Summary
for April 2006
======================
HEADLINE:
MILD OVERALL BUT CHILLY FIRST THIRD. VERY DRY UNTIL LAST DAY
(last
updated: 01/1400 MAY)
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; )
=================================
TEMPERATURES
ETC.
Highest
day maximum (date):... 18.4(22)
Highest
24hr maximum (date):.. 18.4(22)
Lowest
night minimum (date):...-00.7(05)
Lowest
24hr minimum (date):...-00.7(05)
Lowest
overnight grass minimum (date):... -03.7(06)
[
number of days grass minimum < 0degC: ... 06 ]
[
Lowest day maximum (date):... 08.3(11)]
[
Highest night minimum (date):... 09.9(27)]
A. Mean
Day (09-18Z) maximum: ... 13.4
A. Mean
Night (18-09Z) minimum: ... 05.6
A. Mean
of Day Max & Night min: ... 09.5
B. Mean
24hr maximum:... 13.4
B. Mean
24hr minimum:... 05.6
B. Mean
of 24hr max & min:... 09.5 [+0.7 anomaly on eLTA of 08.8degC]
(data
below relate to 24 hr day beginning 09Z on date given)
Nr of
days minimum at 09UTC <0.0degC:02[dates: 05-06]
Nr of
days maximum at 09UTC >=21degC:00
Nr of
days maximum at 09UTC >=25degC:00
Nr of
days maximum at 09UTC >=30degC:00
(Notes
relating to temperature & allied observations:
none)
=================================
PRECIPITATION
(PPN/mm)
Total
rainfall/melted snow etc:... 40.8 [78%
of eLTA of 52 mm]
Highest
24hr total:............... 11.9(30)
No.
days PPN total >= 0.2:13
No.
days PPN total >= 1.0:11
No.
days PPN total >=10.0:01
No.
days PPN total >=25.0:00
(Notes
relating to precipitation & allied observations:
31st
March / 1st April: rain early night,
with pr(R) 01/0630-0700Z .. all credited to March;
1st:
pr(slight/moderate) ~1500/1510Z;
1st/2nd:
r/R (travelling wave) ~2300 to ~0230Z;
2nd:
pr(R) from ~10Z to ~15Z, with pR/h(<5mm dia.) ~1350Z;
3rd:
pr(slight/few drops) 0830Z-0930Z;
7th:
ir/pr(slight) early afternoon;
8th:
ocnl r(slight)(r) 02-06Z; r(R) ~2000/2015Z;
9th:
pr(slight ocnl moderate) from 1325Z until evening/overnight, as r(slight)/r,
possibly with sleet phase as it died out by 10/04Z;
11th:
r(slight), ocnl r from 1150Z, with periods r(R) until 18Z, then ir(slight)
dying out by 1830Z;
14th:
idr(slight) ~08Z; idr(slight), ocnl dr (poor vis.) until ~ midday;
14th/15th:
id(very light) and/or w overnight = measured trace;
16th:
r(slight), ocnl r 1425-1510Z; r(slight), tempo. r 1405-1510Z, ir(slight) then
to ~1630Z;
18th:
r(slight) from ~1620Z to ~1730Z;
20th:
dr(slight), ocnl r, from ~0630Z through morning: pr(slight) PM, becoming dry by
~1530Z;
20th/21st:
id/r(mainly slight) evening & early night;
23rd:
r(slight) from 0445Z, ocnl r 09-12Z, dying out by 15Z;
23rd/24th:
idr(slight), ocnl r(slight)/r evening & overnight;
24th:
id(very light) until ~12Z;
25th:
r(slight), isol r, 0950-11Z; id(slight) ~1635/40Z;
28th:
pr(few droplets) ~1115Z;
30th:
r(slight) from ~0655Z, ocnl r from 09Z, csd by 1015Z. pr/r(slight) ~1630/40Z;
30th/1st
May: r(R) from late evening 30th to 0730Z (slight for last hour or so), then
rapid post-frontal clearance; the rainfall for this period (12mm / ~9hr)
represented nearly 30% of the full-month total.
=================================
OTHER
TOTALS
Number
of days thunder heard: (dates).. 00
Number
of days hail < 0.5cm diameter:.. 01
Number
of days hail >=0.5cm diameter:.. 00
Number
of days snow/rain & snow:....... 00 (see note below)
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 April, 2006
2nd:
small hail amongst heavy rain ~1350Z – hail element small;
[thunder]
Nil.
[snow]
10th:
there may have been a short 'sleet' phase as overnight PPN died away but as I
didn't observe it, it is not recorded above.
...
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 08.2
12.4 06.8 02.8
09.4 13.8 tr
03.6 -
02 05.2
11.5 03.2 03.6
08.7 12.6 03.1
03.1
03 05.2
11.1 03.1 tr
07.8 12.2 tr
tr
04 00.6
09.9 -02.4 - 04.8
08.9 - -
05
-00.7 07.2 -03.4 - 04.0 10.5 -
-
06
-00.1 04.6 -03.7 -
06.2 12.0 -
-
07 03.4
09.8 01.0 -
08.7 12.2 tr
01.1
08 05.4
09.2 03.4 01.1
07.2 11.4 -
tr
09 01.0
09.6 -01.2 tr 05.1
11.9 02.6 07.0
A
10 01.0
05.1 -00.9 04.4 04.4
10.0 - -
11 01.0
08.1 -02.3 - 05.7
08.3 04.1 04.3
12 03.3
08.4 01.2 00.2
08.4 13.1 -
- BC
13 08.8
11.5 07.4 -
11.5 14.3 -
tr
14 06.7
12.4 03.8 tr
10.3 14.8 02.5
02.5
15 07.5
14.3 06.4 tr
09.5 14.9 -
-
16 08.2
12.6 04.7 -
11.6 16.4 01.5
01.5
17 05.0
12.2 01.5 -
10.5 14.8 -
-
18 04.8
12.8 04.0 -
09.9 14.5 00.1
00.1
19 07.2
11.3 05.9 -
10.9 14.0 -
00.2
20 09.8
12.6 09.3 00.2
10.7 12.8 01.1
01.4
21 08.6
11.6 07.9 00.3
11.4 17.3 -
-
22 07.6
16.1 07.5 -
08.9 18.4 -
01.2
23 08.2 16.8 07.3 01.2
09.7 12.6 01.2
02.0
24 09.3
12.5 09.2 00.8
09.7 14.8 tr
tr
25 07.6
14.1 04.7 -
11.1 14.4 00.7
00.7
26 07.4
14.3 04.9 -
11.9 16.0 -
-
27 09.9
14.4 08.3 -
13.5 16.4 -
-
28 05.2
14.2 03.1 -
10.7 14.6 tr
tr
29 07.3
12.7 07.0 -
10.1 13.7 -
00.1
30 04.9
12.0 03.3 00.1
06.7 11.6 00.1
12.0 D
Readings
taken at 0900 and 1800 UTC. Where the NIGHT maximum or DAY minimum are
significantly different from 24hr values, this will be noted in the listing
against a 'Remarks' letter. There are two mean 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) .. 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.
Remarks:
A.
(Screen cleaned / paintwork re-touched 0900-1200: 'true' maximum temperature
captured just after midday.)
B.
night max.(8.4), also 24hr max. 11th, occurred 12/09Z
C. day
min.(8.4), also 24hr min. 13th, occurred 12/09Z
D. day
min.(6.7), also 24hr min. 1st May, occurred 30/09Z
Number of
occasions (24hr periods) THIS YEAR (2006)
maximum
temperature >= 21degC (70degF) = 00
minimum
temperature >= 16degC (61degF) = 00
Rolling
12 month temperature anomaly: +0.4 (was +0.4 end last month)
Rolling 12
month rainfall anomaly: 85% (was 88% end last month)
Rolling 24
month rainfall anomaly: 83% (was 87% end last month)
[RAINFALL]
The
total rainfall for this station for April 2006 = 40.8mm (78% eLTA 1971-2000).
Until the night of the 30th April / 1st May, this would have been one of the
driest such-named months in a composite record for this location (since 1971);
with the final rainfall, which fell late-evening 30th to 0730Z 1st May, there
is nothing particularly remarkable about the month's total, being well outside
the 'top-10' lowest in the past 35 years.
Dry
Aprils are tabulated below:-
In a
composite record (Easthampstead Park / Tawfield) since 1971, the following are
the 'top-10' driest Aprils in that record:-
<dry
Aprils/1971-2006>
Rank Year Total
1. 1984:
2.9mm
2. 1997: 10.8mm
3. 1976: 11.7mm
4. 1982: 16.0mm
5. 1980
& 1974: 19.8mm
7. 1988: 29.5mm
8. 1995: 30.8mm
9. 1985: 31.5mm
10. 1996: 31.6mm
Total
rainfall this year (2006) so far: 175.6mm (82 % of eLTA). Last year by the same
time, we had had a total of 155.2mm. In the composite record since 1971, the
lowest total for these first four months of the year occurred in 1976 with
69.2mm, followed by 1997 with 101.8mm, so we are some way from any sort of
record.
[TEMPERATURE]
Maximum
temperature achieved: 18.4 (22nd). This
is the lowest April maximum in our short record (7 years): the previous lowest
was 18.8 (29th April, 2000).
From
2002 to 2005, the 21degC 'threshold' has been achieved in April, but not this
year. Previous failures to reach '70degF' occurred in 2000 & 2001, but in
marked contrast to this year, these Aprils were notably (exceptionally for
2000) wet. In 2000, 21degC was not reached until 6th May, and in 2001 we had to
wait until the 10th May.
The
overall mean anomaly +0.7, mean min +0.9, mean max +0.5. This was the first
month since October last year with a positive anomaly >0.5C, though the
anomaly was largely a function of the relatively mild nights for much of the
month, rather than notably warm days.
Martin.