Tag Archives: 2013

Autumn 2013 began wet

Posted in Manilla NSW, Season Weather by

Weather log Autumn 2013Three quarters of the rain this autumn fell in the first two days: 31 mm and 45.4 mm. After that, the heaviest falls were 6.2 and 6.8 mm late in May. Days were cool with the rain, and warm in late March and late April. The warm days in late March came with warm nights, but the warm days in late April brought very wide daily temperature ranges instead.

This autumn was like autumn last year. That is, it was near average in most respects, but with high subsoil temperature and plenty of cloud. Dew points were even lower, reaching a record low value of 6.1°.
Rain fell on 11 days (normal), totalling 103 mm. This is below the 125-year autumn average of 133 mm, and in the 46th percentile.Climate autumn 2013

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 2013

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla

“Still warm; not quite so dry”Trends to May 2013.

May continued warm, but not quite so dry. Skies became cloudy again, and minimum temperature rose back to normal.

Points in red for November 2012 complete fully-smoothed data for spring 2012. They define a reversal of climate. Anomalies of moisture variables (rainfall, cloud, dew point, and (minus) temperature range) peaked in the “drought” sense in September or October. The anomaly of daily maximum temperature peaked (probably) in November, and that of daily minimum temperature peaked later (date uncertain).

The curved red arrows on the first graph emphasise the fact that, for these peaks and troughs, temperature extremes came a month or more after rainfall extremes.

ENSO and this 3-year temperature-rainfall-humidity record

I discussed the match between Manilla climate variation at this time and the El Niño – Southern Oscillation in a post on the weatherzone forum thread “ENSO Discussion 2013”: Post #1195723 of 26 May 2013.

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.

Another dry May in 2013

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log May 2013

Most days were warm and sunny, but there were cold, cloudy days from the 14th to the 24th, and three of them had a little rain. By the end of the month, there had been only 26.6 mm of rain in 90 days.
There were five frosty mornings, which is normal.

 Comparing May monthsClimate May 2013.

The mean maximum temperature was half a degree high and the mean minimum half a degree low. The mean early morning dew point (2.6°) showed low humidity, but it was not as low as the May record of 0.8° set last year. There were far more cloudy mornings (42%) than usual (24%), but fewer than in 2010 or 2011 (48%). The subsoil was 2.4° warmer than normal: its autumn cooling remained three weeks late.

The rainfall total of 13.6 mm was far below the average of 40.3 mm, but May has less rain than that in 23% of the years. Furthermore, Manilla’s May rainfall has been low for many years: in this century, only May 2011 (43.2 mm) beat the long-term average.
The two month total of 18 mm is now a severe shortage: in the 3rd 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.

 

3-year trends to April 2013

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla

“Back to warm and very dry”Trends to April 2013.

In April the raw value of maximum temperature anomaly became high and (indicating aridity) those of rainfall, dew point, and minimum temperature extremely low, and that of temperature range extremely wide. Cloud remained normal, and subsoil temperature high.

Fully-smoothed data points (red) for October 2012 continued to move towards higher maximum temperature, but scarcely moved further towards drought.

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.

April 2013: Very Dry Air

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log April 2013.

For most of the month, days were sunny and fairly warm, while nights were cool (but not frosty). The last days were several degrees warmer than normal: as warm as the first days. Two afternoons had extremely dry air, with relative humidity below 10%. While two days had a little rain, the month ended with no readings above 5 mm in eight weeks.

 Comparing April monthsClimate April 2013

 

The mean maximum temperature was a little high and the mean minimum rather low, making the daily temperature range (18.3°) an April record. The mean early morning dew point (4.3°) was also a record (low) value, but cloudiness was normal. The subsoil was almost 2° warmer than normal: its autumn cooling was about three weeks late.
The rainfall total of 4.8 mm was far below the average of 39.3 mm, but April has less rain than that in 15% of the years.

Five Recent Months had Very Dry Air

I have put headlines about very dry air on five monthly weather reports in the last twelve. It is true: the air has been much drier than it was from 1999 to 2009.
I judge the moisture in the air mainly by the dew point – the temperature when dew would form. Normally the early morning dew point, as a monthly average, changes through the year from 15 degrees in February to 2 degrees in July. In some recent months it has been far lower than what is normal for the month:

  • May 2012: 4.4° below normal;
  • August 2012: 4.4° below normal;
  • September 2012: 4.6° below normal;
  • October 2012: 6.6°(!) below normal;
  • April 2013: 4.7° below normal.

Even in the 2002 drought, the furthest the dew point went below normal was 3.9°, in October.
One degree of change in dew point is like 5% change in relative humidity. In these months the morning relative humidity has been below normal by 20% to 35%. Afternoon humidity has been down by more: many days have gone below 10% humidity. These extremely low humidity values must affect crops and pastures, pests and diseases, and may affect health.

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.