SUMMARY OF CLIMATOLOGICAL READINGS FOR 2001

Location: Tawfield, (Wooden Hill), Great Hollands, in the SW part of Bracknell.

( NGR: SU 854 667; Lat=51^o 23' 30" North: Long=00^o 46' 28" West )
Altitude 80 m
(temperatures degC; rainfall/melted snowfall mm; snow depths cm)
Readings based on climatological day 0900 to 0900 UTC

Notes on individual months:
January: DRY/FROSTY 6TH - 20TH... THEN THE RAIN RETURNS! Notes (re: temperatures): Maxima credited to these dates actually occurred during the following night: 09,20,21,30; (re: precipitation):19th: very light snow 0715 to 0830 (not sufficient to change state of ground at 09Z); further mainly light snow 0930 to 1130, very slight/partial cover .. soon melting; 21st: slight rain/snow mixed 0600Z then slight snow by 0800Z, turning back to slight rain/snow mixed by 0900Z - the 'snow' element ceased around 1000Z, with moderate rain thereafter; 26th: from late AM rain (occasionally heavy)- lasting until about 2300Z, with a period of occasional rain/snow mixed between 1900 and 2100Z; Additional comments: 21st: during sleet/snow event 0600 to 1000Z, surfaces very icy with combination slush, previous hoar frost/ice. Of the 94mm of rainfall this month (5th month in a row with above average precipitation), 64mm/68% occurred in the period 20/0900Z to 26/2100Z.
February: WET/MILD FIRST HALF THEN CHILLIER, QUIETER. FOUR FOG EVENTS. Notes (re: temperatures): minima credited to the following dates occurred during the preceding day: 02,10 (actually during evening of 9th); maxima credited to the following dates occurred during the following night: 01,09; maximum on the 12th occurred between 0900 & 1200Z: Notes (re: precipitation): 6th: pr/R/tlrq 0700-0745Z; 6th: several 'squally' showers PM; 7th: prhq ~ 0300Z; 7th/8th: r/R from late evening 7th to late afternoon 8th=16.1mm; 12th: bulk of rainfall credited to this date occurred 12/0730Z to 12/1700Z - ceased by 12/1900Z (skies cleared rapidly thereafter); precipitation 0.1mm credited to 14th a combination of that morning's hoar-frost melt, and the following night's hoar-frost, dew & fog accumulation; other occasions of 'tr' dew, hoar-frost melt etc., for nights of 15/16th, 17/18th, 18/19th & 19/20th; Very light rain/hail showers mixed during 23rd; 24th/25th: v. light snow late PM to early hours 25th; 27th: slight rain from 1300Z, then r, ocnl R 15Z to 19Z, pr rest of evening; 28th: slight rain/snow-mixed much of day, with light snow ~ 19Z. Additional comments on the weather in February, 2001 Remarkably high number of days fog (some riming) observed at 0900Z: on the evening of the 18th, fog descended rapidly during the evening (certainly thick by 2100Z), and on the morning of the 20th, the fog was dense (<50m) at 0900Z. A month of two halves as regard rainfall: 75.7mm (85% of month total) fell 1st to 12th. A slightly 'wintry' last few days - some snow (but non lying)!
March: ANOTHER WET MONTH. EARLY DRY/FROSTY SPELL. LACK OF SUNSHINE. Notes (re: temperatures): minimum read morning of the 5th (-5.6degC), was lower than anything recorded during the 'official' winter; Notes (re: precipitation): overnight 28th Feb / 1st Mar: slight rain/snow mixed; 1st: light snow showers (no covering); 2nd: intermittent snow grains, with slight snow showers (no covering) PM; overnight 2nd / 3rd: slight snow (patchy covering); 4th: very light snow from 0840Z; 6th: slight, soon moderate/ ocnl heavy rain from 1930Z to around midnight; 12th: local thunder/hail(small); 16th: tlR 2225Z - 2330Z during a wet night 16th/17th with total rainfall in 24hr beginning 09Z/16th=16.9mm; overnight 17th/18th: r/R/ocnl sleet (slight); 20th: sleet or snow grains from 1045Z, ocnl slight snow after midday through afternoon, temporary settling on grass; overnight 20th/21st: r/R (early sleet element); 23rd (early hours) r/R to 05Z; 27th: ocnl r during afternoon; 27/28th (night) sharp-single crack of thunder circa 2220Z, then r/R for much of rest of night; 28th: shower heavy rain/small hail mixed circa 1815-1825Z: slight covering of hail persisting at least 1hr. 30th/31st: very variable local rainfall - some local stations little or no rain, we appear to have had the most (1.8mm)! Additional comments on the weather in March, 2001 The minimum temperature recorded on the morning of the 5th was the lowest temperature in the 'broad-winter' period, certainly lower than anything in the 'official' winter Dec-Feb. After rain 27th/28th, lawn waterlogged - and stayed so at least until 29/0900Z: most unusual given soil type (sandy) & marked slope of garden. (CLICK HERE FOR MORE ON THE PRECIPITATION TOTALS OF THE PAST 6 AND 12 MONTHS)
April: RATHER WET (AGAIN!); EXTENDED CLOUDY SPELLS - CHILLY. Notes (re: temperatures): apart from being a disappointingly chilly month, none. Notes (re: precipitation):3rd/4th: ocnl R overnight; 8th/17Z to early hours 9th: r/R=14.6mm; 18th: 1335 - 1425GMT pr(slight)h(slight/<0.5cm)q; 20th: several pr/h(<0.5cm dia) & q during period 1310 to 1530GMT); 22/1600 to 23/0400 r(R) much of time; 24/0615 to 24/1530 much of time=4.0mm; 25th: ocnl mod/heavy rain-showers; 28th: heavy showers from late AM, incl ph(<0.5 cm dia) ~17Z; 28th/29th: overnight (until 29/0700Z) r/R; Additional comments on the weather in April, 2001 thunder heard briefly PM 2nd; Eighth consecutive month with over 80mm of precipitation.
May: DRY OVERALL. TWO WARM SPELLS:1ST THUNDERY, 2ND STRONGLY SUNNY: Notes (re: temperatures): 17th: 'day' maximum (up to 18Z) was just 8.0degC, 24hr max 17/0900Z to 18/0900Z=11.3, which occurred *at* 18/0900Z; Notes (re: precipitation): 10/0030 to 10/0145Z tlr/R accounted for the 5.8mm of rain credited to the rain-day 9th; 11th: t 1415Z, & var. times between 1440Z & 1615Z, with light/moderate rain; 15th: t 1605Z to 1630Z; 16th: pr/R 16/0730Z to 16/1000Z, t circa 1230Z, tlrq 1345Z to 1410Z; (total rainfall 15/0900Z to 17/1800Z=29.1mm (68% of month total);(see also remarks re dry spell in general notes below) : Additional comments on the weather in May, 2001 During night 9th/10th, vivid lightning (mainly CC) display during a passing trough-line storm 0030 to 0145Z; 16th: very showery day with marked Cb development, squally winds (no rotation) & short/sharp downpours; 17th: a thoroughly cold, miserable day with persistent rain (5mm)/(day-max 8.0degC) & a strong, gusty wind; 21st to 26th: although temperatures not spectacular, with near-unbroken sunshine (ocnl Ci/COTRA and later Ac flo/Ci in), it was a welcome fine spell after the months of rain; as of 26/0900, we had had 8 consecutive periods of 24hr without *any* rain at all - the longest such dry period since the second half of July, 2000; 27th: very small deposit of dust (light-grey colour) after intermittent rain which fell at various times between 0700GMT and 1330GMT; period (by rain-days=14) 18th to 31st, longest period without measurable rain since March, 2000.
June: DRY OVERALL: COOL FIRST HALF, WARM/HOT SPELL LAST WEEK: Notes (re: temperatures): Using nearby Beaufort Park data, the night 8th/9th was probably one of the three or four coldest June nights in the local area in the last 50 years & the coldest June night since 3rd/4th June 1991; 26th: warmest day this site (any month), since 31st July, 1999. Notes (re: precipitation): The 12.9mm recorded on the rain-day beginning 15/0900Z represented over half of the eventual monthly total. Additional comments on the weather in June, 2001 The moderate shower overnight 9th/10th brought to a (temporary) end a prolonged spell of dry weather that began 18th May: 22 days, to none of which was credited more than 0.2mm, with a total for that period=0.5mm; marked change to cyclonic, showery weather occurred 15th & 16th, but dry (& warm, temporarily hot ) weather re-established thereafter.
July: HOT/HUMID FIRST WEEK; THUNDERY MID-MONTH; HOT LAST WEEK. Notes (re: temperatures): maxima credited to the following dates actually occurred around 09Z the following day: 19th, 22nd. Notes (re: precipitation):7th/8th: overnight ocnl heavy rain; 10th: squally showers afternoon; 13th: heavy rain (~10mm) with tl afternoon (see below); 17th/18th (late PM 17th through night 17/18)=9.0mm from r/R; Additional comments on the weather in July, 2001 4th: thunder heard, light rain ~1520Z; 7th: tl 1500Z, tlr 1525Z, r/r(slight) 1600Z, tlr(slight) 1630Z .. ceased by 1640Z; 11th: F6(G7) winds much of day - passing showers; 13th: tlR/h(small) 1530-1550Z; 14th: t/hR 0947 to 1025Z;
August: WARM SPELLS; PLENTY OF RAIN IN SHORT, SHARP BURSTS. Notes (re: temperatures): (see note re: 26th in general comments below); Notes (re: precipitation): 2nd: r/R from 13Z to mid-evening. In period 02/13Z to 02/18Z (5hr)=19mm; 9th: r/ocnl R (initially thundery) 1045Z to 21Z=15.7mm; 26th: r(slight), ocnl r from ~10Z to d (slight) by mid-evening; Notes (re: thunder events): 8th: tl(slight)r circa 1215Z; 9th: tl(slight)r(slight) 1045Z to 1125Z; 19th: single clap t heard (slight r) circa 1155Z; 26th: single clap t heard (slight r > mod. r) circa 1200Z; 31st: tlr circa 1335Z: Additional comments on the weather in August, 2001 26th: a thoroughly unpleasant late-August day, co-inciding with the Sunday of the Bank Holiday w/e. The nominal maximum of 20.0degC, overstates the true picture as temperatures fell slightly from early afternoon as the steadier rain, with markedly gloomy skies (?day-darkness) set in. Although significant thunder activity reported close-by, only single clap heard here. .... and the SUMMER: Mean Max=22.7 Mean Min=12.3 Mean Daily=17.5 Total Rainfall=147.6mm (wetter than last year by 42 mm): Days temperature >=25degC=24; Days temperature >=30degC=3; No. days thunder heard:=9
September: OFTEN CLOUDY, UNREMARKABLE MONTH WITH SEQUENTIAL CHILLY DAYS. Notes (re: temperatures): Sequence of quite chilly days just after mid-month with maxima 17th to 19th inclusive=13.1, 13.8, 13.9; 28th: one fine late September day with near unbroken sunshine and maximum temperature=21.7degC. Notes (re: precipitation): r/R 02/22Z to 03/05Z=17.0mm, with peak intensity circa 03/02Z (this is the wettest day of the month, credited to the 2nd, but bulk of rain fell early hours of the 3rd); 28th/29th combination of r/pr=12.5mm in 24hr to 29/0900Z; 30th/1st Oct - evening/night - r(R). Notes (re: thunder events):(none); Additional comments on the weather in September, 2001 (none)
October: NOTABLY MILD - WET OVERALL. Notes (re: temperatures): 20th: min. credited to this date probably occurred early in night 19th/20th - temperature end of night around 15degC; 21st: a chilly, windy, overcast & damp day - 11.6degC max. Notes (re: precipitation):30th Sep/1st Oct r/gusty winds (ocnl F6) overnight, but rainfall (6.2) credited to September total; 6th pr(slight)/ pr during day; 6th/7th r(R) overnight - total rainfall 06/09Z to 07/09Z=8.8mm; 7th persistent rain started 1150Z (slight) becoming moderate by 1210Z, with wind rising F5, with sharp gusts - by 1330Z, ocnl heavy rain and this mix of moderate, ocnl heavy rain lasted to 1630Z, when change to high-base cloud, light/intermittent rain - wind easing considerably (CF passage). Total rain this episode: 16.3mm - Short break, then from 18Z through to overnight period, periods moderate rain, or heavy rain showers (particularly intense circa 1830Z, with sharply gusty wind - markedly fibrous Cb observed in vicinity). Total rain this episode: 8.4mm. TOTAL recorded in rainday 7th October, 2001 (i.e. 24 hr from 070900Z) 25.0mm; 8th pr(R)q 1220Z to 1235Z (i.e. 15 mins)=8mm; further pr rest of afternoon on 8th; 11th - the total of 0.1mm is composed of dr on the 11th (csd about 10Z) and overnight fog 11th/12th; 14th/15th: r(ocnl R) overnight, plus pr 15/07Z to 15/08Z=total 11.7mm; 17th/18th(overnight) r(R)=6.8mm, csd by 0530Z; early 20th: thunderstorm then ocnl heavy rain ~0115Z to 04Z=10.2mm; 21st: r(slight)/ocnl r much of daylight but only 2.0mm (in contrast to high totals not too far away to the east & northeast); 22nd/23rd: rain from 22/18Z to early hours 23rd (ocnl R)/csd by 23/0430Z=12.5mm; 24th: tl(slight) + pr(moderate) PM=4.4mm; 27th/28th (evening/night) r(slight) started ~ 27/2100Z - off/on all night (ocnl moderate) - csd circa 28/08Z; Notes (re: thunder events):1st: t ~ 1410Z (single prolonged rumble only); 17th: 1730Z to 1750Z tl(slight rain), csd by 1815Z (lightning still visible); 20th: 0100Z lightning (CC/sheet) > 0115Z tl(slight)r(slight) > 0135Z tlr: thunder csd circa 0145Z (r/R continued around 2 hr thereafter (see above); 24th: 0515Z - 0610Z distant (CC) lightning only seen, no thunder; tl(slight)r(slight) 1210Z to 1230Z; Additional comments on the weather in October, 2001 7th: (during period heavy rain) - Marked shear in the lowest 700m observed from clouds during afternoon circa 1330Z when shreds of stratus (lowest cloud in heavy rain) observed around 300m to be moving from slight south of east, and next layer (SC) at circa 600m coming almost due south. Must have been exciting on approach at Heathrow given the strength of the wind. Winds during period 07/1300 to 07/1430Z probably reached F7 (mean) temporarily (less than 10mins), but no damage locally observed; 12th early f (up to about 08Z);

Comment on rainfall for this year until end October, 2001:
** Rainfall recorded January to end October 2000=756.9mm
** Rainfall recorded January to end October 2001=777.9mm 2000 was a notably wet year - this year overall (so far) is also turning out to be notably wet. It is even more remarkable if you strip out the 48.3mm recorded from a single event (the 'Bracknell Storm') of May last year, then this year we are running comfortably ahead of last-year's values.
November: DRY OVERALL. DAMP/BREEZY LAST FEW DAYS. OFTEN MILD. Notes (re: temperatures): 15th: maximum recorded occurred overnight 15th/16th; the minimum recorded/credited to 09Z/16th actually belongs to the previous morning - no frost overnight 15th/16th; 25th: 13.8degC occurred before midday - sharp drop temperature passage of ana-cold front circa 1550Z; 28th maximum recorded occurred at 29/0900Z; 29th minimum recorded belongs to the 28/0900Z reading (mild/breezy night 28th/29th); 29th (maximum) actually recorded 30/0900Z; Overnight 29th/30th minimum 13.3degC (c.f. 24hr min. of 11.4); Notes (re: precipitation): overnight 7th/8th rain=8.8mm; 25th: r(slight)/ocnl r 1530-1700Z (ana-front)=6.0mm; 29th (early hours) short period r=4.0mm; 30th (early hours) r(slight)/r=6.1mm; 30th/1st Dec: most of rain overnight (contributing to the 7.5mm recorded at 01/0900Z Dec.) actually fell after midnight - technically in December. Notes (re: thunder events):(none). Additional comments: Warmest day of the month was the last one by a long way, yet the rest of the month could not, by any stretch of the imagination, be termed 'cold'!
December: DAMP START, THEN QUIET/COLD/DRY - OFTEN FROSTY BUT SUNNY. Notes (re: temperatures): 4th: maximum (10.5) occurred 05/0900Z; 12th: the T(min) logged (-2.5) occurred earlier in night (prob. before midnight) - actual temperature at 12/0900Z=+1.0degC; 16th: the T(min) logged (-1.2) belongs to the previous morning - temperature overnight 15th/16th well above freezing; 20th: T(max) (4.2) occurred at 21/0900Z; 23rd: T(max) (4.7) occurred at 24/0900Z - day max on 23rd (09-21Z)=0.7degC; 24th: T(min) (-4.6) recorded belongs to AM on the 23rd - temperature that day didn't rise above 0degC until around 1400Z; 31st: temperature above zero for only a couple of hours - rapid fall towards dusk : temperature at 31/2100Z=-4.0degC. Notes (re: precipitation): 4th: r(ocnl R) 0200-0330Z; 4th/5th: r(slight)/r much of night, with most recordable rain early hours 5th; 23rd/24th - r(slight) after 21Z until early hours=0.3mm, plus air-mass change; 25th: r(slight)/ocnl r, slowly dying out PM; 29th: slight rain/snow mixed 04Z to 0830Z; slight snow shower ~10Z; 30th: ph/rs(slight) 1415Z; Notes (re: thunder events):(none). Additional comments on the weather in December, 2001 Both 'snow' events logged were in the 'rain/snow mixed' category - no 'proper' snow observed; 0.5mm of month's ppn total due to dew, heavy hoar frost deposition and/or dense freezing fog moisture; Some remarkably clear nights;

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