Summary
for August 2005
=======================
HEADLINE:
ABOVE AVERAGE RAINFALL. WARM/MAINLY DRY SECOND & LAST WEEKS
(last
updated: 01/1500 SEPTEMBER)
Location:
Tawfield/Wooden Hill area of SW
Bracknell, Berkshire, UK
Altitude
80 m (other location details see elsewhere on web site.)
(temperatures
[standard screen] degC; rainfall/melted snowfall mm; snow depths cm; )
Readings
taken at 0900 and 1800 UTC. Where the NIGHT maximum
or DAY
minimum are significantly different from figures hereunder, this will be noted
in the accompanying text summary. There are now two mean daily temperatures
shown: the first is the mean of the average day maximum and average night
minimum (A), and the second is the average of the 24hr maximum and 24hr minimum
(B .. as kept formerly) .. the anomalies are shown for this latter figure from
1971-2000 estimated Long Term Averages. Rainfall is credited to the 24hr day
beginning 0900 UTC.
=================================
TEMPERATURES
ETC.
Highest
day maximum (date):... 29.0(31)
Highest
24hr maximum (date):.. 29.0(31)
Lowest
night minimum (date):... 08.6(07,08)
Lowest
24hr minimum (date):... 08.6(07,08)
Lowest
overnight grass minimum (date):... 06.9(07)
[
number of days grass minimum < 0degC: ... 00 ]
[
Lowest day maximum (date):... 16.3(24)]
[
Highest night minimum (date):... 15.3(31)]
A. Mean
Day (09-18Z) maximum: ... 22.5
A. Mean
Night (18-09Z) minimum: ... 11.8
A. Mean
of Day Max & Night min: ... 17.1
B. Mean
24hr maximum:... 22.5
B. Mean
24hr minimum:... 11.8
B. Mean
of 24hr max & min:... 17.1 [-0.1 anomaly on eLTA of 17.2degC]
(data
below relate to 24 hr day beginning 09Z on date given)
Nr of
days minimum at 09UTC <0.0degC:00
Nr of
days maximum at 09UTC >=21degC:22
Nr of
days maximum at 09UTC >=25degC:07
Nr of days
maximum at 09UTC >=30degC:00
(Notes
relating to temperature & allied observations:
25th:
temperature fell from day max. 17.4 to day min. 12.0 associated with
thunderstorm (see details below);
=================================
PRECIPITATION
(PPN/mm)
Total
rainfall/melted snow etc:... 61.2 [113%
of eLTA of 54mm]
Highest
24hr total:............... 10.9(22)
No.
days PPN total >= 0.2:10
No.
days PPN total >= 1.0:10
No.
days PPN total >=10.0:02
No.
days PPN total >=25.0:00
(Notes
relating to precipitation & allied observations:
1st:
r(slight)/r early hours to ~07Z [credited to July's rainfall total]; pr(slight)
1710-1730Z;
3rd:
r(slight), tempo r 02-03Z;
4th:
r(slight) began 1840Z, continuing as ocnl r/dr through night 4th/5th,
ceased
by about 05/0830Z;
5th:
further dr(slight/moderate) 09-0915Z;
11th:
pr(slight/moderate), tempo pR/h(small) 1825-1850Z;
13th:
r(slight)/r from 1245Z, with dr(slight/moderate) by 18Z, csd by ~1820;
13th/14th:
pr(slight)/pr overnight & morning;
14th:
pr(very light) PM;
19th:
r(slight)/r from ~02Z, bec mainly r(R) from 0510Z (with distant t 0420-0525Z)
until 1210Z, then slight until 1430Z, when ceased; pr(slight) evening;
22nd:
dr(slight) 05-06Z; r/R from ~0820Z to 09Z, then dr/r, ocnl dr/r(slight) much of
day – ceased by 1630Z, but idr(slight) 1745Z, dying out slowly early evening;
24th:
ir(slight) from 0840Z, bec r(R) soon after 0905Z, remaining mainly moderate
until becoming dr(slight)/r(slight) by~ 16Z, csd ~ 1715Z;
25th:
pr(very light) ~05Z; pr(slight) from early afternoon, with thunderstorm / rain
/ hail 1440Z-1530Z (see Remarks below for details);
26th:
pr(very light) 1330-16Z;
31st:
r(slight) from ~1750Z; first t heard 1840Z, with tl(slight), ocnl tl between
1910Z & 2000Z, accompanied by short-period of r/R 1930-1945Z, otherwise
r(slight), ocnl r with the storm (see notes below)
=================================
OTHER
TOTALS
Number
of days thunder heard: (dates).. 03 (19,25,31)
Number
of days hail < 0.5cm diameter:.. 01
Number
of days hail >=0.5cm diameter:.. 01
Number
of days snow/rain & snow:....... 00
Number
of days snow lying at 09UTC:.... 00
Deepest
snow cover (date,s):........... -
Number
of days fog (visibility < 1km @ 09UTC).. 00
=================================
Additional
comments on the weather in August, 2005
[2nd]:
fog (thick/wet) early hours, cleared by ~06Z – produced a measured 'trace' in
rain gauge;
[11th]:
just a few small, opaque hailstones ~1830-1835Z;
[19th]:
thunder heard (distant and/or medium-level), infrequent, 0420-0525Z;
[25th]:
(notes re: thunderstorm/hail)
1440Z
.. tl(slight)
1450Z
.. tl r(slight) h(slight)
1455Z
.. tlrh [see below]
1500Z
.. tl r(slight) h (slight)
1504Z
.. tl(slight), precipitation ceased
1530Z
.. thunder last heard 10 mins previously.
Hail:
6-8 mm initially, becoming 8-15mm for a short time ~1455Z (maximum irregular
diameter) 20mm. Hail white/opaque/soft-coated – mostly spherical, but largest
stones conical.
[31st]:
(notes re: thunderstorm during evening)
1840Z
.. t heard (NO lightning seen/probably medium-level at this time)
1910Z
.. tl(slight) from southwest (sharp trough line)
1920Z
.. tl (lightning CC or IC from here)
1930Z
.. tl(slight) r(slight), soon r with CC lightning
1940Z
.. tlR (with two local CG discharges)
1945Z
.. tl(slight)r, becoming mainly r(slight), ocnl r
2000Z
.. thunderstorm effectively ceased (passed well to N), light rain continues,
total rainfall this storm not great at 2.2mm
2100Z
.. very distant (to N/NNE) 'sheet' lightning still visible
...
these data can also be viewed at:-
http://homepage.ntlworld.com/booty.weather/metinfo/wxdata/climintro.htm
Tn
Tx Tg RR
Tn Tx RR
RR24hr Remark code (below)
(09Z) (09Z) (09Z)(18-09Z) (18Z) (18Z)
(09-18Z) (from 09Z today)
01 13.7
19.5 13.4 08.8
15.3 21.1 tr
tr -
02 12.2
18.3 10.6 tr(fe)
18.3 24.6 -
00.1 A
03 14.5
22.0 13.2 00.1
19.4 23.3 -
-
04 12.0
21.6 10.9 -
18.6 22.4 -
08.2
05 13.6
20.7 13.2 08.2
17.3 22.0 tr
tr
06 09.7
20.2 07.9 -
16.3 19.9 -
-
07 08.6
18.7 06.9 -
15.6 21.6 -
-
08 08.6
21.0 07.2 -
16.2 22.7 -
-
09 10.4
22.4 08.6 -
17.1 25.2 -
-
10 12.1
24.1 10.4 -
18.1 24.3 -
-
11 12.5
21.9 10.7 -
19.6 25.7 -
02.3
12 12.6
23.7 11.3 02.3
17.1 22.0 -
-
13 10.5
20.2 08.8 -
16.7 20.8 05.4
07.6
14 11.6
17.0 10.2 02.2
15.7 20.8 tr
tr
15 09.6
19.0 07.4 -
16.1 23.8 -
-
16 09.9
22.5 07.9 -
17.2 24.7 -
-
17 10.8
23.8 08.5 -
18.5 25.6 -
-
18 12.6
24.8 10.0 -
20.1 26.9 -
06.0
19 14.8
25.6 14.4 06.0
15.1 17.9 04.3
04.5
20 12.7
17.7 11.5 00.2
15.9 20.0 -
-
21 13.4
19.1 10.6 -
17.0 24.2 -
02.7
22 13.6
23.1 11.7 02.7
16.2 18.7 10.5
10.9
23 10.3
16.4 08.3 00.4
15.4 21.6 -
tr
24 12.8
19.4 12.0 tr
14.6 16.3 10.4
10.4
25 11.1
16.1 09.8 tr
12.0 17.4 06.3
06.3
26 09.2
14.4 08.1 -
14.1 18.7 tr
tr
27 12.5
16.3 11.0 -
16.3 21.1 -
- B
28 11.5
19.3 10.0 - 16.6
23.4 - -
29 12.0
21.8 10.4 -
17.3 25.0 -
-
30 12.4
23.5 10.4 -
19.8 25.9 -
-
31 15.3
24.5 12.7 -
22.0 29.0 tr
02.2
Remarks:
A.
night max.(18.3) occurred 02/0900Z
B. night
max.(16.3) occurred 27/0900Z
Number
of occasions (24hr periods) THIS YEAR (2005)
maximum
temperature >= 21degC (70degF) = 60
minimum
temperature >= 16degC (61degF) = 08
[MONTHLY
NOTES]
TEMPERATURE:
>
With an anomaly (on the 24hr max/min dataset) of –0.1degC, August 2005 was the
first month since December 2004 with a negative anomaly, though the figure is
not exactly significant. It does hide the fact that for a large portion of the
month, the anomaly was running two or three tenths of a degC below average, and
only the two hot days at the end dragged it up near-average.
The
reason for the deficit was the preponderance of colder-than-average nights,
with the all-month anomaly (on min) of –0.7degC, against the 24hr maximum
anomaly of +0.6degC.
> Of
more significance, it was the first August locally since 1998 with the
mean-monthly temperature around, or just below average (1971-2000) value.
> As
an aside, one of the most notable features of the month just gone was the high
number of occasions when the sky was notably clear of pollution and visibility
'good' to 'excellent'; this presumably betraying a high incidence of polar
air-mass intrusions, rather than continental or sub-tropical.
>
Running 12 month temperature anomaly: +0.8 degC (down from +0.9degC last)
RAINFALL:
> As
often happens in this late summer month, much of the rainfall was concentrated
on just a few high-yield events:
> 7
out of the last 10 Augusts had rainfall more than 10% above the eLTA
(1971-2000).
>Running
12 month rainfall anomaly: 79% (was 80% end last month)
[SEASONAL
NOTES]
MnTx MnTn Mn24 HiTx LoTn TotRR
JUNE: 22.2 12.0 17.1 31.8 3.5 29.9
[+2.1] [+1.4][+1.8] [54%]
JULY: 22.8 13.3 18.1 50.3
[+0.2] [+0.6][+0.5] [112%]
AUGUST: 22.5 11.8 17.1 61.2
[+0.6] [-0.7][-0.1] [113%]
OVERALL: 22.5 12.4 17.4 141.4
[+1.0] [+0.5][+0.7] [92%]
TEMPERATURE:
>
The warmth of the summer was concentrated in June, with the 'high-summer'
months rather indifferent.
RAINFALL:
> Two
out of the three summer months had above average rainfall.
Martin.