Tag Archives: april

Warm humid nights in April 2014

Posted in Manilla NSW, Monthly weather by

The daily weather log

April-blooming Deane's wattle

April-blooming Deane’s wattle

After a cool wet week at the end of March, April began warm, especially at night. The night of the 5th, at 18.8°, was the second warmest April night. Rain fell overnight, and the dew point, 18.5°, was an April record. The third week was sunny but cool, and the fourth week nearly four degrees warmer than usual. The last day of the month was suddenly cold (16.9°) and overcast, with drizzle.Weather log April 2014

Comparing April months

The mean minimum temperature was a record 1.7° above normal for the month, warmer than in April 2005, and the mean maximum temperature was also slightly up. The subsoil, after more than two years above normal (by as much as 2.4° in winter 2013), finally cooled down in March and April.
Moisture was near normal, with low rainfall offset by cloudy skies.
Although the total rainfall of 13.0 mm was below the April average (40 mm), it was not unusually low but in the 28th percentile. Taking rainfall totals for more than one month, the greatest shortages are not serious (i.e. not below the 10th percentile). The nine month total (336 mm) is in the 14th percentile. Other totals have higher percentile values, and most totals for 30 months or more are above normal. Pools still survive in Greenhatch Creek.Climate April 2014

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.

 

Rainy Cool March 2013

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log March 2013.

Days and nights were cooler than normal until late in the month. The first day was the coldest: 22.2°. March began with 31 mm of rain on the 1st, and 45.4 mm on the 2nd, but little fell later.

 Comparing March monthsClimate March 2013.

In most ways, the month was like March last year: a bit cool, particularly in the day-time, but warm in the subsoil, and rather cloudy, but not humid. However, there was much more rain.

The total rainfall (84.6 mm) was in the 80th percentile, far above the mean of 53.3 mm. Rainfall totals for groups of months (2 months up to 360 months) are now all above their median values. The 36-month total of 2328 mm is extremely high, near the 36-month record of 2662 mm set in October 1998.

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 2012

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla

“April 2012 like winter 2011”Trends to April 2012.

New raw data for April 2012 anomalies are quite similar to the smoothed values for winter 2011 for all variables but one: subsoil temperature is very high, as it has not been since March 2007.
As in winter 2011, most anomalies are near zero, but skies are very cloudy and, paradoxically, Dew Points are very low.

Record rainfall anomaly

Fully-smoothed data points for October 2011 include a new 13-year record high monthly rainfall anomaly of +38.6 mm (first graph). This beats the record set the previous month by 10 mm, but it will be beaten the following month by a similar margin. Smoothed rainfall anomalies in the last months of 2011 will be well over twice as high as those in the last months of 2010.

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.