Summary for March 2005

======================

HEADLINE: COLD/DRY FIRST THIRD; WARMER MIDMONTH ON. RAIN RETURNS 21ST ON

(last updated: 01/0900 APRIL)

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):... 19.3(19)

Highest 24hr maximum (date):.. 19.3(19)

Lowest night minimum (date):... -04.1(04)

Lowest 24hr minimum (date):... –04.1(04)

Lowest overnight grass minimum (date):... –06.5(04)

[ number of days grass minimum < 0degC: ... 09 ]

[ Lowest day maximum (date):... 03.2(02)]

[ Highest night minimum (date):... 11.7(22)]

A. Mean Day (09-18Z) maximum: ... 11.0

A. Mean Night (18-09Z) minimum: ... 04.5

A. Mean of Day Max & Night min: ... 07.7

B. Mean 24hr maximum:... 11.0

B. Mean 24hr minimum:... 04.1

B. Mean of 24hr max & min:... 07.5 [+0.8 anomaly on eLTA of 6.7degC]

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

Nr of days minimum at 09UTC <0.0degC:07[dates: 01,03-07,13]

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)

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PRECIPITATION (PPN/mm)

Total rainfall/melted snow etc:... 48.4 [93% of eLTA of 52mm]

Highest 24hr total:............... 19.5(29)

No. days PPN total >= 0.2:12

No. days PPN total >= 1.0:09

No. days PPN total >=10.0:01

No. days PPN total >=25.0:00

(Notes relating to precipitation & allied observations:

1st: light s/rs through night 28th Feb/1st Mar: shallow/patchy cover by 09Z – not sufficient to credit 'snow-lying'; depth over grass <0.5cm, 'dusting' elsewhere. All this PPN added to *February* total; ir(slight) from ~11Z, becoming continuous early afternoon, with r/R from mid-afternoon, dying out early evening;

2nd: irs(very light) at 09Z, and at times through day (rain early afternoon); more definite 'snow' late afternoon, but no cover; further rs/s (mainly light) until ~2030Z: patchy/irregular cover grass, icy elsewhere;

3rd: very light ps ~07Z .. a few flakes only; very light ps early PM;

4th: slight snow began ~0702Z, then continuous (ocnl mod) to 0845, whence turning to rain/snow/ice pellets mixed; all ceased by 0920Z; pr circa 1030Z; pr/h/q 1315-1355Z (small hail – small fall only amongst sharp downpour);

5th: prs/s (all very light) from ~ midday; dr(slight) evening;

6th: s/sh(snow/snow grains – very light) early hours;

10th: ir(very light) from ~0810Z, csd by 10Z;

11th: r(slight) 2040Z-~22Z;

12th: very light pr ~1230Z;

13th: very light pr (Sc mam) ~11Z;

15th: id(very slight) ~ 1030Z;

16th: dr/r(slight) from ~ 1615Z, csd by 1930Z

21st/22nd: r(slight), ocnl r from ~ 21/20Z until 22/1030Z;

22nd: pr(mainly slight) from ~22/1625Z through to early evening;

23rd: ir(slight) ~07Z;

24th: ocnl r(R) 01-07Z;

27th: v. light d ~0630Z;

29th: idr(slight) from ~0930Z: bec. r(slight)/r through afternoon, evening & overnight 29th/30th;

30th: further idr(slight) from 09Z, slowly dying out through morning; dr(slight/moderate) from ~17Z, dying out through evening;

31st: ocnl drizzle 06-0815Z; ocnl d(slight) PM; pr late afternoon;

31st/1st April: id(slight) overnight: trace by 01/09Z Apr.)

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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:....... 06

Number of days snow lying at 09UTC:.... 01

Deepest snow cover (date,s):........... 01(04)

Number of days fog (visibility < 1km @ 09UTC).. 01

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Additional comments on the weather in March, 2005

1st: although snow-lying over grass – this patchy & taken overall, not a day with 'snow-lying' at 09Z;

3rd: snow over grass (patchy/<0.5cm) not really representative of general conditions;

4th: snow over grass 0.5-1cm; over hard surfaces average 1cm; all snow gone by midday (melting due rising temperatures & rainwash);

6th: the 14th consecutive day with snow (or variants) falling;

19th: m > f ~ 0630Z, never below 200m: cleared >= 1km by 0915Z

20th: thick haze (surface & elevated) much of day;

23rd:(rainday) – wettest 24hr period in 2005 (so far) with 9.0mm, actually falling in 6hr period 24/01-07Z; wettest 24hr rain-day since 27th December last.

30th: m > f circa 30/1715Z, assw thick drizzle;

31st: period f (600-900m) until ~08Z;

... 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 00.5 02.0 -00.1 00.6 01.8 05.6 06.9 07.3 -

02 00.6 03.2 -00.5 00.4 00.9 03.2 00.2 01.3

03 -01.6 02.7 -03.0 01.1 00.0 03.4 tr 01.6

04 -04.1 01.7 -06.5 01.6 -00.1 07.2 01.1 01.1 A

05 00.4 04.6 -02.0 - 02.1 06.0 tr 00.1

06 -01.4 03.6 -03.2 tr 00.4 04.2 - -

07 -01.6 03.0 -04.0 - 01.5 07.0 - - B

08 04.4 05.9 03.7 - 05.0 07.6 - -

09 04.4 06.3 03.7 - 04.8 08.2 - tr

10 04.1 06.8 03.4 tr 04.6 08.0 tr tr

11 03.5 07.5 00.0 - 07.5 09.8 - 00.4 C

12 02.2 07.9 00.0 00.4 03.8 08.1 tr tr

13 -00.8 06.4 -03.0 - 02.1 06.9 tr tr

14 00.4 05.6 -03.0 - 03.3 09.7 - - D

15 03.9 07.6 01.2 - 07.6 11.5 tr tr E

16 10.5 11.5 09.1 - 11.4 16.9 00.2 00.2 F

17 10.7 12.1 09.7 tr 12.1 17.7 - - G

18 08.8 14.8 08.0 - 10.3 18.1 - -

19 04.9 16.3 01.8 - 07.6 19.3 - -

20 09.0 18.0 07.8 - 11.0 14.3 - -

21 06.3 12.1 04.1 - 09.7 15.6 - 01.5 H

22 11.7 14.2 11.2 01.5 11.5 14.4 03.1 03.2

23 08.6 11.8 07.4 00.1 11.7 16.3 - 09.0

24 10.2 14.4 09.5 09.0 11.5 15.7 - -

25 08.7 13.3 07.2 - 11.7 14.5 - -

26 03.3 13.9 01.1 - 09.7 16.1 - tr

27 07.9 12.3 07.1 tr 08.5 11.0 - -

28 04.4 10.0 01.7 - 08.5 14.6 - -

29 05.8 13.5 03.3 - 07.3 08.5 06.2 19.5 I

30 07.5 08.9 07.1 13.3 08.9 10.5 00.4 02.7 J

31 07.9 10.2 07.9 02.3 08.6 10.5 00.5 00.5

Remarks:

A. day min.(-0.1), also 24hr min for 5th, occurred 04/0900Z

B. day min.(1.5), also 24hr min for 8th, occurred 07/0900Z

C. night max.(7.5) occurred 11/0900Z

D. day min.(3.3) was the 24hr min for 15th, and occurred 14/0900Z

E. day min.(7.6), also 24hr min for 16th, occurred 15/0900Z

F. night max.(11.5) occurred 16/0900Z

G. night max.(12.1) occurred 17/0900Z

H. day min.(9.7), also 24hr min for 22nd, occurred 21/0900Z

I. day min.(7.3), also 24hr min for 30th, occurred 29/0900Z

J. night max.(8.9), also 24hr max for 29th, occurred 30/0900Z

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

maximum temperature >= 21degC (70degF) = 00

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

NOTES RE: 'WINTER-HALF' RAINFALL USING THE EASTHAMPSTEAD PARK / TAWFIELD COMPOSITE RECORD [ 1971/72 – 2004/05: ANOMALIES BASED ON 1971/72 – 2000/01 30 YEAR PERIOD. ]

[ 'Winter-half' covers October to March ]

[DRIEST: <= 300 mm]

RANK AMOUNT PERIOD LTA(71-00)

1. 163mm 1975-76 45%

2. 188mm 1991-92 52%

3. 200mm 1972-73 55%

4. 252mm 1988-89 69%

5. 268mm 1996-97 74%

6. 287mm 1990-91 79%

(7. 313/300mm 2004-05 83%) <==

[WETTEST: >=450 mm]

1. 702mm 2000-01 193%

2. 552/530mm 2002-03 146%

3. 534mm 1994-95 147%

4. 516mm 1976-77 142%

5. 483mm 1974-75 133%

Our dry spell comes within 5 years of the two wettest spells in the last 34 years.

Martin.