May 2020: still cool and moist

Weather log for May 2020

[Note.
Due to illness, the first seven days of this month were missed for some Manilla values. No actual values were noted for cloud or soil temperature. Daily maximum and minimum air temperatures were estimated by regression on values from Tamworth Airport Automatic Weather Service.]

May weekly mean temperatures were slightly below normal, except in the final days.
The weather varied with three rainy periods about the 1st (20.0 mm), 10th, and 21st. At these times, skies were cloudy, dew points were high, nights were warm and days cold. The daily maximum temperature on the 23rd (10.7°) was the lowest for May in the new century. The first frost came on the 11th May, near the median date for it.

Comparing May months

The climate this May marked a return to the cool and moist conditions of May 2015. It was quite different from May 2018, which was warm and dry, and from May 2019, which was warm and wet.

While the mean monthly temperature (13.0°) was rather low, the mean daily maximum (19.9°) was the lowest on record for May. The mean daily minimum (6.0°) was normal.
The rainfall total of 38.4 mm was at the 59th percentile for May, which was near the average (41 mm). Early morning dew point (4.8°) was also near normal, while moister climate was shown by high cloudiness (42%) and narrow daily temperature range (13.9°).

Drought

I will report separately on the on-going drought.


Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available. Recording resumed on 20 July 2019. The gauge failed again during February (25/02/2020 ), but was repaired on 11/3/20.
My estimates of early morning dew point have drifted anomalously low. From August 2019, I use data from the Tamworth Airport published graphs.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

3-year trends to May 2020

May, like March and April, continued cool

May raw anomaly data (orange)

Current raw anomaly values for May appeared very little changed from those of March and April. However, as noted below, many values are estimates only.

Temperatures

Daily maximum temperature anomaly (all x-axes), which had been very high until January, remained near -1.5°.
Daily minimum temperature anomaly (lower left): stayed at normal.
Subsoil temperature anomaly (lower right): stayed at normal.

Moistures (moist is at the bottom)

Rainfall anomaly (upper left) stayed near normal.
Cloudiness anomaly (upper right): remained high.
Dew point anomaly (middle left): remained normal.
Daily temperature range anomaly (middle right) stayed low, near -1.5°.

 Fully smoothed data values (red) 

Fully-smoothed data is now available for the spring season (SON) of 2019. Taking the season as a whole, smoothed daily maximum temperature anomaly peaked (at the 21st-century record value of +2.21°) in October, while daily minimum temperature rose, and subsoil temperature fell. A steady movement away from extreme drought affected rainfall, cloudiness, dew point, and daily temperature range (lower).

[Note.
Due to illness, 45 days were missed for some Manilla values, from 23/3/20 to 8/5/20. No values were noted for cloud or soil temperature; daily maximum and minimum air temperatures were estimated by regression on values from Tamworth Airport Automatic Weather Service.]


Notes:

January data points are marked by squares.

Smoothing Continue reading

May 2019 had the warmest nights

Keepit Dam boom, May 2019

The month began warm, with the night of the 2nd being, at 18.0°, the warmest May night of the new century. There was a second warm spell nearly four degrees above normal about the 20th.
The first frost (by my reading) came on the 12th of May this year, and on the 15th of May last year. The middle date of first frost is May 13th.
There were three rain days (usually four) but nearly all the rain (61 mm) was recorded on the 4th.

Weather log May 2019

Comparing May months

The mean temperature this month (14.6°) was high, but not as high as in May 2007 (15.1°). However, the mean daily minimum temperature (8.1°) was the warmest for May in the new century: above normal by 2.3°.
A rather narrow daily temperature range (13.1°) and high percentage of cloudy days (45%) showed moisture above normal.
The (estimated) rainfall total of 61.8 mm was very high, in the 75th percentile. Because no rain at all had fallen in April, the total for the two months together reached only to the 26th percentile.

Climate for May 2019

Drought

The on-going unprecedented drought is reported in another post.


Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available.  Since no 9 am readings have been recorded since August 2018, I have substituted my non-standard gauge readings for all days.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

3-year trends to May 2019

May days not warm

3-year trends to May 2019

May raw anomaly data (orange)

In May 2019, the anomaly of daily maximum temperature returned to zero after years of positive values. Both daily minimum temperature and subsoil temperature anomalies were very high. Moisture anomalies, reflecting the high rainfall value (+21 mm), were low on the graphs (away from drought), but dew point was not as far down as “normal”.

 Fully smoothed data (red)

Fully-smoothed data now include the spring season ending November 2018.
Both daily maximum and daily minimum temperature anomalies were very high and rising. The minimum was rising faster and broke the record of +1.65°. Subsoil temperature anomaly, due to a phase lag, was normal and still slowly falling.
Moisture indicators in this spring were inconsistent. Rainfall anomaly decreased slowly to a new (20th century) record of minus 29.7 mm. The dew point anomaly was also low, but rapidly increasing. Both the cloudiness and the daily temperature range were normal.


Notes:

January data points are marked by squares.

Smoothing

Smoothing uses Gaussian functions.
For fully smoothed data the function has a Standard Deviation of 2.5 months, it spans 13 monthly data points, and has a half-width of 6 months, which suppresses cycles shorter than 12 months. For partly smoothed data, the span of the function is reduced to 11 months, 9 months and so on.
Continue reading

May 2018 third driest

Sunset clouds

the heavens’ embroidered cloths

Temperatures did not stray far from normal. The first (black) frost that I observed was on the 15th, near the normal date for it (13th May). That began a week of sunny skies and very dry air.
There was only one rain day. An early morning shower gave a reading of 1.2 mm on the 30th.

May 2018 weather log

Comparing May months

The May months in 2018, 2017, and 2016, as well as in 2014, were all warm. The average temperature was more than half a degree above the normal value of 13.3°. While May 2017 was warm, wet, and humid, May 2018 was warm, dry, and arid. The air was exceptionally dry, with the mean early morning dew point (0.0°) the lowest for May, and the relative humidity at that time 68% instead of the usual 80% to 90%.
The rainfall total of 1.2 mm was third driest for May, equal with May 2002, but not as dry as May 2006 ( 0.2 mm). Only May 1927 was drier, with zero. May rainfall values have been low in the 21st century, with an average of 23 mm, compared to the long-term average of 41 mm.

Climate in May months

Rainfall Shortages

Last month, April 2018, had only two rainfall shortages classed as “serious” (below the 10th percentile): those for durations of five years and six years. Since then, more shortages have appeared. Those five-year and six-year shortages remain, but there are now serious shortages for durations of five months and twelve months, and severe shortages (below the 5th percentile) for one month, two months and three months. The current three-month total (45 mm) is at the 4th percentile.


Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available.  The gauge, which had last reported on 24 September 2017, came on line again on the 16th of March. However, during the month of May eleven daily readings were blank. I have substituted my own gauge readings, which were all zero.

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