3-year trends to July 2011.

Parametric plots of smoothed climate variables at Manilla

“Dry air and little rain”Trends to July 2011.

These graphs have data points for the last 36 months. In that time, the climate at Manilla, NSW has experienced a cycle from near-normal (Aug-08), through very warm and dry (Nov-09), then very cool and wet (Oct-10) , and back to near normal (Jul-11). For most variables, the raw anomaly values of July 2011 are near the smoothed anomaly values for August 2008.

Three variables have not returned to normal. Rainfall and Dew Point are far below normal, as typical in drought, and Subsoil temperature is high.
Cloudiness is “normal” in the new cloudy regimen in place since September 2007.

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.

3-year trends to June 2011.

Parametric plots of smoothed climate variables at Manilla

“Dry air but not warm or sunny”Trends to June 2011.

Raw anomaly data for June 2011 (shown in orange) are a little strange.
Daily max temperature, shown on the x-axis of all six graphs, has stalled without quite rising to normal from the extreme cold of last October.
Two variables indicate severe drought: Rainfall was very low, and so was the early morning Dew Point.
Most other variables are near normal, or slightly to the “flooding rains” side of normal.
Percent of cloudy mornings (>4 Octas) remains stable at a very high positive anomaly. For a calendar month that had 35% cloudy mornings in the reference decade beginning in 1999, it now has 55% cloudy mornings.

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.

Autumn 2011 Normal but Cloudy

 

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

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.

3-year trends to April 2011.

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.