OVERVIEW
Generally, 2005 was an average year for thundery activity in England and Wales, which is evident in the selection of thunder day totals in Table 1. However, away from north-west coastal areas which had several thundery outbreaks during the stormy periods in early January and (to a lesser extent) early November, Scotland and Ireland had a quieter year than normal.

Thunder was heard on 22 days at Claygate and 21 days at Coulsdon (both Surrey), and 20 days at Luton (Beds), Cavendish and Bury St Edmunds (Suffolk) and Calthorpe (Norfolk).

WIDESPREAD THUNDERSTORM OUTBREAKS IN 2005
The identification of days of widespread thundery activity across England and Wales has again been based on the geographical "spread" of stations used in Bob Prichard's 1946-1985 survey (J. Meteorology 12, pp 83-86), the automation of various synoptic stations being compensated for by the use of more reports from voluntary observers. Thunder could be described as widespread over England and Wales on 12 days in 2005 (April 19th; May 1st, 21st; June 3rd, 19th, 24th, 28th, 29th; July 28th; Aug 25th, 31st; Oct 19th). The 1946-1995 average was 15 days. The most widespread thunderstorm event over Scotland was overnight 18th-19th June.

The extensive severe thunderstorms of late June across England and Wales were a major feature of the year (Prichard, 2005).

REPORTED INCIDENCE OF OVERHEAD STORMS, LIGHTNING DAMAGE AND OTHER SEVERE THUNDERSTORM EVENTS IN 2005 (overhead thunder is defined as electrical activity reported by an observer to be at a distance of 5km or less, or "close")

Overhead thunder (see also Table 2) was reported on 16 days at Claygate (Surrey) and 13 days at Ware (Herts). The reported lightning incidents (assumed to be only a proportion of the total and subject to future review) were above the average for the previous 11 years (Table 3, Fig 3).

This distribution of lightning incidents and damage (Table 3a), while overall above the mean for the previous 11 years, confirms an enhancement of the usual tendency for the severest activity to occur across central and southern England. It may be noted that 65% of incidents were attributable to three storm episodes: 24th June (54 incidents on a day when nearly all activity was south of the Mersey to Humber); 28th-29th June (the latter date also notable for hail 40mm across on the Essex/Suffolk border); and 31st August. Counties reporting the highest number of incidents in 2005 were: Devon and Dorset with 13 each; Hampshire, the West Midlands and Lincolnshire, all with 12, Somerset with 11 and Cambridgeshire with 10. The south-western counties feature prominently on account of the severe storms on 24th and 28th June, while Lincolnshire was especially hit on 31st August.

Other highlights of the year included:
(a) The spectacular lightning displays from high based storms during the early hours of 1st May, when various areas of activity were visible over a wide area. Several experienced observers in North Devon and Berkshire noted lightning frequencies of 30-60 discharges per minute during the peak spells of activity. Although precipitation was mainly in brief bursts, these included locally damaging hail of at least 25-30mm across (see Hailstorm Summary for 2005).
(b) The massive storm system of 19th June (Fig 1) across the North Midlands and Northern England with severe flash flooding occurring in North Yorkshire and several incidences of hail 25mm diameter or more from the West Midlands to Durham.
(c) The tornadic storms of 28th July, notably in Birmingham and Peterborough (see Tornado Division report)
(d) The early September thundery period in the south; some notable downpours on the 10th September included 74mm in one hour at Chieveley, Berkshire (Pike, 2006) and 25mm in 10 minutes at Claygate, Surrey (Prichard 2005).

Note the severe cumulonimbus cells aligned across Mid Wales, the Midlands and East Anglia. Hailstones 30-40mm diameter accompanied a storm across north Essex and south Suffolk in the late afternoon. 37mm of rain fell in 15 minutes at Capel St Mary. Lightning struck and severely damaged several houses in Hertfordshire and Suffolk around this time. Early in the afternoon a slow moving storm in the Padstow area of Cornwall deposited 51mm of rain in about 75 minutes near St Merryn.
Ref:     RMS Weather Log June 2005.

Table 1. Thunder days in 2005. *Estimate based on TORRO's map of 1961-1985 averages

STATION	COUNTY	2005 total	Average 1971-2000 (unless otherwise stated)	Diff +/-
Calthorpe	Norfolk	20	17 (1987-2004)	+3
Bury St Edmunds	Suffolk	20	16 (Honington 1961-85)	+4
Fleet (Holbeach)	Lincs	19	17 (1988-2003)	+2
Ruddington	Notts	19	17 (1988-2003)	+2
Loughton/Epping	Essex	19	20 (1976-2003)	-1
Buxton	Norfolk	18	15 (1974-2003)	+3
Epsom Downs	Surrey	18	17	+1
Heathrow	London	18	14	+4
Waddington	Lincs	18	14	+4
Cosby	Leics	16	13	+3
Wokingham	Berks	14	15 (Beaufort Park)	-1
Carlton-in-Cleveland	N. Yorks	13	13 (1983-2002)	0
Llangyndeyrn, Carmarth	Dyfed	13	*8	+5
Bulford	Wilts	13	11 (Boscombe D 1957-85)	+2
Lymington	Hants	13	11 (Southampton 1969-85)	+2
Harborne	West Mids	13	13 (1985-2004)	0
Woodford	Gt. Manchester	13	14 (Ringway)	-1
Barnstaple	Devon	12	9 (Chivenor 1957-1973)	3
Stony Stratford	Bucks	12	13 (1986-2003)	-1
Woodlands St Mary	Berks	11	12 (1990-2003)	-1
Oxford	Oxon	10	11	-1
Lyneham	Wilts	10	11	-1
Allerton Bywater	W. Yorks	10	*9	+1
Broadford	Skye	10	7 (Prabost 1956-1980)	+3
Red Wharf Bay	Anglesey	9	6 (Valley)	+3
Penmaen	W. Glamorgan	9	9	0
Gloucester (Longlevens)	Glos	9	10 (Innsworth 1961-1981)	-1
Alvechurch	West Mids	8	14 (Edgbaston 1961-2003)	-6
Velindre	Powys	8	10	-2
Fishponds	Bristol	8	10 (1950-1999)	-2
Hastings	E. Sussex	8	14	-6
Straide, Co Mayo	Ireland	8	10	-2
Drumburgh	Cumbria	6	8 (Carlisle 1961-1985)	-2
Ebbw Vale	Gwent	6	8 (1988-2003)	-2
Shawbury	Shrops	6	9	-3
St Mawgan	Cornwall	8	8	-2
Doncaster	S. Yorks	6	13 (Finningley 1961-1995)	-7
Valley	Anglesey	5	6	-1
Ardpatrick, C Limerick	Ireland	5	13 (1991-2000)	-8
Guernsey Airport	Chan Isles	5	13	-8
Aberporth, Ceredigion	Dyfed	5	8	-3
Eskdalemuir	Dumfries	4	9	-5
Newtownards, C Down	Ireland	4	5 (1975-2003)	-1
Dun Laoghaire, Dublin	Ireland	3	5 (Dublin A/P)	-2
Elderslie	Renfrew	1	7 (Abbotsinch)	-6
Leuchars	Fife	1	5	-4
Aberdeen	Aber	1	3	-2

TABLE 3a. REPORTED LIGHTNING INCIDENTS

Region	2005	1994-2004 Mean
Southern England	84	58
Midlands, East Anglia, Lincs	106	83
Northern England	21	29
Wales	6	9
Scotland	0	7
Ireland	4	10
Channel Isles	4	2
TOTALS	225	198

TABLE 3b. REPORTED LIGHTNING INCIDENTS BY MONTH 2005

Month	net
January	2
February	4
March	3
April	7
May	20
June	118
July	4
August	48
September	10
October	3
November	3
December	1

Of these 225 known incidents, 22 involved people (see Lightning injuries review). 150 of the reported incidents involved strikes on buildings of which 80% caused noticeable damage (some to two or more properties) and 30% caused severe damage (i.e rendering the dwelling temporarily uninhabitable). However (NB) incidents causing little or no damage are less likely to have been reported.

LIGHTNING INCIDENTS

TABLE 2. DURATION OF THUNDER IN 2005
NUMBER OF HOURS OF THUNDER HEARD.

Station (County)	Thunder days/Overhead thunder days	storm hours 2005	comparative notes ref thunder duration
Fishponds (Bristol)	8 (8)	26	mean t hours at Filton 1971-1980 were 23
Oxford (Oxon)	10 (7)	26	mean t hours at Brize Norton 1971-1983 were 24
Bury St Edmunds (Suffolk)	19 (8)	33	mean t hours at Marham 1971-1983 were 41, at Wattisham 1971-1983 mean were 34
Doncaster (S Yorks)	7 (2)	12	mean t hours at Finningley 1971-1983 were 33
Carlton-in-Cleveland (N Yorks)	13 (6)	30	mean t hours at Leeming 1971-1983 were 22
Elderslie (Renfrew)	1 (0)	1	mean t hours at Abbotsinch 1966-1980 were 16

Further details of each month's storms, and their synoptic background, are presented in Bob Prichard's monthly Thunderstorm reports, published in the Journal of Meteorology (e.g. Prichard 2005). Additional accounts of the several outbreaks associated with locally severe hail in 2005 are included in the Hailstorm section of this Annual Review. Further details of relevant lightning incidents are included in the Lightning Injuries and Ball Lightning sections of the Review.

A printable version of this summary is available in word format. Please contact Jonathan Webb for details.

Sincere thanks are again due to all TORRO and other observers who have contributed information on Thunderstorms and associated severe weather in 2005. New thunderstorm observers are always welcome. Further details of either electronic or postal reporting are available from Jonathan Webb.

References:
Pike, W. S (2006). Chieveley again. Weather 61, 31
Prichard, Bob (2005) TORRO Thunderstorm Report June-September 2005. Int. J. of Meteorology 30, 376-385

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