Bracknell (Tawfield)
Some notes relating to the rainfall of December 2002, the rainfall of November and December combined, and the year 2002 overall.
eLTA=estimated long-term average (based on 1961-1990)

NOTES PERTAINING TO DECEMBER ONLY:
Total rainfall (2002) up to 01/0900Z JAN 2003=141.3 (214%)
Total rainfall (2000) ..............=110.7 (170%)
Total rainfall last 7 days ....=79 mm (this represents roughly 120% of the 'average' all-December rainfall in this 7-day period)

NOTES PERTAINING TO NOVEMBER & DECEMBER ONLY:
Total rainfall (2002) for these two months=333 mm (this represents half (50%) of the eLTA for the whole year, and is 82 mm more than the same period in 2000)

NOTES PERTAINING TO SEPTEMBER TO DECEMBER INCLUSIVE: Total rainfall (2002) for these 4 months=441 mm (this represents 66% if the eLTA for the whole year, and is 74 mm LESS than the same period in 2000)

NOTES PERTAINING TO RAINFALL FOR THE WHOLE YEAR: [ eLTA=667mm ] Rainfall in 2002=1050.8 mm (157 % of eLTA)
Rainfall in 2000=1007.6 mm (151 % of eLTA)

Notes re. events >=40mm in the standard rain-day:
1. In 2000, the 'Bracknell storm' a purely local event, accounted for 47.1mm falling in under 2hr on the evening of the 7th May.

2. In 2000, the only other really 'high-profile' (& widely experienced) rainfall event occurred in the period early hours 27th Oct. to dawn 30th, when 76.3mm fell, or 43% of that October's total.

3. In 2002, on July 31st, 2 separate 'tropical-style' downpours (WITHOUT THUNDER), totalled 56.0mm in around 3.5 hrs total duration. (Thunder was heard this day, but not associated with these high local rainfall events.)

4. In 2002, on August 7th, 45.1mm was recorded, the greater part falling in under 4hr evening 7th & early hours 8th - accompanied by thunder - the 'evening' event dramatically so.

5. Technically more 'thundery' events in 2002 (about the estimated average for this location), but as noted above, thunder often didn't always accompany the really intense rainfall; this contrasts with 2000, when the remarkable May thunderstorm (with hail) did contribute significantly to the annual total.

6. Although the number of 'rain-days' (i.e. amounts in standard climatological day >=0.2mm) were not too different, the pattern of rainfall was different. Using the following semi-arbitrary divisions:
mid/late winter (Jan/Feb): MLWIN
early spring (Mar/Apr): EYSPR
spring/early summer transition (May/Jun): SPSUT
high summer (Jul/Aug): HISUM
autumn/early winter (Sep/Oct/Nov/Dec): AUTEW

Of note:
(a): A shift in rainfall from the 'early spring' period back to the 'late winter' period.

(b): Much more rain (over twice amount) this 'high summer' gone than in 2000, but only a slight increase in the numbers of day - i.e. for each day's rain, more of it.

(c): 'autumn/early winter' 2002 rainfall down, both in numbers of days, and total rainfall - perhaps contributing to the fact that we (western Home Counties) have (so far) got away with minor/local flooding only - September 2002 was dry, as was the first 10 days of October.

(d): The 12-month (calendar) total for 2002 of 1051mm is NOT the highest 'any-12 month' total: that occurred from April 2000 to March 2001 (incl.), with 1208mm.

I don't think any of this has anything to say about the 'Global Warming' debate, one way or another. It was only back in 1996/97 - "a blink of the eyelid" in climatological time, that I had on my web site a set of graphs showing how dry the weather had been. What we can say is to emphasise (if not already appreciated), just how volatile the climate can be on a short time-scale.

Martin Rowley, 4th January, 2003