Tag Archives: May

Very cloudy days in May 2015

Posted in Manilla NSW, Monthly weather by
Photo of a case moth

A case moth

While there were four frosts (usually 6) that came early in the month, a record number of eleven nights were warmer than 10°. Some were very warm. At 15.1°, the night of the 3rd was the 4th warmest May night. Although the night of the 31st was only 13.0°, since it came so late, that was 9.0° above normal for that date. By contrast, most days were cooler than normal.
The frostier times were sunny, but skies later became cloudy. Finally, days were chilly and overcast. Cloud blanketed the hills, but steady rain (16.5 mm) held off until the very end.

Weather log for May 2015

 Comparing May months

The most remarkable mean value for the month is the daily temperature range: at 12.9°, it is 2.4° below normal. The May months with the narrowest ranges to date, in 2001 and 2014, had ranges of 14.7°, only 0.6° below normal. The narrow temperature range is due to cloudy skies which, at 52%, equal the record for May.
Linked with these figures are a very cool mean daily maximum temperature of 20.2°, and a very warm mean daily minimum temperature of 7.3°. The mean early morning dew point (5.0°) is not high, but higher than in any May month since 2007.
The total rainfall of 30.8 mm is in the 51st percentile. (While the long-term May average is 40 mm, May rainfall in the 21st century has averaged only 21 mm.) Among rainfall totals for more than one month, there are no serious shortages. The lowest percentile value (14th) is for the 24-month total of 1019 mm.

Climate for May 2015

Data. All data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

3-year trends to May 2015

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla
“May 2015: less moist”

Trends to May 2015

May raw anomaly data (orange)

May anomalies moved back towards normal from the cool moist conditions of April for the variables daily maximum temperature, rainfall, and daily temperature range. Cloudiness, however, became extreme, as it had been in the (smoothed data) a year earlier. Daily minimum temperature became very high, keeping the climate in the “Maritime” area. This, again, prevailed just one year ago.

Fully smoothed data (red)

The latest fully-smoothed data anomalies (November 2014) complete the season for spring 2014 (SON). As is most clearly seen in the graph at the bottom right, the daily maximum temperature anomaly (smoothed) reached a minor maximum just above normal in October. Other variables moved little. All were “normal” except the Dew Point anomaly, which had the low value of minus three that has now become normal.

Springtime temperature peaks

Each of the spring seasons of 2012, 2013 and 2014 marked a peak in daily maximum temperature anomalies. Spring 2013 was the hottest, breaking the record for this data set. Spring 2013 also had extreme peaks of lowest rainfall, least cloud, lowest dew point, and highest daily temperature range. This is just what is expected at an extreme El Niño, but there was no El Niño at that time.

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.

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.

May Climate Anomalies Log

Posted in 21st-century climate, Calendar month anomalies, Climate Change, Manilla NSW by

Heat Indicators log for May months

This post is the third in a set for the 12 calendar months. Graphs are sixteen-year logs of the monthly mean anomaly values of nine climate variables for Manilla, NSW, with fitted trend lines. I have explained the method in notes at the foot of the page.

Raw anomaly values for May

Extreme values of May anomalies in this period were:
Daily Minimum Temperature anomaly -3.6 deg: May 2006;
Morning Dew Point Anomaly +3.6 deg: May 1999;
Morning Dew Point Anomaly -3.9 deg: May 2006;
Morning Dew Point Anomaly -3.2 deg: May 2011;
Morning Dew Point Anomaly -4.4 deg: May 2012;
Temperature range anomaly (minus) -3.2 deg: May 2006.

Trend lines for May

Heat Indicators

The trends of all three air temperature anomalies were almost the same, except that anomalies of daily minimum temperature were more negative. All began high in 1999, reached a minimum in 2002, a maximum in 2007, and a minimum in 2011-12. The trend of subsoil temperature was contrary, and generally increasing.

Moisture Indicators log for May months Continue reading →

3-year trends to May 2014

Posted in 3-year climate trends, Manilla NSW by

Parametric plots of smoothed climate variables at Manilla
“Drought status not clear”

Trends to May 2014

May data (orange)

Raw data for May 2014 give mixed signals on whether the drought is fading. Daily maximum temperature is now on the high limit of the normal range and rainfall again well into the “drought” range. However, other variables do not agree: skies were very cloudy, and dew point and daily temperature range were back to normal.

Fully smoothed data (red)

The spring months (SON) of 2013 are now fully smoothed, with some variables showing a drought peak in that season.
Smoothed daily maximum temperature anomaly peaked in October, reaching a record high of +1.39°, beating +1.34° in November 2009 and +1.30° in September-October 2002. Through spring the smoothed rainfall anomaly decreased; it may have reached a minimum in January. Dew point also decreased, the smoothed anomaly reaching a new record low of -4.85° in November, and likely to reach a minimum in December.
Cloudiness reached a minimum in October, and daily minimum temperature and subsoil temperature anomalies had reached maximum values earlier, in July.

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.

Normal values are based on averages for the decade from March 1999. They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 

May 2014 cloudy with warm nights

Posted in Manilla NSW, Monthly weather by

The daily weather log

Yellow berries on a White Cedar in May.

White Cedar in May

May began cold: the 3rd was the 2nd coldest May day of this century, at 11.7°. By the 6th, the 7-day mean temperature was more than four degrees below normal. Within a week, the weather became warm and, by the 25th, the 7-day mean was more than four degrees above normal. The night of the 26th (15.3°) was the 3rd warmest May night of the century. For the first time, May had no frosts at all, and more than half the mornings were cloudy (>4/8 cloud). There were five rain days, two more than usual.

Weather log May 2014

Comparing May months

Air temperatures and the dew point were not far from normal. However, as the second graph shows, they are higher than in May months of recent years, such as 2012. Skies were extraordinarily cloudy, but the subsoil temperature was no longer high.
The total rainfall of 18.2 mm is in the 33rd percentile for May. While this is well below the long-term average of 41 mm, it is on the average for the last 15 years. Taking rainfall totals for more than one month, only the two-month total (31 mm) is a serious shortage (9th percentile). The fifteen-month total (585 mm) is in the 12th percentile. Other totals have higher percentile values, and most totals for 36 months or more are above normal. Pools still survive in Greenhatch Creek.

Climate May 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.