Summary for July 2005

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HEADLINE: COOL/DAMP START. HOT SPELL MID-MONTH: HEAVY RAINFALL FINAL WEEK

(last updated: 01/1400 AUGUST)

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):... 30.6(13)

Highest 24hr maximum (date):.. 30.6(13)

Lowest night minimum (date):... 08.6(05)

Lowest 24hr minimum (date):... 08.6(05)

Lowest overnight grass minimum (date):... 07.4(05)

[ number of days grass minimum < 0degC: ... 00 ]

[ Lowest day maximum (date):... 15.1(27)]

[ Highest night minimum (date):... 16.9(11,14)]

A. Mean Day (09-18Z) maximum: ... 22.7

A. Mean Night (18-09Z) minimum: ... 13.3

A. Mean of Day Max & Night min: ... 18.0

B. Mean 24hr maximum:... 22.8

B. Mean 24hr minimum:... 13.3

B. Mean of 24hr max & min:... 18.1 [+0.5 anomaly on eLTA of 17.6degC]

(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:19

Nr of days maximum at 09UTC >=25degC:08

Nr of days maximum at 09UTC >=30degC:02[dates: 13,14]

(Notes relating to temperature & allied observations:

5th: coldest July day here since 2000;)

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PRECIPITATION (PPN/mm)

Total rainfall/melted snow etc:... 50.3 [112% of eLTA of 45mm]

Highest 24hr total:............... 12.0(24)

No. days PPN total >= 0.2:12

No. days PPN total >= 1.0:10

No. days PPN total >=10.0:01

No. days PPN total >=25.0:00

(Notes relating to precipitation & allied observations:

1st: ir(slight) from 14Z bec r(slight)/r from 1545Z, csd by 17Z;

1st/2nd: ocnl dr(mainly light) overnight, ceased by 06Z;

3rd: dr(slight), ocnl dr or r(slight) 1155Z-1400Z;

4th: ir(v.slight) ~ 1030Z; ph(slight/2-5mm dia.)r(slight) ~1350Z; tl(slight)r(slight/moderate) 1529-1540Z; pr(slight) else;

5th: ir(slight) 09-14Z, then dr(slight), ocnl r thereafter, dying out early evening;

6th: very light pr early morning;

7th: ir(slight) early until 0630Z & again from ~0845Z until just after midday; pr(slight), ocnl pr thereafter;

8th: ir(very light/few droplets) ~1330Z;

9th: dr(light) 0640-0730Z;

18th: r(very light) 1510-1525Z; r/R 1705-1750Z, then light, csd by 1815Z;

23rd: r(slight) 0755-0815Z; pr(very light) throughout day – no impact;

24th: r(slight), ocnl r from ~04Z, with r(R) from 09Z to 1130Z: dr(slight/moderate) thereafter, ceased abruptly ~13Z (occluded/surface frontal clearance);

24th/25th: r(R) overnight; pr(slight) > dr(slight/moderate) 25/08Z onwards, dying out by 10Z;

26th: r(slight) began 1930Z, continuing evening/overnight (26th/27th), ocnl moderate;

27th: further r(slight)/r, then dr(slight/moderate) ocnl r(slight/moderate) for rest of day & evening;

27th/28th: drizzle/rain, ocnl moderate, overnight – continuing until morning 28th, fizzling out during late morning; pr(very slight) 28th PM;

30th: ir(very light) 05-06Z; pr(light/moderate) from 11Z, with pr/R between 1630 & 1645Z, which contributed the bulk of the 5mm 09-18Z; pr/R early evening, csd by 2030Z;

31st: r/R much of evening -> r(slight)/r early hours 1st to ~01/07Z;

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OTHER TOTALS

Number of days thunder heard: (dates).. 01 (04)

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

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Additional comments on the weather in July, 2005

4th: slight thunderstorm (couple of distant rumbles only) 1529-1540Z, accompanied by slight-moderate rain;

12th: superb clarity of air & blueness of sky

14th: considerable elevated haze

Of the rainfall this month (50.3mm), the bulk (40.1mm/80% of total) fell over a period of 9 days, from the 23rd to the 31st inclusive.

... 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 11.9 19.1 10.7 00.2 17.7 21.0 00.1 00.3 -

02 16.2 19.8 15.9 00.2 19.1 21.2 - -

03 12.3 19.1 11.0 - 16.7 19.7 01.6 01.6

04 10.9 19.3 09.7 - 13.4 17.7 03.6 03.9

05 08.6 15.8 07.4 00.3 14.7 16.9 02.1 02.3

06 12.6 16.3 11.7 00.2 15.9 19.2 - tr

07 12.1 17.1 10.8 tr 14.6 18.9 00.6 00.6

08 10.7 16.5 09.2 - 15.3 19.7 tr tr

09 13.9 19.4 13.7 tr 14.5 21.6 - -

10 12.7 22.2 (11.-) - 22.2 28.9 - - AB

11 16.9 27.6 14.2 - 24.5 27.7 - -

12 14.2 26.2 13.8 - 18.6 27.8 - -

13 13.3 26.5 12.0 - 24.5 30.6 - -

14 16.9 28.7 15.8 - 25.1 30.5 - -

15 15.3 27.9 13.7 - 20.2 28.0 - -

16 12.7 26.0 10.2 - 19.4 24.9 - -

17 11.9 23.4 09.8 - 23.0 28.9 - -

18 14.8 26.4 14.4 - 17.6 25.3 01.5 01.5 C

19 12.1 18.8 10.9 tr 18.0 22.7 - -

20 14.4 20.1 13.3 - 20.1 24.9 - -

21 11.7 22.6 10.5 - 19.7 24.6 - -

22 11.4 23.0 09.6 - 16.4 22.7 tr tr

23 15.2 21.1 13.3 tr 18.6 22.9 tr 03.0

24 15.1 21.9 14.6 03.0 15.6 20.8 05.6 12.0

25 15.2 19.8 14.5 06.4 15.0 16.5 tr tr

26 13.2 16.5 ---- - 16.5 19.1 - 04.3 DE

27 12.4 18.0 12.3 04.3 12.8 15.1 02.1 02.8 F

28 15.1 17.5 15.0 00.7 17.5 24.0 tr tr G

29 13.7 22.3 12.6 - 17.5 21.2 - tr

30 12.2 20.0 11.2 tr 16.5 20.2 05.0 09.2

31 14.1 17.0 13.6 04.2 15.3 20.6 - 08.8

Remarks:

A. grass min. index stuck: estimate based on early reading.

B. night max.(22.2), also 24hr max. for 9th, occurred 10/09Z

C. day min.(17.6) occurred following air-mass change at 18/18Z

D. grass min. index stuck (26th); no estimate possible

E. night max.(16.5), occurred 26/09Z, but also occurred 25/18Z, and was the 24hr max for the 25th

F. day min.(12.8), also 24hr min 28th, occurred 27/09Z

G. night max.(17.5), also 24hr max 27th, occurred 28/09Z

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

maximum temperature >= 21°C (70°F) = 38 (c.f. 47 same time 2004)

minimum temperature >= 16°C (61°F) = 08 (c.f. 05 same time 2004)

TEMPERATURE:

Period 1st – 9th & 24th – 31st, day maxima generally below average, notably so during the first grouping. The notable 'hot' spell 10th – 15th (two days with maxima >30°C), helped to drive the all-month average well above eLTA by the end of the second week, but it drifted downwards again over the recent cyclonic spell. Taking the month as a whole, the 'warmth' showed up as a greater +ve anomaly for the minimum temperatures (+0.6degC), than the

maxima (+0.2degC), again emphasising the 'indifferent' nature of the weather for July 2005.

RAINFALL:

Using a composite Easthampstead Park / Tawfield record (1971 – 2005 / 35years)

1. July 2005 is the wettest month (by total and anomaly) only since April 2005.

2. It is the wettest July since 2002 (87mm)[i.e. for 3 years]

3. In the 35 year series, it ranks (roughly) as the 11th wettest July.

[ The wettest July occurred in 1988, with 107mm ]

Rainfall anomaly this year (so far) = 71% (was 64% end June)

Running 12 month temperature anomaly: +0.9 degC (up from +0.8degC last)

Running 12 month rainfall anomaly: 80% (was 78% end last month)

Martin.