Normal Climate in Summer 2008-09

 

Weather log summer 2008-09

For most of the summer, 7-day average temperatures got steadily warmer. From 4° below normal in mid-December they rose to 4° above normal in early February. They then crashed to 5° below normal before recovering. Two days exceeded 40°: February 6th (40.1°) and February 9th (40.9°). In ten summers, 19 days have exceeded 40°, the hottest being 42.0° on 21/2/04.
This season had the coldest summer day so far this century: February 14th 2009, with 17.8°. That is 15.3° below normal (it would be normal in winter, not summer)!

NOTE. This is the daily maximum reading that is furthest below normal in the ten-year record from March 1999. There have been only 23 days when the maximum was more than 10° below normal. Only 18 days were more than 8° above normal. The furthest above normal (by 10.5°) was the reading of 38.8° on November 10th 2002.

Humidity was low both in the early cool spell and in the later hot spell. At both times the daily range of temperature was high (17°) and the skies mainly clear.
There were 23 rain days, which is normal and far fewer than the 33 rain days last summer. Dry spells (with falls less than 1 mm) were long: 21 days from the 30th of December, and 16 days from the 25th of January. February the 15th was the wettest day, with 51.2 mm, and the summer total was 228 mm.
The number of overcast mornings (12) was normal for summer, but the number of cloud-free mornings (17) was very low, as it was last summer (13).


All mean temperatures (daily maximum, mean, and minimum) were normal this summer. They were much higher than last summer, with the daily maximum a remarkable 2.8° higher. The mean morning Dew Point was also normal.

The total rainfall of 228 mm is very close to the long-term summer average of 227 mm. It is on the 54th percentile.
At 38% cloudy mornings, this summer was cloudy, but not extremely cloudy like last summer (53%).
The summers of 05-06 and 07-08 were both very wet (319 mm and 311 mm). They differed in other ways: summer 05-06 was hot, humid and not cloudy; summer 07-08 was cold, not humid, and extremely cloudy.

Climate for summer 2008-09

 

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

December 2008 normal weather again

The daily weather log

Weather log December 2008

Unlike last December’s cool, humid, cloudy and rainy weather, this December’s weather was very close to normal in every way. There was a time in the middle of the month when the 7-day temperature was rather low, with low humidity and clear skies, but this was balanced by warmer, moister times.
Days were slightly cooler than average, but the very hottest day was remarkably cool: only 35.0°. Only two Decembers in a decade failed to make 35°. Even October and November this year had days warmer than 34°!
There were eight rain days, the wettest having 38.2 mm.

 Comparing December months

Climate December 2008

All mean temperatures, including the Dew Point and the daily range, were within one degree of the December average. The rainfall total (77 mm) was just 3 mm above the long-term average for the month.

Most rainfall totals for groups of months have risen yet higher. The total for 2 months (November and December) is in the 91st percentile, 3 months in the 93rd, 4 months in the 91st, 5 months in the 88th, and 6 months in the 83rd percentile. Totals are now above the median for all periods up to 72 months.
The year 2008 had spring rainfall nearly 100 mm down and autumn rainfall 130 mm up. The total of 720 mm is 68 mm above average, and on the 64th percentile for annual figures. The year 2007 had been a little wetter, at 740 mm. In broad terms, only one third of all years were wetter than these.


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.

 

November 2008 cool and very wet

The daily weather log

Weather log November 2008

This November was like last November, but wetter. Again, a sunny dry week separated times of overcast rainy days.
Sudden cold changes, which had come twice in October, came again on the 8th, 17th, and 22nd. The last was severe. The maximum on the 23rd was nearly 12° below normal. The temperature that day did not rise above 15° until 5 pm!
Steady soaking rain on the 3rd amounted to 44 mm. A long spell of six rain days from the 17th brought another 48 mm. It began as persistent drizzle but included storms (one with 15 mm size hailstones). These days had low cloud and high humidity. Extremely low humidity (Dew Point 0.1°) came with the cold change, but dew points rose to a peak of 17.4° on the 29th. Over 26 mm of rain fell that day.
Manilla missed two heavy rainstorms of 80 mm each that swept through Tamworth at 10 am and 10 pm on the 28th. There was flooding at Tamworth, at Carroll Gap, and on the plain east of Gunnedah. The Namoi River at Manilla also rose due to rain near Bendemeer.

 Comparing November months

Climate November 2008

Days were the coolest in ten Novembers. However, the mean daily minimum was high, making the daily temperature range (12.4°) even narrower than last November. This agrees with high values for cloudiness and dew point.

The rainfall total, 132 mm, is far above the long-term November average of 67 mm, but that is now common. Five of the last ten Novembers had 110 mm or more. This month and November 2000 were equal ninth wettest on record, and November 2001 (133 mm) eighth wettest.
The rainfall totals for groups of months get higher and higher. The total for 2 months (October and November) is in the 94th percentile, 3 months in the 92nd, 4 months in the 86th, 5 months in the 80th, and 6 months in the 81st percentile. Totals are now above the median for periods up to 72 months with only one exception: that for 9 months is in the 47th percentile. The six-year total rainfall is now 100 mm more than in six average 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.

 

Rain storm in October 2008

The daily weather log

Weather log October 2008

October began fine and very warm, with 32° days and 17° nights. Wet days from the 4th to the 6th brought warm nights at first, followed by a very cold day (19.2°) and night (4.4°). From the 10th to the 21st normal temperatures prevailed. Then a strong southerly made days and nights 10° colder again. The night of the 23rd was 9.0° cooler than normal. The month was frost-free, however.
Calmer, sunny weather returned, with the last day the hottest, at 34.5°.
The seventh rain day of the month brought 52 mm. Rain drove in horizontally during a south-westerly gale after 5pm on Tuesday the fourteenth. This was reported, with a photo of broken trees, in the “Manilla Express” (21/10/08). The gale was a gustfront fanning out from the downburst of a thunderstorm. Storm gustfront gales in this area often blow from the south-west. Within minutes, cold air is dumped on the ground from a height of more than 5 kilometres. The downburst brings the strong south-west winds found there down to ground level.

 Comparing October months

Climate October 2008

Unlike last October, which was remarkably warm and had a high daily temperature range, this October had temperatures near normal, with rather warm nights bringing a lower daily temperature range. Both humidity and cloudiness were slightly above normal.

Manilla has had a lot of rain.
The high rainfall total, 97 mm, is on the 83rd percentile for October. Only 21 recorded Octobers were wetter, including October 1999 (104mm) and 2000 (110 mm). Most rainfall totals for several months together are now above the median (the 50th percentile). The total for 2 months (September and October) is in the 82nd percentile, 3 months in the 71st, 4 months in the 60th, 5 months in the 63rd, and 6 months in the 50th percentile. Rainfall totals for longer periods, up to 60 months, are above the median with only two exceptions: the totals for 9 months (42nd percentile) and for 30 months (35th percentile).


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.

 

September 2008 had good rain

The daily weather log

Weather log September 2008

September was a month of changeable weather. It began with normal temperatures returning after a very cold August. Then there was a spell of fine cold weather, with the seven-day mean falling back to 12°, another much warmer fine spell at 18°, and a third at normal temperature (16°).
Between the fine spells there were seven rain days, including very good falls of 19.8 mm on the 1st and 19.0 mm on the 23rd. The total was 66.2 mm.
Despite all the changes, temperatures were not extreme. Only the wet, overcast day on the 6th, reaching 14.3°, was 8° below normal. The hottest day, the 20th, reached 31.5°. Mild frosts on the 10th and 11th did not fall below zero in the screen.
Having twelve mornings completely free of cloud is normal for September. (In 2003, the number was 23!) A milky haze persisted from the 16th to the 22nd, perhaps caused by cypress-pine pollen.

 Comparing September months

Climate September 2008

 

The mean of the daily mean temperatures was normal. The mean of the daily maxima was down, and that of the daily minima was up. This made the mean daily temperature range (15.0°) equal lowest September value of the decade, well below the average of 16.5°.
The humidity (early morning dew point: 5.6°) and percentage of cloudy mornings (30%) were a little higher than usual.
The rainfall total, 66 mm, is on the 82nd percentile for September. This is far above the average (41 mm), but less than the 100 mm of September 2005. Last September, by contrast, had only 2 mm: the third driest on record.
Totals for several months together now show no serious shortages. The total for 2 months (August and September) is in the 52nd percentile, 3 months in the 41st, 4 months in the 47th, 5 months in the 32nd, and 6 months in the 22nd 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.

 

3-year trends to August 2008

Parametric plots of smoothed climate variables at Manilla
“Years with unusual trends”

Trends to August 2008

These graphs, ending with raw data for August 2008, show fully-smoothed data from September 2005 to February 2008. They include all months of the calendar years 2006 and 2007.
Smoothed daily maximum temperature anomaly (X-axis on all graphs) began 2006 high in the “normal” range, fell to normal by June, and rose again to +0.63°  in November and December. It then fell from high to very low through 2007, reaching the record low value of -1.61°  by February 2008. (Note added: This record low maximum temperature anomaly stood for only 19 months, until September 2010.)
Smoothed rainfall anomaly peaked at +20.6 mm in November 2005, fell rapidly to -11.7 mm in June 2006 and slowly to -14.6 mm in October 2006. It rose again to just above normal by February 2007, and changed little in the following year.
Smoothed percent cloudy mornings followed a similar course to that of rainfall but, as temperature fell through 2007, cloudiness (unlike rainfall) increased, as is normal,  along the blue trend-line.
(Note added in May 2014: Although the minimum value of the cloudiness anomaly in August 2006 (-7.7%) is less negative than the record minimum in August 2002 (-11.3%) (or even than the minimum in February 2005 (-9.1%)) it is more negative than any later value. No smoothed negative values at all were recorded in almost seven years between February 2007 and October 2013.)
Smoothed dew point anomaly also followed a similar course to that of rainfall but, unlike cloudiness, actually declined as temperature fell during 2007. Temperature range anomaly moved like dew point anomaly.
Daily minimum temperature mainly varied in the same sense as daily maximum temperature, but at a higher rate. As an exception, from January to June 2007, it rose slightly as maximum temperature fell. That moved the curve towards a more “maritime” climate for the rest of the time. Subsoil temperature anomaly moved in a similar pattern.

Unusual trends

Through the years 2006 and 2007 shown here, the climate moved as much along the axis from top left to bottom right, as along the usual axis from top right to bottom left. It departed from the typical Quasi-biennial oscillation of “droughts and flooding rains”*. (Note added: The extreme negative maximum temperature anomaly of February 2008 was the only one on this record that was not linked to an extreme positive rainfall anomaly.)
(Note added concerning global temperature: At this time there was a sudden major cooling in mean air temperature, both locally and globally. This linked post  shows that, when 37-month averages of global and local values are plotted, mean temperature fell from a peak in April or May 2006 to a trough in October 2007, breaking the global warming trend. The global (GISS) value fell by 0.074° (and the Manilla value by 0.48°). The connection is enigmatic. The unusual trends shown here do not match the dates of the cooling event, but come mainly before or after it.)

* By arrangement with the Licensor, The Dorothea Mackellar Estate, c/- Curtis Brown (Aust) Pty Ltd.

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.
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.

(Note added in May 2014: A much later post titled “3-year trends to May 2010” is the first of a consecutive series of parametric plots, updated monthly at the time of observation and originally posted elsewhere.
This earlier data was not edited in this form at the time.
To display all existing fully-smoothed data points at least once, I have prepared these back-dated posts in the same format for:
“3-year trends to August 2002” which includes smoothed data September 1999 to February 2002, covering the calendar years 2000 and 2001.
“3-year trends to August 2004” which includes smoothed data September 2001 to February 2004, covering the calendar years 2002 and 2003.
“3-year trends to August 2006” which includes smoothed data September 2003 to February 2006, covering the calendar years 2004 and 2005.
“3-year trends to August 2008” (this post) which includes smoothed data September 2005 to February 2008, covering the calendar years 2006 and 2007.
In these back-dated posts the anomaly values depend on climate normals that are based on the decade ending February 2009, and were thus not available until after that date. I have written the posts as if they were available at the time.
In places I have written some “Notes added in May 2014” (like this) commenting on how values observed at that time relate to more recent events.)

 

 

August 2008 very cold and cloudy

The daily weather log

Weather log August 2008

The second week of August was the coldest week of the year. Temperatures by day and night were six degrees below normal. In the whole month few temperatures were above normal. Only six days got above 20°, compared to the usual twelve. The very last night soared to nine degrees above normal.
However, no days or nights were particularly cold. Although the 13th was the coldest morning of the winter at -2.8°, it was only a little lower than -2.7° on the 11th and 20th (and also on the 12th of July).
Most days had very dry air, with morning dew points below zero. Despite that, there was a lot of cloud. The number of mornings free of cloud was only five, the fewest in ten Augusts.
There were nine rain days spaced through the month, totalling 31.6 mm.

 Comparing August months

Climate August 2008

All the mean temperatures (daily maximum, daily mean, and daily minimum) were the lowest for August in a decade. The mean was over two degrees below normal.

It was a frosty month. In ten Augusts, none had as many minima below -2° (6) or below zero (14) as this one, but August 2005 had more total frosts (21 versus 18) counting minima below +2.2° in the screen.
Mean humidity (morning dew point) was extremely low. At -0.4°, it was over two degrees below normal. In the decade, only July 2002 had drier air, with a mean morning dew point of -3.1°.
There were more cloudy mornings (55%) than in any August of the decade. Five of the seven cloudiest months of the decade have come within the last ten months: Nov ’07, Dec ’07, Feb ‘08, Jul ’08, and Aug ’08. All had 50% or more cloudy mornings, almost twice the decade median of 27%.
The rainfall total, 31.6 mm, is on the 46th percentile for August, and below the average (40 mm). Totals for several months together are much the same as a month ago, but the serious shortage has moved back to the six-month total. The total for 2 months (July and August) is in the 28th percentile, 3 months in the 41st, 4 months in the 25th, 5 months in the 17th, and 6 months in the 7th 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.