Summary
for August 2004
=======================
HEADLINE:
WARM OVERALL: ABOVE AVERAGE (BUT IRREGULAR) RAINFALL.
(last
updated: 29/1600 November)
[
Summer summary at the foot of this sheet. ]
********************************************************************
NOTE: A
BREAK IN OBSERVATIONS 9TH-11TH AUGUST: LAST OB 09/0900Z THEN RETURN 11/1800Z:
INTERVENING DATA HAVE BEEN ESTIMATED, WITH HELP FROM DAVE LLOYD.
********************************************************************
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):... 29.9(08)
Highest
24hr maximum (date):.. 29.9(08)
Lowest
night minimum (date):... 09.2(31)
Lowest
24hr minimum (date):... 09.2(31)
Lowest
overnight grass minimum (date):... 07.6(28)
[
number of days grass minimum < 0degC: ... 00 ]
[
Lowest day maximum (date):... 18.2(29)]
[
Highest night minimum (date):... 19.8(09)]
A. Mean
Day (09-18Z) maximum: ... 23.4
A. Mean
Night (18-09Z) minimum: ... 14.2
A. Mean
of Day Max & Night min: ... 18.8
B. Mean
24hr maximum:... 23.4
B. Mean
24hr minimum:... 14.2
B. Mean
of 24hr max & min:... 18.8 [+1.6 anomaly on eLTA of 17.2degC/AMENDED]
(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:24
Nr of
days maximum at 09UTC >=25degC:09
Nr of
days maximum at 09UTC >=30degC:00
(Notes
relating to temperature & allied observations:
none)
=================================
PRECIPITATION
(PPN/mm)
Total
rainfall/melted snow etc:... 67.1 [124%
of eLTA of 54mm]
Highest
24hr total:............... 16.1(09)
No.
days PPN total >= 0.2:17
No.
days PPN total >= 1.0:12
No.
days PPN total >=10.0:02
No.
days PPN total >=25.0:00
(Notes
relating to precipitation & allied observations:
2nd:
ir(very slight) from Ac cast. 1650-1715Z;
3rd:
ocnl ir/pr (slight) ~0630-0800Z: Ac cast; tl(slight)r(slight) 1425 - 1545Z,
ir(slight) from about 1730Z, dying out soon after 18Z;
5th:
t(1425Z): r(slight) ocnl r(R) [with ts(slight ocnl moderate)] (see below)
1440Z-1640Z; short fall of hail (>5mm dia) ~1512Z for less than one minute:
total rainfall (& small element melted hail) = 6.5mm;
8th:
ir(few drops only) ~1515Z;
8th/9th:
r(slight)/r overnight, r(slight) 09/0620-0815Z;
9th:
dr(slight) 09-11Z; further rain PM: a 'wet' night 9th/10th - rain dying out
before late morning 10th;
11th:
local showers 08Z-10Z; pr(slight)/idr(slight) 1445Z-1530Z;
11th/12th:
r(slight)/r ~11/21Z-~12/01Z;
12th:
pr(slight) afternoon [ pr/R vicinity ];
13th:
pr(slight/very) afternoon;
15th:
ir(slight) 1045-11Z;
15th/16th:
ir(slight) overnight;
16th:
r(slight)/r 1335-1425Z, ir(slight) ~15Z;
17th:
r(slight)/r from ~2030Z, further r(slight)/r ~ 23Z (~2mm)
18th:
r(R) 0820-0905Z (~9mm), ocnl pr(slight) during day,
tl(slight/moderate)r(slight/moderate, ocnl heavy) 1520-1550Z, then r/r(slight)
ceasing by ~1615Z (~3mm);
18th/19th:
r(slight)/r ~23Z-01Z;
19th:
pr(slight)/pr 0935-0945Z, other pr(slight) thru' day & early evening; 20th: tl(slight)r(slight) or pr(slight)
1620-1745Z; r(slight)/r 1825-1930Z & ~ 23Z;
22nd/23rd:
r(R) ~22/21Z-~23/05Z;
23rd:
pr(slight)/pr 0830-0855Z; further pr(slight)/pr during day;
24th:
ocnl r early hours; r(slight) 0845Z to 0905Z, the ocnl pr through day;
25th:
id(slight) ~07Z; r(slight), ocnl r 1630Z-1815Z;
27th:
r(slight)/r from ~03Z until ~1215Z;
29th:
idr(slight) ~0830Z; r(slight) 1100-1115Z; pr(slight), isol pr afternoon until
about 1615Z;
30th:
pr(slight), short burst moderate, from 10Z to ~13Z;
=================================
OTHER
TOTALS
Number
of days thunder heard: (dates).. 04(03,05,18,20)[incomplete record]
Number
of days hail < 0.5cm diameter:.. 00
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, 2004
3rd:
tl(slight)
1425Z-1545Z: low-frequency, distant (CC?) thunder only (severe weather in
vicinity, but we were in the weaker phase of a line of multi-cells moving
slowly north);
5th:
1425Z:
t (thunder heard).
1440Z:
tl(slight)r(slight).
1500-1512Z:
tl(slight)r(slight)q (Bft 5 or 6), with ~1512Z hail (dia. >5mm): rain
moderate or heavy for a time during this period.
1518Z:
tl(moderate)rain(slight) with mostly CC activity, but CG close-by.
1527-1552Z:
tl(moderate)rain(moderate) with ocnl 'sharp' CG nearby, the rain easing to
slight again by about 1550Z: thunder frequency roughly 4 or 5 per minute, but
CG "close-by" strokes just one per 3 minutes or so.
1615Z:
tl(slight)r(moderate) - thunder receding.
1640Z:
tl(slight), precipitation now ceased.
1650Z:
thunderstorm ceased.
18th:
1515Z:
t (thunder heard).
1520Z:
tl(slight)r(slight).
1525Z:
tlr
1535Z:
tlr(R)
1540Z:
tl(slight)r
1550Z:
r(slight)/r (ts ceased by 10min rule)
20th:
1235Z-1320Z
& 1442Z-1500Z: adjacent t/tl(slight), but NO precipitation recorded (local
moderate ts & heavy downpours apparently).
1620Z:
t, then 1625Z tl(slight)r(slight) to 1720Z, when thunder ceased (rain, very
light/not recordable, continued to 1745Z)
...
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 15.9
26.8 14.4 -
22.2 26.8 -
-
02 14.9
25.0 14.1 -
21.3 28.2 tr
tr
03 17.9
25.5 16.8 tr
20.7 28.0 tr
tr
04 14.4
23.0 12.4 tr
22.1 29.6 -
-
05 17.9
27.5 16.8 -
18.7 28.2 06.5
06.5
06 14.3
19.9 13.4 -
19.7 27.9 -
-
07 13.5
24.8 12.4 -
21.2 29.2 -
-
08 17.3
27.4 16.4 -
24.6 29.9 tr
00.9
09 19.8
26.3 19.1 00.9
20.7 (22.7)(05.4) (16.1)
-------
see note above re: break in observations -------
10
(16.6) xx.x xx.x (10.7) xx.x
25.4 (00.1) (00.1)
11 15.9
xx.x 14.9 (tr )
xx.x (22.4)(00.2) (02.0)
12 16.7
21.2 16.2 01.8
19.1 23.8 tr
tr
13 14.4
20.4 13.5 -
17.3 23.2 tr
tr
14 14.7
20.5 13.2 -
17.9 24.7 -
-
15 14.0
22.4 12.6 -
19.8 23.5 tr
tr
16 15.2
20.5 14.4 tr
18.2 21.2 01.2
01.2
17 14.7
18.4 13.9 -
18.4 23.4 -
10.9 A
18 16.2
20.8 15.2 10.9
17.0 22.5 03.6
06.5
19 14.3
17.8 13.6 02.9
16.7 22.0 00.5
00.5
20 14.0
19.4 13.2 tr
17.3 21.0 tr
03.2
21 10.3
18.3 09.3 03.2
15.0 20.0 -
-
22 11.7
18.1 11.1 -
16.5 21.5 -
07.9
23 13.4
18.9 12.8 07.9
16.3 20.5 00.7
01.7
24 14.5
19.0 13.5 01.0
17.0 20.4 02.5
02.5
25 12.8
17.9 11.3 tr
15.8 21.1 02.4
02.5
26 11.9
16.7 10.9 00.1
16.8 21.5 -
03.2 BC
27 13.7
18.7 12.7 03.2
16.3 21.0 00.5
00.5
28 09.3
19.4 07.6 -
15.2 19.9 -
tr
29 11.3
17.5 10.4 tr
14.6 18.2 00.3
00.3
30 10.8
16.3 09.7 -
15.5 18.9 00.6
00.6
31 09.2
17.0 07.7 -
14.0 20.2 -
-
Remarks:
A.
night max (18.4) occurred at 17/09Z
B.
night max (16.7) occurred at 26/09Z
C. PPN
25/18Z to 26/09Z combination of residual rain & heavy dewfall
Number
of occasions (24hr periods) THIS YEAR (2004)
maximum
temperature >= 21degC (70degF) = 71
minimum
temperature >= 16degC (61degF) = 12
Summer
summary (June to August)
MnTx MnTn Mn24 HiTx LoTn TotRR
JUNE: 22.1 11.8 16.9 29.9 5.8 25.9
+2.0 +1.2 +1.6
47%
JULY: 22.4 12.3 17.3 28.8 8.5 39.0
-0.2 -0.4 -0.3
87%
AUGUST: 23.4 14.2 18.8 29.9 9.2 67.1
+1.5 +1.7 +1.6 124%
OVERALL 132.0
+1.0 86%
Some
highlights:
(a):
Despite national concerns re: rainfall, this August just gone has been the
wettest only since 2002 (70.4mm/TF data); even if you add in, say, 30mm to
account for the fact that we missed out on a heavy shower/thunderstorm that
affected central Bracknell (5th), there would by this crude (& very
generous) adjustment still be at least three wetter Augusts in the last 33
years in the area.
(b):
For the summer overall, the anomaly was 86% eLTA. June was notably dry, July's
rain was rather fitful (and below average), and even in August, until the last
third of that month, we were running around 75-80% of monthly average. Summer
2002 was *much* wetter, with 223mm (145%eLTA).
(c):
Not only has rainfall this summer (2004) NOT been a feature hereabouts, but
when investigating the split for August (the so-called 'wet' month), between
'day' (09-18Z) and 'night' (18-09Z), the difference is thus: 63% of the rain
came between the hours of 7pm and 10am the next day, with the remainder, 37%
10am - 7pm. Some of these latter were 'torrential' downpours, but that meant of
course that much of the day was dry, and often sunny!
(d): As
to temperatures, the overall mean showed an anomaly of +1.0degC from eLTA. June
and August were greater than +1.5degC anomaly.
(e): As
noted earlier, there was an extended period of day-time temperatures >=
21degC, from 13th July to the 20th August - well over a month. There were 12
nights when the temperature failed to fall below 16degC.
In
addition, for the summer overall, there were 64 days with maxima >=21 (69%),
and 21 days with maxima >=25degC (23%). In these terms, quite a decent
summer!
Martin.