Summary for December 2006

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

HEADLINE:VERY MILD FIRST-HALF; COLD/FOGGY FROM MID-MONTH: WINDY, WET END

(last updated: 31/1400 JANUARY .. correction)

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; )

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TEMPERATURES ETC.

Highest day maximum (date):... 13.5(04)

Highest 24hr maximum (date):.. 14.0(04)

Lowest night minimum (date):...-01.9(22)

Lowest 24hr minimum (date):...-01.9(22)

Lowest overnight grass minimum (date):...-01.7(10)

[ number of days grass minimum < 0degC: ... 07 ]

[ Lowest day maximum (date):... 00.4(21)]

[ Highest night minimum (date):... 12.6(05)]

A. Mean Day (09-18Z) maximum: ... 08.5

A. Mean Night (18-09Z) minimum: ... 05.4

A. Mean of Day Max & Night min: ... 06.9

B. Mean 24hr maximum:... 08.9 [+ 1.3 anomaly wrt eLTA of 7.6degC]

B. Mean 24hr minimum:... 04.5 [+ 1.5 anomaly wrt eLTA of 3.0degC]

B. Mean of 24hr max & min:... 06.7 [+ 1.4 anomaly wrt eLTA of 5.3degC]

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

Nr of days minimum at 09UTC <0.0degC:04[dates: 20-23]

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:... 93.2 [133% of eLTA of 70mm]

Highest 24hr total:............... 20.2(29)

No. days PPN total >= 0.2:16

No. days PPN total >= 1.0:13

No. days PPN total >=10.0:03

No. days PPN total >=25.0:00

(Notes relating to precipitation & allied observations:

1st: r(slight), ocnl r 0330-0800Z, then idr(slight) [ rainfall up to 0900Z credited to November total]; period dr ~0945/1000Z & 1615-1700, otherwise ocnl dr(slight) rest of daylight;

1st/2nd: r(slight)/r (ocnl R/isol tl) early evening 1st, further periods of rain late evening 1st to ~0400Z/2nd;

2nd: a couple of light rain showers between 20 & 21Z;

3rd: r/R from ~03Z (wind increasing), moderate ceased 0850Z, then ir(slight), ceased by 0915Z;

4th: pr(slight/moderate) 0700-0715Z; r(slight), ocnl r, 1525-1700Z;

4th/5th: periods r(R) overnight;

5th: ir(slight), ocnl moderate, 08-11Z, pr(slight) afternoon & evening;

6th: pr(slight) early PM;

7th: lengthy periods r(R) & strong/squally winds, from ~00Z until 0730Z (frontal squall/R ~0645/0650Z); tl(slight) r/R (squalls) between 1015 & 1045Z; further pr(slight/moderate, isol heavy) thereafter lingering into the evening;

8th: pr 0300-0315Z; sporadic/light r 0935-1145Z;

10th: r(slight) from 1420Z, then continuous, becoming ocnl moderate/isol heavy from ~1600Z, lingering well into the evening;

10th/11th: periods dr(slight)/ocnl dr or r overnight, becoming rr by 11/09Z with r(R) for a couple of hours more, ceased (as light rain) by 11/1145Z;

12th: sporadic rain(short-period moderate) 1930-2100Z;

15th: ir(slight) ~1250Z & ~16Z; ir(slight) from 2005Z, becoming r(slight)/r between ~16/00Z & 06Z;

18th: r(slight), isol r, 0700Z – 1130Z, then ir(very slight) until ~1230Z;

27th: period dr(slight, ocnl moderate) ~01-06Z; ir(slight/few drops) between 18 & 19Z;

27th/28th: id(slight) overnight, ceased well before 06Z;

28th: id(very slight) during day;

29th: sporadic r(slight)/r (ocnl drizzle late afternoon) from 09Z to evening, then . .

29th/30th: r(R), with strong, squally winds overnight until ~0615Z;

30th: r/R 1330-1610Z, with intense 'line-convection' between 1550 & 1600Z (visibility <1km); further ir(slight) from ~1745Z through evening;

31st: r(R) between 0030 & 0200Z: r(slight), soon r from 0845Z, then periods r(slight)/r for rest of day, with r/R from 1745Z to 1815Z. ir through evening;

1st(Jan/to Dec. a/c): pr/h ~05Z;

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OTHER TOTALS

Number of days thunder heard: (dates).. 02 (01,07)

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

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).. 04

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Additional comments on the weather in December, 2006

3rd: frontal passage between 0630 & 0645Z with wind veer/sharp easing in strong wind after short-lived squall (but wind never particularly strong here in general ~ F6, short period F7 at worst).

19th: mist > fog by 0200Z, with periods well below 200M after 04Z; the fog 'wet' enough to produce 0.1mm in gauge at 09Z.

20th: wet fog all day with 0.1mm in gauge at 18Z.

21st: wet fog all day with 0.1mm in gauge at 18Z.

persistent fog (vis.<1km) from afternoon 19th to ~0745/0750Z 23rd.

18th/19th (night) –> 22nd/23rd (night): total 'precipitation' recorded from the entire fog/heavy dew/rime event = 0.6mm

[thunder]

1st: single extended rumble of thunder (CC?) 1847Z, followed immediately by a ~5min spell of heavy rain.

7th: slight thunderstorm (a few deep/medium-distance, extended rumbles) between 1015 & 1045Z, accompanied by moderate/heavy rainfall: small hail reported about 1km away, but none here. Some squalls accompanied the heavier rain (local minor tree debris).

[snow]

Nil

... 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 08.4 11.0 06.7 01.8 11.0 12.7 02.5 06.6 A

02 09.3 12.7 08.1 04.1 08.2 10.4 - 06.6

03 07.6 10.6 05.1 06.6 07.6 09.9 tr 00.1 B

04 07.3 09.4 04.9 00.1 07.8 13.5 00.5 01.5 C

05 12.6 14.0 11.2 01.0 10.5 13.0 00.9 01.0 D

06 08.2 10.5 06.2 00.1 06.7 09.5 tr 08.3

07 06.3 11.2 03.8 08.3 06.6 10.5 03.9 04.3 EFG

08 06.8 09.1 05.6 00.4 05.3 08.3 tr tr

09 02.2 05.3 00.1 tr(w) 02.5 07.0 - tr

10 00.4 04.2 -01.7 tr(w) 01.6 09.0 02.6 08.9 H

11 09.0 11.8 08.2 06.3 07.6 11.7 02.8 02.9 I

12 04.1 07.6 01.9 00.1(w) 05.6 10.6 - 00.1 J

13 10.0 11.2 08.5 00.1 11.2 12.2 - - KL

14 11.3 11.8 10.0 - 11.4 13.0 - -

15 10.3 12.3 08.2 - 10.3 11.6 tr 05.5

16 04.4 11.2 02.8 05.5 04.0 07.0 - 00.1

17 02.3 04.0 -00.4 00.1(w) 03.2 07.2 - 01.7

18 03.1 05.7 -00.1 01.7 05.7 07.1 00.3 00.4

19 01.8 06.7 –01.0 00.1(Fw) 01.7 03.3 - 00.1 MN

20 –00.6 02.5 -00.2 00.1(Fw)-00.6 01.3 00.1(f) 00.1 OPQ

21 -01.4 00.0 -01.3 - -00.8 00.4 00.1(f) 00.2 R

22 -01.9 00.2 -01.5 00.1(fx)-01.7 00.6 tr(f/F) 00.1 ST

23 -00.4 00.7 00.0 00.1(F) 00.7 04.4 - - UVW

24 04.3 04.7 04.2 - 04.7 06.4 - - XY

25 05.7 06.2 05.3 - 05.3 06.0 - -

26 04.6 05.3 04.3 - 04.6 06.3 - 00.4

27 03.9 05.9 03.7 00.4 03.9 05.3 - tr Z

28 04.4 09.9 04.1 tr 08.4 10.5 tr tr AA BB

29 05.0 08.4 03.4 - 06.6 09.7 02.9 20.2 CC

30 09.7 12.6 08.1 17.3 09.6 11.9 11.6 13.1 DD

31 07.7 09.6 05.6 01.5 09.0 12.2 05.5 11.1 EE

Readings taken at 0900 and 1800 UTC. Where the NIGHT maximum or DAY minimum are significantly different from 24hr values, this will be noted in the listing against a 'Remarks' letter. There are two mean 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) .. 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.

Remarks:

A. night max.(11.0), also 24hr max 30th Nov, occurred 01/09Z

B. night max.(10.6), also 24hr max 2nd, occurred 03/09Z

C. day min.(7.8), also 24hr min 5th, occurred 04/09Z

D. night max.(14.0), also 24hr max 4th AND highest for the month, occurred late evening/early hours

E. night min.(6.3), also 24hr min 7th, occurred early evening on the 6th

F. night max.(11.2), also 24hr max 6th, occurred between midnight & dawn

G. day min.(6.6), also 24hr min 8th, occurred late afternoon 7th

H. day min.(1.6), also 24hr min 11th, occurred 10/09Z

I. night max.(11.8), also 24hr max 10th, occurred late in night

J. day min.(5.6), also 24hr min 13th, occurred 12/09Z

K. night max.(11.2), also 24hr max 12th, occurred 13/09Z

L. day min.(11.2), also 24hr min 14th, occurred 13/09Z

M. PPN measured at 09Z (0.1mm) a combination of heavy dew & 'wet' fog

N. 'evening' reading at 21Z

O. PPN measured at 09Z (0.1mm) a combination of heavy dew/fog deposit

P. confirm that grass min. is higher than air min.

Q. see comment above re: wet fog all day

R. PPN measured at 18Z (0.1mm) from 'wet' fog

S. PPN measured at 09Z (delayed) from overnight rime/fog

T. day min.(-1.7), also 24hr min 23rd, occurred between 09 & 10Z 22nd

U. night max.(0.7), also 24hr max 22nd, occurred 23/09Z

V. PPN measured at 09Z (0.1mm) from 'wet' fog

W. day min.(0.7), also 24hr min 24th, occurred 23/09Z

X. night max.(4.7), also 24hr max 23rd, occurred 24/09Z

Y. day min.(4.7), also 24hr min 25th, occurred 24/09Z

Z. day min.(3.9), also 24hr min 28th, occurred 27/09Z

AA.night max.(9.9), also 24hr max 27th, occurred late in night but before 09Z

BB. 'evening' reading at 21Z

CC. day min.(6.6), also 24hr min 30th, occurred 29/09Z

DD. night max.(12.6), also 24hr max 29th, occurred overnight, but before dawn

EE. day max/also night max.(12.2), also 24hr max 31st, occurred 31/18Z

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Number of occasions (24hr periods) THIS YEAR (2006)

maximum temperature >= 21degC (70degF) = 92

minimum temperature >= 16degC (61degF) = 24

Rolling 12 month temperature anomaly: +1.4 (was +1.2 end last month)

Rolling 12 month rainfall: 108% of eLTA (was 103% end last month)

Rolling 24 month rainfall: 94% of eLTA (was 91% end last month)

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Total rainfall for this year (2006): 759.6 mm, representing 108% of the 'average' that we should have by the end of December / Year.

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[ANNUAL]

[TEMPERATURE]

Anomaly for the whole year (based on 24hr maxima/minima) was +1.4degC. By this measure, in a composite series 1971-2006, it is the warmest year, beating 1990 & 1999 by 0.2degC.

Up to April inclusive, the year was 'nondescript' with below-average months balancing above-average ones; from May onwards, a strong positive bias shown, with 7 (out of 8) months showing an anomaly >+1degC, and three months (July, September & October) having anomalies >+3degC.

[THUNDER DAYS]

Total number of days 'thunder heard' = 27 (c.f. estimated local average of the same measure of ~15). In fact, given the difficulty of maintaining a continuous watch on 'thunder heard' events, I may have missed a couple of 'flash-single bang' events, so the true total may be higher.