Summary for April, 2005

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HEADLINE:COLD SNAP END FIRST WEEK, THEN UNSETTLED: MILD OVERALL

(last updated: 01/0900 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; ) 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.

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TEMPERATURES ETC.

Highest day maximum (date):... 21.4(30)

Highest 24hr maximum (date):.. 21.4(30)

Lowest night minimum (date):...-01.4(09)

Lowest 24hr minimum (date):...-01.4(09)

Lowest overnight grass minimum (date):...-03.5(09)

[ number of days grass minimum < 0degC: ... 05 ]

[ Lowest day maximum (date):... 06.9(08)]

[ Highest night minimum (date):... 12.9(30)]

A. Mean Day (09-18Z) maximum: ... 14.2

A. Mean Night (18-09Z) minimum: ... 05.8

A. Mean of Day Max & Night min: ... 10.0

B. Mean 24hr maximum:... 14.2 (+1.3)

B. Mean 24hr minimum:... 05.7 (+1.0)

B. Mean of 24hr max & min:... 09.9 [+1.1 anomaly on eLTA of 8.8degC]

(data below relate to 24 hr day beginning 09Z on date given)

Nr of days minimum at 09UTC <0.0degC:01[dates: 09]

Nr of days maximum at 09UTC >=21degC:01

Nr of days maximum at 09UTC >=25degC:00

Nr of days maximum at 09UTC >=30degC:00

(Notes relating to temperature & allied observations:

none)

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PRECIPITATION (PPN/mm)

Total rainfall/melted snow etc:... 57.9 [111% of eLTA of 52mm]

Highest 24hr total:............... 16.2(24)

No. days PPN total >= 0.2:18

No. days PPN total >= 1.0:08

No. days PPN total >=10.0:01

No. days PPN total >=25.0:00

(Notes relating to precipitation & allied observations:

34mm (out of a total of 58mm) fell in period of just four days: 24th-27th; this represents nearly 3/5 of the monthly total.

1st: id(light) overnight 31st March-1 April: credited to March;

4th: r(slight) from 0610Z, ocnl r between 08 & 09Z: idr(mainly slight) from ~09Z, dying out by 1130Z; pr(slight) early evening;

6th: r(slight) from ~0615Z, bec r ~0850Z, then r(slight), ocnl r until ~1230Z;

7th: pr(very light) 0815-0840Z; several pr(slight)/isol pr through day, then ph(slight)r 1705Z (dia. <5mm), soon becoming r, then r(slight);

8th: pr/rs(slight) from about 0630Z – mainly rain; phrs(all slight) ~08Z (snow pellets); rs(slight) by 09Z (s/slight 0915-0935Z), bec r(slight) by 0945Z, csd by 1015Z;

9th: pr(slight) from 1730Z to ~19Z;

12th: very light r ~12Z;

13th: r(slight), ocnl r ~03Z – 0840Z; pr(slight) morning;

14th: ir(slight) early hours; r(slight) 08-0830Z; pr(slight) 1650-1720Z, with short pr(slight)h(slight/<5mm dia.) ~ 1700Z;

15th: ir(slight) during day, mainly PM, dying out early evening;

17th: ir(slight) from 1550Z, bec. continuous ~1730Z, csd for a time evening;

17th/18th: r(slight)/r overnight, csd by 07Z; pr 08-0830Z;

19th: r ~05Z; tl(slight)r 0535-0540Z; pr(slight) much of afternoon, with tl(slight) 1412-1440Z & 1517-1530Z;

23rd: dr(mainly slight) from latter part of night, csd by 13Z; further ir(slight)~16Z;

24th/25th: r(slight)/r from late eve. 24th . . .>

25th: period r/R 0730-0830Z, within continuous rainfall since 24th/late eve: slowly dying out by 25/12Z;

26th: r(slight) from 0830Z to ~1230Z, with periods r/R just after 12Z; further r/R 1930-1950Z, becoming r/r(slight) by 2030Z;

27th: tl(slight)r(slight/moderate) 1228-1250Z, otherwise ocnl pr during afternoon;

27th/28th: idr(very light) overnight & just before 09Z/28th;

28th: r(slight) from ~17Z; ir(slight) evening;

29th/30th: dr(slight) overnight;

30th: r(slight) from medium level unstable cloud early evening;

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OTHER TOTALS

Number of days thunder heard: (dates).. 02 (19,27)

Number of days hail < 0.5cm diameter:.. 03

Number of days hail >=0.5cm diameter:.. 00

Number of days snow/rain & snow:....... 01

Number of days snow lying at 09UTC:.... 00

Deepest snow cover (date,s):........... -

Number of days fog (visibility < 1km @ 09UTC).. 00

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Additional comments on the weather in April, 2005

8th: various sleet/snow events had no effect on surfaces;

15th: fog 0530-0630Z;

19th: tl(slight) 0535-0540Z, single rumble thunder; further thunderstorms (slight) 1412-1440 & 1517-1530Z: very poor affairs;

21st: exceptionally dry air afternoon - <<40%, probably below 30% for a time;

27th: tl(slight)/two or three flashes only 1228-1250Z, but rainfall moderate;

... 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 07.9 10.0 07.5 tr 08.8 15.0 - - -

02 08.2 13.6 05.4 - 11.3 18.6 - -

03 07.3 15.0 04.4 - 13.4 18.4 - 00.6

04 10.0 15.1 07.4 00.6 09.2 12.5 00.2 00.2

05 03.3 11.6 01.7 tr 08.4 12.0 - 00.8

06 06.8 10.0 05.6 00.8 08.7 13.9 01.6 01.6

07 06.1 12.2 05.0 tr 06.7 12.1 08.1 08.2

08 03.8 06.7 03.2 00.1 03.1 06.9 00.8 00.8

09 -01.4 05.2 -03.5 - 05.2 10.7 tr tr AB

10 05.5 10.0 04.2 tr 10.0 15.7 - - C

11 04.3 13.8 01.5 - 10.5 15.9 - -

12 05.4 13.3 03.7 - 10.6 15.1 tr 03.1

13 06.5 14.1 05.2 03.1 08.2 13.2 tr 00.2

14 06.6 11.0 05.4 00.2 08.0 13.1 00.2 00.2

15 02.2 09.4 00.3 - 06.2 09.1 00.4 00.5

16 01.7 08.0 -00.5 00.1 07.3 10.5 - -

17 00.7 09.8 -02.1 - 08.1 13.7 00.4 06.0

18 07.3 10.2 06.8 05.6 09.4 14.2 - 00.4

19 04.5 12.5 01.7 00.4 09.2 14.5 00.1 00.1

20 02.5 10.6 -00.1 - 08.6 11.4 - -

21 03.4 10.6 00.4 - 07.6 16.0 - -

22 02.8 13.8 -00.2 - 11.3 17.2 - 00.7

23 08.4 15.1 07.4 00.7 10.0 13.6 00.9 00.9

24 05.8 12.3 03.2 - 10.3 16.5 - 16.2

25 08.0 15.2 07.9 16.2 08.2 12.2 04.4 04.4

26 07.6 12.4 04.9 tr 11.1 14.6 03.5 08.1 D

27 06.0 13.1 04.0 04.6 09.0 14.9 04.9 04.9

28 09.4 12.5 08.2 tr 12.0 13.9 tr tr

29 10.0 12.6 08.0 tr 12.6 19.3 - tr E F

30 12.9 16.9 06.6 tr 14.7 21.4 - tr

Remarks:

A. 9th: night max.(5.2) occurred 09/09Z

B. 9th: day min.(5.2) occurred 09/09Z was also 24hr min for 10th

C. 10th:night max.(10.0) occurred 10/09Z

D. 26th: night max.(12.4), also 24hr max 25th, occurred early evening of the 25th (temperature at 25/18Z = 12.2)

E. 29th: night max.(12.6) occurred 29/09Z

F. 29th: day min.(12.6), also 24hr min 30th, occurred 29/09Z

Number of occasions (24hr periods) THIS YEAR (2005)

maximum temperature >= 21degC (70degF) = 01

minimum temperature >= 16degC (61degF) = 00

(Summary of spring 2005 so far . . .

Temp anomaly (wrt 71-00): +0.9 [ last yr. +0.5 ]

Year so far:

Temp anomaly: +0.9 (c.f. +0.9 last yr.)

Rainfall total: 74% (c.f. 112% last yr.)

12 month rolling precipitation anomaly: 82% )