Summary for February 2004

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HEADLINE: DRY OVERALL: WINDY/VERY MILD START; QUIET MID-MONTH, COLD END

(last updated: 29/1600 November)

Location: Tawfield/Wooden Hill area of SW Bracknell, Berkshire, UK

Altitude 80 m (other location details see signature file appended)

(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):... 14.7(04)

Highest 24hr maximum (date):.. 14.7(04)

Lowest night minimum (date):... -04.4(27)

Lowest 24hr minimum (date): ... -04.4(27)

Lowest overnight grass minimum (date):... -05.5(27)

[ number of days grass minimum < 0degC: ... 10 ]

[ Lowest day maximum (date):... 02.6(28)]

[ Highest night minimum (date):... 11.7(05)]

A. Mean Day (09-18Z) maximum: ... 07.9

A. Mean Night (18-09Z) minimum: ... 03.5

A. Mean of Day Max & Night min: ... 05.7

B. Mean 24hr maximum:... 08.0

B. Mean 24hr minimum:... 03.2

B. Mean of 24hr max & min:... 05.6 (+1.3 eLTA of 4.3/CORRECTED FIGURE)

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

Nr of days minimum at 09UTC <0.0degC:09[dates: 09,21,23-29]

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:

28th: day max. (2.6) lowest of the three winter months;

Mean (24hr) temperature for 1st to 14th: 8.5degC (+4.5degC anomaly*)

Mean (24hr) temperature for 15th to 29th: 2.9degC (-1.2degC anomaly*)

(* using the "whole-month" average)

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PRECIPITATION (PPN/mm)

Total rainfall/melted snow etc:... 027.7 (63% of eLTA)

Highest 24hr total:............... 07.4(01)

No. days PPN total >= 0.2:12

No. days PPN total >= 1.0:07

No. days PPN total >=10.0:00

No. days PPN total >=25.0:00

(Notes relating to precipitation & allied observations:

1st: r(slight) from 16Z, r(R) 1615Z-1720Z; 1st/2nd (overnight): dr(slight), ocnl r; 2nd: idr(slight) much of morning & early afternoon; 2nd/3rd (overnight): ocnl light r; 3rd: r(slight)/r evening, then ocnl slight dr overnight 3rd/4th; 5th: ocnl r early hours; 5th: ir(slight),ocnl r afternoon; 5th/6th: ocnl r overnight; 6th: r(slight)/r 09-13Z, slight dr 13-15Z; 6th: further showers evening; 7th: light pr ~1230/1240Z; 7th/8th: ocnl r; 11th/12th: light rain overnight; 14th: ir(slight) towards end of night, csd by 0830Z; 14th: r(slight) began ~1745Z csd ~ 19Z; 15th: light rain showers ~10Z & 13Z to 1430Z; 17th: ir(slight) from ~10Z, r(slight)/r ~12Z to ~1430Z, r(slight) at 18Z; 18th: pr(slight) ~18Z, r(slight) 21Z-22Z; 22nd: light rain shower ~1245Z; 24th: r(slight) from ~1245Z, csd by 21Z; 25th: light fall snow grains (sh) circa 05Z; 27th: very light snow 0730-0810Z - no accumulation; 28th: light fall snow grains (sh) 06-0840Z also 1415 to 1615Z, with temporary moderate (reduced vis) ~1420Z; 29th: s(v. light) 0800-0805Z - see details below; 29th: light shower snow/snow-pellets mixed 0920Z to 10Z: s(slight) ~1115Z: phs(slight/several) 1515-1615Z, no accumulation from any of these events.

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OTHER TOTALS

Number of days thunder heard: (dates).. 00

Number of days hail < 0.5cm diameter:.. 00

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

Number of days snow/rain & snow:....... 04

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 February, 2004

2nd/3rd (overnight): ocnl F6, temporarily F7; 3rd: remaining windy (F5-6/ocnl F7) during day; 8th: RH<<60% 09-18Z; 19th: a glorious day, b/bc much of time with RH<60%; 22nd: RH<<60% at 18Z: strong, drying winds past three days, with drying of topsoil;

29th:- Around 0800Z (Sunday/29th), for about 5 mins, individual flakes,

averaging around 8mm (dia), falling slowly in light air from what

appeared to be a clump of unstable Ac passing overhead (from the NNE) -

but of no great depth; it is always difficult for a ground observer to

estimate cloud depth at medium levels (perhaps impossible), but watching

the cloud arrive, and depart, I couldn't put it much more than 5000ft

(1500m) deep, and that may be over-stating things. The outside air

temp= - 0.5degC, RH ~90%. The separation between flakes was several

*metres*, and they appeared to be individual elements, NOT aggregates.

Indeed, at the start of the event, I thought a bird had lost a feather

or two, because some of them were up to 15mm diameter.

... 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 08.5 11.4 06.8 03.9 08.5 11.0 06.8 07.4 -

02 09.7 12.3 09.1 00.6 11.0 13.1 tr 00.2 A

03 10.9 13.3 10.4 00.2 13.3 14.4 tr 03.0 B

04 11.6 13.7 11.1 03.0 12.6 14.7 tr 00.3

05 11.7 13.2 (10.5) 00.3 10.6 13.0 01.5 01.9 C

06 09.7 10.9 08.9 00.4 07.7 10.4 05.8 07.2

07 05.1 08.2 03.6 01.4 06.0 08.9 00.2 00.6

08 03.7 06.3 02.1 00.4 04.5 08.2 - -

09 -03.1 04.4 -05.0 - -01.9 04.5 - -

10 00.0 03.1 -02.9 - 03.2 07.5 - -

11 05.6 08.3 04.5 - 08.3 11.9 - 00.1 D

12 07.3 11.0 06.2 00.1 07.9 11.4 - -

13 07.1 09.9 06.7 - 07.3 09.4 tr 00.8

14 06.3 08.0 06.1 00.8 06.6 08.6 tr 01.0

15 05.2 07.0 04.1 01.0 06.1 08.7 00.2 00.2

16 04.3 07.8 01.9 - 05.5 07.9 - -

17 03.7 06.1 01.2 - 05.1 06.9 02.7 02.7

18 03.2 06.2 02.4 tr 04.1 07.5 tr tr

19 02.7 06.5 01.2 tr 04.0 06.6 - -

20 00.9 04.1 00.1 - 01.5 03.1 - -

21 -00.9 02.5 -03.0 - 02.1 06.0 - tr EF

22 03.9 04.6 03.0 tr 03.2 06.0 tr tr

23 -00.8 03.0 -02.2 - 00.7 04.9 - -

24 -02.3 02.9 -04.1 - 01.1 06.7 02.0 02.3

25 -00.3 05.2 -02.1 00.3 00.6 03.0 - -

26 -04.2 01.2 -05.3 - -01.7 03.1 - tr

27 -04.4 01.7 -05.5 tr 01.0 04.2 - tr

28 -02.5 02.2 -04.0 tr 01.4 02.6 tr tr

29 -01.6 02.4 -03.5 tr 00.5 04.8 tr tr

Remarks:

A. 2nd: night max (12.3),(also 24hr max for 1st), occurred 02/09Z

B. 3rd: night max (13.3),(also 24hr max for 2nd), occurred 03/09Z

C. 5th: grass min (10.5) possible error due stuck index.

D. 11th:night max (8.3),(also 24hr max for 10th), occurred 11/09Z

E. 21st (rainday): few spots pr ~ 22/0845Z;

F. 21st: day min (2.1) (also the 24hr min), occurred 21/09Z

--------------- WINTER SUMMARY (DEC/JAN/FEB) -------------

Total precipitation: 181.0 mm ( 101 % of eLTA 1971-2000)

[ NB: running 12-month total PPN: 603.5 mm (89 % of eLTA); taken with the fairly high evaporation rate in recent weeks, I'm not as sanguine as the EA about the availability of ground water. ]

Total days of snow/rain and snow falling: 07 (but several of the 'grains' or 'odd-flakes' variety)

Total days of snow lying at 09Z, covering >50% of ground: 02 (from the 'thunder-snow' event of the 28th January)

Mean (24hr) maximum: 07.9 degC (+0.7 eLTA)

Mean (24hr) minimum: 02.8 degC (+0.8 eLTA)

Mean temperature (based on the 24hr min & max): 05.3 degC

(anomaly +00.7 of eLTA)

February experienced both the highest & lowest temperatures for the winter (14.7degC/4th Feb and -4.4degC/27th Feb).

For other data, see the web site.