3-year trends to July 2012

Parametric plots of smoothed climate variables at Manilla

“Back towards very wet”Trends to July 2012.

Most July 2012 anomalies are close to normal, and like those of the month before. Rainfall, however, is again very high, as in the spring and summer, and daily min temp has gone from very low in May to very high.
The subsoil remained extraordinarily warm. (Why?)

Fully-smoothed data (in red) show that the 13-year record low monthly max temp anomaly of October 2010 (-1.96 degrees) was beaten in January 2012, with a new low value of -2.03 degrees, perhaps to be beaten in the following month. At Manilla, the “flooding rains” climate phase of 2011-12 was very much wetter, and somewhat cooler than that of 2010-11.

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.

Very Wet July 2012

The daily weather logWeather log July 2012.

As in June, most weather features in July were normal, except for very warm nights with the heavy rain in the second week. Sixteen mornings were frosty, one down to minus three degrees. There were several early fogs in the valley.
Of seven rain readings, most were heavy. But the 29.6 mm value included three days.

 Comparing July monthsClimate July 2012.

Other than rainfall, there is only one variable that is not on the July average: the subsoil temperature at 750 mm is again extraordinarily warm, at 16.9°, 3.2° above normal.
The rainfall total of 91.4 mm is in the 94th percentile. Only eight July months have ever been wetter. However, July 1984, at 171 mm, was nearly twice as wet. The 12-month total to the end of July (1020 mm) is extreme. In the last 50 years, only three 12-month totals have been higher: September and October 1998 and February 1984.


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 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.

Dry air and little rain in July 2011

The daily weather logWeather log July 2011.

Despite a series of cloudy cold days in the middle of the month, most features of the weather in July were normal. Days got as warm as 20° at each end of the month, and never went lower than 11.7°. Nights were neither very warm nor very cold. There were 17 frosts, the coldest being -3.7°.
Humidity and rainfall recall the drought year of 2002.
Extremely low humidity was shown by the early morning Dew Point on the 12th, of 6.2°. This was the lowest July value since 2002, which had four lower values, down to 6.7°.
The highest rainfall reading was only 4 mm, recorded on the 20th. Four rain days totalled 6.4 mm.By the end of the month there had been 39 days with less than 5 mm of rain.

 Comparing July monthsClimate July 2011.

Mean temperature readings were normal. The mean early morning Dew Point (- 0.6°) was the lowest July value since 2002 (- 1.4°).
For frosts, this month was normal. Since 1999, the most frosty July was in 2002, with 27 frosts, down to -5.1°. The least frosty was 2010, with 12 frosts, down to only -1.4°.
The rainfall of 6.4 mm is very low: on the 8th percentile for July. Only ten Julies in 127 years have been drier. (July 2002 and July 1940 were equal driest, at 1 mm.) Rainfall totals for 2, 3, 4 and 5 months are in the 5th, 10th, 9th and 10th percentiles respectively. Percentile values lower than 10 are serious rainfall shortages. Totals for larger groups of months continue to be near normal.


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.

 

July 2010 Rain Twice Average

The daily weather logWeather log July 2010 Manilla

July began cold. The 2nd, with a maximum temperature of 9.1°, was the coldest July day in the record from 1999. The only two colder days were: 8/06/07 (8.8°), and 20/06/07 (8.3°).

Two warm spells followed, marked mainly by nights that were very warm for mid-winter. The minimum on the 12th (11.8°) was 10° above normal, and that on the 31st (13.5°) was 11.3° above normal. Colder nights included twelve mild frosts, the fewest on record.
There were 13 rain days spread through the month. The reading of 17.2 mm on the 29th was topped by 34.2 mm on the 31st.

“Normal Temperature”

Each Manilla monthly weather graph has dashed curves to show the temperatures that are normal for each day of the year. They are harmonic curves matching 10-year averages from March 1999. On this July graph, the lowest values are marked with a double “X”. Winter cold is due to lack of heat from the sun, which yields least heat on the 21st of June (the winter solstice). On that day the sun is lowest and shines the shortest time. However, it takes many days for the air to cool down. On average, the coldest day in Manilla comes 17 days later (July 8th) and the coldest night 22 days later (July 13th). Manilla’s coldest day and night follow the solstice with an unusually short lag time. (See Wikipedia: Seasonal lag.)

See the monthly weather report for January 2010 for the highest normal temperatures of the year. These relationships are shown on a graph here.

Comparing July monthsClimate July 2010 Manilla

Due to cloudy nights, the mean daily minimum temperature (4.6°) was by far the highest in the 12-year record for July, and 2.4° above the average. Because the mean maximum temperature was normal (16.9°), the mean average temperature was also high (10.8°). The mean daily temperature range (12.3°) was the narrowest in the July record.

Very high humidity was shown by a mean early morning Dew Point of 4.6°, higher than any since July 1999 (5.7°). The percentage of cloudy mornings (61%) was the highest, not only for July months, but for any month in this record. Nineteen mornings were completely overcast.
The rainfall of 79.8 mm is in the 90th percentile for July: only 12 July months have been wetter. It is close to double the long-term average of 41 mm. As a result, total rainfalls for the last two months and three months are now above the median. No serious rainfall shortages remain. The worst shortages are far from serious: the 15-month and the 9-year totals are both in the 14th 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.

July 2009 getting short of rain

The daily weather logWeather log July 2009

Apart from a scarcity of rain, and an abundance of cloud, the weather in July was very much as usual. One day reached 23°, another only 12°. There were 18 frosts (normally 17), but no night was colder than -2° (normally 4 nights are). Fog filled the valley on the 28th.
There had been twenty-three days without 5 mm of rain when 9 mm fell on the 16th. In six rain days the month’s total was 21.3 mm. This is well below the median for July (35 mm): it is in the 25th percentile.

 Comparing July months

Climate July 2009

All mean daily temperatures for the month were normal.
There is a serious shortage of rain in the five months to date: the total of 138 mm is on the 10th percentile. Five-month totals below the 10th percentile are rare in recent years: July 2008 (9th percentile), August 2006 (9th), May 2005 (5th) and September 2003 (7th).
(Very much drier 5-month conditions prevailed in 2002: November had a severe rainfall shortage (in the 2nd percentile) while July, August, September and October had extreme rainfall shortages, in the first percentile. September 2002 had the lowest 5-month total (61 mm) in 75 years.)


Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperature and other data are from 3 Monash Street, Manilla.

 

July 2008: more cloud, less frost

The daily weather log

Weather log July 2008

With 52% cloudy mornings, this was the cloudiest July (and the fifth cloudiest month) in a decade.
There were no long warm or cold spells, so the seven-day mean temperature scarcely changed until the cooler final days. Yet each day’s temperatures were quite different from the day before. Wednesday the 9th was the 4th coldest day of the decade. It reached only 9.8°, and Monday the 28th, at 11.3°, was not much warmer.
Five nights were warmer than 8°. They were separated by cold nights, but there were only fourteen frosts, the coldest, on the 12th, being 2.7°. Widespread fog on the 15th did not lift until 11 am, and there was thick fog in the valley on the 26th.
Eight rain days were scattered through the month. The wettest day had 9.4 mm, and the total was 33 mm.

 Comparing July months

Climate July 2008

The mean daily maximum and daily mean temperatures for the month were normal but, on the average, nights were warm. As a result, the mean daily temperature range, 13.6°, was the narrowest in ten July months. Sunny, frosty, droughty July 2002 had a range of 18.5°: more than 30% wider! (The month with the narrowest mean temperature range for the decade was June 2007, with 10.9°. That was also the cloudiest month.)

July usually has about 17 frosts. This month’s total of 14 made it the least frosty July this century. July 1999 had only 13 frosts, with none below -2°.
Humidity (early morning dew point) was normal for the time of year.
The rainfall total is not far below the average: 33 mm is in the 46th percentile for July. The total for this June and July together (98 mm) is better than usual: in the 52nd percentile of two-monthly totals. Not so good are the three-monthly total (112 mm) in the 30th percentile and the four-monthly total (132 mm) in the 20th percentile. Worse, the five-month total (134 mm) is only in the 8th percentile, due to the 2 mm rainfall of March. The six-month total is much better (in the 29th percentile). Rainfall totals for longer periods are normal.


Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperature and other data are from 3 Monash Street, Manilla.