which had dominated for about a year.

Smoothed October values include new 12-year record anomalies for daily maximum temperature (low) and cloudy days (high).

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.