Summary for May 2004

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

HEADLINE:UNSETTLED/COOL START. DRY/WARMER BY MID-MONTH: SHOWERY 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):... 24.8(19)

Highest 24hr maximum (date):.. 24.8(19)

 

Lowest night minimum  (date):... 03.4(23)

Lowest 24hr minimum   (date):... 03.4(23)

 

Lowest overnight grass minimum (date):... 02.0(23)

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

 

[ Lowest day maximum  (date):...   11.1(04)]

[ Highest night minimum (date):... 13.8(29)]

 

A. Mean Day (09-18Z) maximum:   ... 18.3

A. Mean Night (18-09Z) minimum: ... 08.6

A. Mean of Day Max & Night min: ... 13.4

 

B. Mean 24hr maximum:... 18.3

B. Mean 24hr minimum:... 08.5

B. Mean of 24hr max & min:... 13.4 (+1.0 on 1971-2000 eLTA of 12.4/CORRECTED FIG.)

 

(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:06

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:... 052.0  (90% of 1971-2000 eLTA)

Highest 24hr total:............... 14.3(03)

No. days PPN total >= 0.2:10

No. days PPN total >= 1.0:10

No. days PPN total >=10.0:02

No. days PPN total >=25.0:00

(Notes relating to precipitation & allied observations:

1st: r(slight) 06-08Z/to April's total; v.light r 09Z-12Z;

3rd: r(slight) 07Z, becmg r 0745-0830Z, then slight: becmg r(R) from 1025Z until cold-frontal passage ~13Z;

4th: r(slight) began ~0450Z, becoming r(R) from ~06Z to ~10Z, then slight again, csd by 11Z: ocnl pr from midday - 18Z, with tl(slight)r(R) 1305-1335Z: small hail & squall during this latter event; evening pr;

5th: light pr through day;

6th: v.light pr 08-09Z & ~0930Z;

7th/8th: (overnight) r(slight)/r off & on from late evening to ~09Z;

8th: further light dr through day until ~ 15Z;

9th: r(slight)/r early hours, dr 08-0845Z;

10th: r 0130-0200Z, otherwise dr(slight) overnight;

20th: very light pr ~1740Z; pr(R)q 1805-1815Z; pr ~ 21Z;

21st: ocnl pr (light) during day;

26th: r(slight), ocnl r from 1715Z to 1820Z;

26th/27th: r(slight)/r overnight;

29th: ir(slight) early hours, and again between 0615 & 0745Z; further light rain mid-afternoon: very light rain early evening;

30th: ocnl light rain showers during day [ but heavier events in VCNTY];

31st: r(slight) began ~19Z, then r(R) overnight, csd by 01/0730Z Jun.)

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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:.. 00

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 May, 2004

2nd: wet fog early hours to 06Z with measured 'tr' of PPN;

4th: slight thunderstorm 1305-1335Z, with moderate, temporarily heavy rain - short period small hail around 1315Z, accompanied by a squall; thunder/lightning infrequent - circa 1 discharge per 3 or 4 minutes (in contrast to other local reports of more frequent discharges)

21st-24th: very dry air, even first thing in morning with RH << 50% much of time; PPN that fell 20th/evening hardly worth the effort!

29th: very small deposit of dust after rainfall - light grey to off-white: rain occurred mid-afternoon;

 

... 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  08.8  11.0  08.7  00.6    09.8  13.0  tr       tr       -

02  06.4  13.2  05.0  tr(f/w) 13.0  19.4  -        01.4    A

03  08.7  11.8  07.8  01.4    08.6  14.0  07.2     14.3

04  06.4  12.0  05.5  07.1    06.5  11.1  08.8     09.3

05  04.4  09.7  03.2  00.5    08.7  12.9  01.1     01.1

 

06  05.7  11.4  04.3  tr      10.8  15.8  tr       tr 

07  05.8  14.0  04.8  -       12.6  16.9  -        03.5

08  09.0  15.0  08.6  03.5    09.0  11.3  00.1     01.0

09  10.0  11.4  09.8  00.9    11.0  15.6  -        02.3    BC

10  12.0  15.0  11.2  02.3    13.7  20.0  -        -       

 

11  09.6  17.9  07.3  -       14.3  16.7  -        -  

12  08.7  14.3  08.6  -       09.8  13.3  -        -   

13  06.2  13.6  04.7  -       13.6  18.3  -        -       D

14  08.8  16.9  07.5  -       16.2  20.1  -        -   

15  09.0  18.9  07.5  -       15.9  21.9  -        -   

 

16  09.6  19.3  08.0  -       18.2  23.2  -        -  

17  08.6  21.0  07.0  -       20.4  24.5  -        -   

18  10.4  22.0  08.3  -       18.3  23.7  -        -   

19  10.4  21.2  09.2  -       18.0  24.8  -        -   

20  13.3  21.6  10.7  -       16.4  21.7  tr       04.0

 

21  08.3  16.3  07.4  04.0    11.0  15.5  tr       tr 

22  04.1  13.4  02.4  -       11.5  16.1  -        -       E

23  03.4  15.0  02.0  -       14.8  19.0  -        -   

24  05.8  17.5  04.1  -       16.3  20.5  -        -   

25  11.2  18.9  09.1  -       16.1  19.7  -        -   

 

26  11.5  18.1  11.2  -       14.2  18.2  01.3     01.8

27  09.4  14.1  09.1  00.5    11.7  18.1  -        -   

28  07.1  16.6  06.1  -       15.7  20.6  -        tr  

29  13.8  18.2  13.2  tr      15.7  20.4  tr       tr  

30  10.4  16.3  09.5  tr      14.9  19.4  tr       tr      F

 

31  08.3  18.5  06.1  -       16.6  20.9  -        13.3    G

 

Remarks:

A. night max (13.2)[also 24hr max 1st] occurred 02/09Z.

B. night max (11.4)[also 24hr max 8th] occurred around dawn.

C. day min (11.0) [also 24hr min 9th] occurred 09/09Z.

D. night max (13.6) [also 24hr max 12th] occurred 13/09Z.

E. work on screen from 0915Z to 1230Z; minimum correct, as it is the value at 0900Z; maximum possibly slightly contaminated due to follow-up work after replacing thermometer in screen - but am reasonably confident that the value given (16.1) is not far short of the truth.

F. night max (16.3) occurred 30/09Z.

G. night max (18.5) occurred 31/09Z.

 

Number of occasions (24hr periods) THIS YEAR (2004)

maximum temperature >= 21degC (70degF) = 06

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

 

Summary of rainfall for:

Spring 2004: 183mm (113%)

 

Winter & Spring 2003/04: 364mm (106%)

 

Temperature anomaly for spring 2004: +0.7degC