PITSFORD HALL WEATHER STATION NORTHAMPTON, UNITED KINGDOM ANNUAL WEATHER REPORT - 2001 MONTH BY MONTH ASSESSMENT (Statistics follow at end) January January 2001 was a particularly cold month at Pitsford Hall. Average temperatures balanced out at 3.0C, -1.2C below the new long-term average (1971-2000). Air frosts were recorded on 18 days with 26 days recording a ground frost. Snow fell on 2 days (19th & 21st) remaining on the ground for 3 days. Despite the cold, this January was particularly sunny with 86.6 hours of bright sunshine recorded. The first few days of the month were quite mild. Low pressure pushed eastwards bringing some notable wet days (7.8mm on the 3rd). There then followed a prolonged dry period associated with a developing high pressure system to the south of Iceland. Temperatures fell substantially from the 16th with severe overnight frosts (-4.5C air minimum, -8.7C grass minimum on 16th). A weak low pressure system moving through the region triggered snowfall on the 19th and again on the 21st. Snow depth was modest at just 1cm, in contrast to the heavy falls experienced in the last week of December 2000. The 21st onwards saw a significant change in the weather. Temperatures recovered together with some fairly brisk south-westerly winds. The change to milder weather brought some misty and foggy mornings. Much of the fog was persistent throughout the day. Eventually some sunny periods broke through (4.4hrs on 23rd) alternating with some fairly hefty showers (6.6mm also on 23rd). The last days of January from the 27th saw some overnight frosts and overnight mist and fog. A damp day on the 30th was associated with a fairly static occlusion. February Low pressure dominated the scene during the first week of February. A succession of weather fronts resulted in a very wet period from the 1st until the 5th and as the low intensified on the 6th, winds gusted up to 39mph with observations of thunder. The month also started off pretty cold with overnight frosts on the 1st and 2nd, but temperatures then recovered as far as the 7th as south-westerly winds brought in milder air. A ridge of high pressure began building on the 8th and 9th which sent temperatures tumbling under clear overnight skies. The high was short- lived, however, and gave way to a further low on the 11th and 12th which brought some significant rainfall totals including 12.5mm on the 12th. Winds also picked up with gusts recorded in excess of 30mph. A more extensive area of high pressure built up over the next week leading to a dry period until the 23rd. Clear skies overnight resulted in a succession of frosts. Calm conditions and very light winds after the 17th allowed the development of mist and fog which became quite dense in the mornings of the 19th and 20th. From the 21st onwards, high pressure gave way to a developing low to the north-east which brought in a stream of colder air across the United Kingdom. Although cloudy at first, sunshine totals gradually recovered and by the 25th clear skies and the northerly airflow had allowed overnight air temperatures to fall to -4.2C with -9.2C being recorded on the ground (grass). The month ended with some falls of snow as milder air associated with a low to the west met the colder air over the United Kingdom. Falls were slight on the 24th, 25th and 28th with a thin covering remaining on the ground on the 25th (2cm) and 28th (<1cm). March 2001 was a particularly cold and wet month in Northampton. Rainfall was substantially above average. The total of 84.1mm representing 186.9% of the 1971-2000 average. In fact this was Northampton's wettest March since 1979. It was also a particularly cold month with mean temperatures over 2C below the long-term average. March March opened with a generally cold and dry period until the 6th. Winds were generally light, especially on the 4th and 5th, and some very low night-time temperatures were recorded. The precipitation that was recorded was in the form of snow which fell on the 1st and 2nd, lying on the ground until the 3rd. Some reasonable sunshine was also recorded in this period with 7.5hrs being noted on the 5th. The period until the 13th saw low pressure affecting the weather. The 6th was paricularly wet and bands of rain produced substantial falls on the 11th and 12th. Temperatures having recovered from the cold spell at the beginning of the month began to tumble from the 10th. As this low pressure pushed away north-eastwards, a further low came into play. This produced generally wet weather across southern counties of England, although on the 16th and 17th fronts associated with this low pushed northwards and, on meeting the cold air, brought further snow and then heavy rain to the county. A milder spell of weather then followed with temperatures recovering steadily until the 24th, although not before a further front moving up from the south brought snow and heavy rain on the 20th and 21st. The recovery to milder conditions was interupted between the 24th and 26th as the winds swung round to a generally easterly direction bringing some chilly nights, although the county escaped the ground frosts prevalent throughout so much of the preceding weeks. The month ended with another low pressure system tracking through the region. Substantial rain again fell on the 27th. However, the general recovery of temperatures continued culminating in the daytime maximum for March (15.9C) falling on the 31st. April April began on a particularly wet and unsettled theme. A succession of lows passed to the north of the county bringing some particularly wet days on the 3rd (16.0mm) and the 5th (10.3mm). Despite the rain, the county enjoyed some warmth with a daytime maximum of 18.2C recorded at Pitsford Hall on the 2nd. However, overnight temperatures fell sharply on occasion giving a slight ground frost on the 5th and a fairly harsh frost on the 8th (-3.8C). The unsettled spell was broken on the 10th as high pressure built across the British Isles. Some clear spells overnight resulted in several more ground frosts. A second unsettled spell occurred through the third week. Rainfall totals were modest, but the rainfall itself was wintry in nature with hail and brief snow and sleet recorded on the 18th and 19th associated with frontal systems tracking south over the North Sea. Winds were persistently northerly in direction. Overnight temperatures fell substantially giving rise to air frosts on the 17th and 19th. The latter half of the month saw a gradual recovery in temperatures as winds swung round from a generally southerly direction associated with a large and complex low pressure system moving in from the west. There were some periods of heavy rain and/or prolonged rain. 9.6mm fell over 11.5 hours on the 22nd and a further 8.9mm fell over 7.8 hours on the 24th. Despite the rain, there were some days which recorded healthy sunshine totals. As the month came to a close, the rain showers gradually petered out. Daily sunshine values increased up to the maximum daily count for April of 11.3 hours on the 30th, although ground frosts persisted. May May opened on a cool note with air minima falling on consecutive nights producing ground frosts by the 4th and 5th as winds blew from a consistent north or north-easterly direction. Despite some rainfall on the 2nd and 5th, the first week or so was generally settled with pressure building off the coast of Scotland. Some good sunshine was recorded between the 5th and the 7th (10.5hrs on the 5th). A marked warming trend began during the second week. By the 10th daytime maxima had reached 23.7C triggering some thundery showers. Further hikes in temperature over the following few days and the arrival of low pressure resulted in further thundery showers on the 13th and further heavy rainfall totals everyday until the 17th which was particularly unsettled with some heavy downpours and strong winds gusting to 52mph. During this particularly wet period, temperatures progressively fell. From the 18th onwards, high pressure became firmly established across the county giving a prolonged dry spell of weather. Temperatures recovered, but not to the very warm daytime maxima experienced during the second week, the predominant north-easterly wind direction keeping the temperatures pegged down. Several days did, however, notch up some good sunshine totals. The high pressure had slipped away southwards sufficiently by the 27th to allow weather fronts to track across the county. However, rainfall totals were light and daytime temperatures remained warm, generally above 20C. From then on until the end of the month, the weather was generally settled. Clear spells by night forced a progress lowering of mean temperatures, although daytime values remained respectable. Some good sunshine was again recorded, 13.3hrs being clocked up on the 30th. June The month opened on a cool note with a succession of weather fronts tracking south-eastwards across the British Isles. Rainfall amounts were slight, however, across Northamptonshire. High pressure then re-exerted control for a few days allowing a recovery of temperatures from a cool maximum of 14.9C on the 2nd to a more respectable 20.1C on the 5th. However, this warming trend was short-lived as another fairly active cold front pushed south-eastwards bringing a cool spell of weather until the 9th. The passage of the front brought some fresh breezes to the county, winds gusting to 34mph on the 7th and 8th. With the exception of a small low which provided the county with a fair amount of rain on the 9th, high pressure re-established control until the 15th. Sunshine values during this period remained fairly modest. Fairly slack winds made for some fairly persistent cloud. Daytime maxima recovered consistently during this period, reaching a maximum of 21.5C on the 14th. A couple of days of thundery conditions brought to the warming trend to a close on the 15th and 16th as a vigorous low tracked eastwards bringing heavy rainfall on a succession of active fronts. 7.6mm fell at Pitsford Hall on the 16th, representing the greatest 24 hour fall during the month. From then on until the last few days of June, a prolonged dry period emerged with the weather very much controlled by high pressure. Apart from a fairly weak and southward moving cold front on the 21st which gave a brief cool spell of weather, temperatures gradually recovered reaching the mid-to-high twenties by the end of the fourth week. 29.1C was recorded as a daytime maximum on the 26th with overnight temperatures not falling below a sticky 15.8C. Finally, low pressure brought an unsettled end to the month. There were spells of showery rain on the 27th and 29th , but with winds mainly from the south or south-west and a fair amount of overnight cloud, temperatures remained in the mid-to-low twenties. July The first week of July had a generally warm theme. Daytime maxima topped 24C on consecutive days with the highest maximum of July (29.3C) recorded on the 3rd. Although thunderstorms broke out over a large part of England and Wales on the 3rd, the county escaped largely dry. The following two weeks saw a generally unsettled spell of weather. A succession of lows brought cool conditions to the county and there were frequent showers and longer spells of rain. Many of the passing fronts brought thundery conditions to many areas, although the county again escaped with fairly modest falls. The 17th and 18th were particularly wet owing to the passage of an active low and slow moving fronts from the south-west towards the North Sea. 30.4mm fell at Pitsford Hall on 17th over 11.5 hours, with a further 14.4mm falling on the 18th. Some very localised flooding was reported. The fourth week began a gradual warming trend as a ridge of high pressure set in. Winds became very light and calm at times with some good spells of sunshine. By the final week of July daytime maximum temperatures had recovered to the high twenties, 29.1C being recorded on the 29th at Pitsford Hall and temperatures as high as 32C being reported from the south-east. A weak cold front edging southwards as the month came to a close saw a return to cooler and fresher conditions, although remaining fairly warm in the sunshine. August After a reasonably warm start with daytime maxima generally in the low to mid twenties, a cooling trend was observed from the 6th associated with the close passage of an area of low pressure. Apart from the 1st, rain fell on a daily basis becoming particularly pronounced between the 6th and 9th. Some areas experienced some thundery conditions on the 6th, but it wasn't until the 8th and 9th that thunderstorm activity was observed in Northamptonshire. From the 10th onwards temperatures gradually recovered eventually reaching the highest daytime maximum for August of 30.1C on the 15th. Unsettled at first with occasional rain the skies became drier as the days wore on and some respectable sunshine totals were recorded from the 13th to the 15th. Another breakdown in the weather occurred from the 16th onwards. Again thunder was observed in many areas, although not recorded at Pitsford. Daytime maxima fell, although remained fairly respectable at the mid to low twenties. A gradual rise in atmospheric pressure from the 20th onwards brought mostly calm conditions with mean daily wind speeds on the 22nd and 23rd barely reaching 1mph. As the weather turned more humid from the 24th onwards and with the progression of a cold front eastwards over the next couple of days conditions were set for outbreaks of rain and some sharp thundery downpours. On the 25th 3.7mm of rain fell in a matter of minutes. With the passage of the front there was an inevitable downturn in the temperatures. As the month came to a close, the recovery in pressure brought a brief dry and bright spell. However, developing low pressure over the North Sea maintained a north-westerly wind direction which kept the temperatures pegged down. Some light showers were also conveyed to the county on these winds on the 30th and 31st. September Following a dry start, the first few days of September were generally unsettled as bands of rain swept across the county conveyed on north-westerly winds which brought a general reduction in daily temperatures. Much of the rain fell in several short and heavy bursts with thunder recorded further east but in the county. The north-westerly airstream continued to prevail until the 11th and following the initial unsettled period, the first part of the second week was generally dry. Temperatures remained generally depressed. However, this period was the sunniest time of the month with some good daily totals recorded such as 9.9 hours on the 8th. The days from the 12th to the 19th saw a particularly unsettled spell of weather as an intense low tracked southwards across the United Kingdom from Iceland. Temperatures continued to fall sharply especially around the 17th as winds took on a northerly direction. Peak gusts reached 39 mph on the 17th and 18th, the 17th being a particularly windy day. The low temperatures brought the grass minimum within a couple of degrees of freezing (1.5C on 12th and 1.9C on 16th). A brief window opened on the weather between the 20th and 22nd. As winds dropped fairly sunstantial fog developed in the early hours. The unsettled theme then resumed on the 23rd leading towards a very wet end to the month. The mornings saw some further mist and fog patches forming, especially on the 25th and 26th as winds dropped to calm. However, with the winds having swung round to a more southerly direction, the last few days of September were reasonably warm, the 28th being something of a mini-heatwave with a daytime maximum reaching nearly 23C. October The first week of October was generally very unsettled, although initially very mild. Low pressure centred to the north and west prevailed bringing frequent showers and longer spells of rain. Winds were fairly brisk from the south or south-west easing a little on the 4th. The 7th was a particularly wet day with 11.3mm of rain recorded in a matter of a few hours. Despite the rain there were notable windows of bright weather with good sunshine figures recorded on some days. High pressure began to influence the scene during the second week and a quieter spell of weather ensued. It was generally dry from the 10th until the 13th and again some days had some good spells of sunshine. Temperatures began to climb from the 10th onwards and it had become very warm by the 12th with an unseasonal high of 21.3C recorded at Pitsford. Light winds and the high humidity led to mornings with mist and patchy fog between the 12th and 14th. From the 14th onwards low pressure centred to the west and south-west brought mild air across much of the UK. The weather was generally unsettled with rain falling on most days. A succession of active fronts crossed the county from the 19th onwards bringing some heavier spells of rain. 12.7mm was recorded on the 21st and the following day saw the Environment Agency releasing a floodwatch for the River Nene. The county largely escaped the heaviest of the downpours which occurred in neighbouring Cambridgeshire where over 70mm of rain fell in a matter of a few hours. Further spells of wet weather occurred between the 25th and 28th as further lows tracked close-by. A particularly active front crossed the county on the 26th releasing 9.7mm at Pitsford Hall and forcing the Environment Agency to issue another floodwatch this time for the Great Ouse at Brackley. With the exception of a particularly mild day on the 30th, a deepening low brought fresher and breezier weather to the county as the month came to a close. Nationally, this was the warmest October on record. However, in Northamptonshire warmer Octobers have been recorded: 1986 with 14.7C and 1956 with 13.8C. November November open with a reasonably dry, mild and sunny week with pressure high over the region. Sunshine values at Pitsford Hall clocked in at 7.5 hours on the 1st and 4th and daytime maxima reached 14.0C on the 1st and 3rd. Some very wet weather introduced the second week associated with an active low tracking eastwards towards Denmark. The 7th was particularly wet with 7.3mm falling over 6.3 hours. Strong northerly winds also picked up with gusts of 44 mph recorded on the 7th and 49 mph recorded on the 8th. The strong northerlies brought temperatures tumbling with a daytime maximum of just 5.2C recorded on the 8th, a day which also saw the first flurries of snow in the county. The 9th and 10th remained dry as a ridge of high pressure took charge. Clear skies overnight saw temperatures fall sharply to below freezing. A cold front moved through the county on the 12th bringing further pulses of rain and cold polar air. The high pressure which developed following on from this brought a period of calm and settled conditions across the county. Despite some lingering mist in the mornings, there were days with good sunshine and the clear spells by night saw several frosts, the hardest being on the 14th with grass temperatures falling to -6.2C. Increasing cloud on the 16th heralded a spell of traditional anticyclonic gloom which lasted until the start of the 21st. The start of the 4th week was rather changeable. Mean temperatures fluctuated widely as a succession of fronts tracked across the region. Despite some cold nights on the 26th and 27th with ground frosts recorded as low as -4.9C (26th), increasing cloud and south-westerly winds eventually brought in milder conditions, culminating in an unseasonably warm day fuelled by strong southerly winds on the 30th. December A succession of Atlantic lows brought mild but unsettled weather for the beginning of December. The 3rd and 4th were particular wet as low pressure moved eastwards across northern England. Strong winds on the 5th saw trees being uprooted in many areas. Winds gusted to 51mph at Pitsford Hall. The period from the 6th to the 18th saw a prolonged dry spell as anticyclonic conditions prevailed. Sea level pressure rose to 1041.4mb on the 10th and remained consistently between 1035 and 1041mb throughout. Some good sunshine was recorded by day, but clear skies overnight resulted in a succession of foggy mornings from the 8th to 11th and the occasional slight frost. Dense fog on the morning of the 10th reduced visibility to less than 100m across much of the county. An accident involving 30 vehicles caused a 7-mile tail-back on the A14 near Naseby. 9 people were injured, 3 seriously. The daytime maximum on the 10th rose to just 4.0C as the fog persisted. High pressure finally gave way to a series of lows tracking southwards from Norway from the 19th. The southward moving cold air brought frequent air frosts and some severe ground frosts across the county, especially on the 22nd, 23rd (air minimum -4.1C, grass minimum -7.0C) and 24th. Many eastern counties experienced some snow showers, although these were largely absent in Northamptonshire until the final week. Christmas Day in the county began with some wintery showers, but was mainly dry and overcast; the cloud breaking up overnight resulting in a penetrating frost on Boxing Day morning. The final few days of December from the 27th saw a deep low track south-eastwards from Iceland to Denmark. Strong winds, gusting to severe gale force on the 28th, caused some structural damage across the county. In Northampton, the tennis dome on the Racecourse collapsed and parts of the roof of the newly constructed Sol Central leisure complex were lost. Snowfall finally arrived in the county on the 29th with further flurries on the 30th. However, accumulations were modest amounting to just 1cm. With the arrival of the snow the last few days were bitterly cold. Temperatures climbed no higher than 1.8C on the 29th whilst on the 31st overnight air minima had fallen to -4.7C with -8.0C recorded as a grass minimum. Nationally, this was the sunniest December on record. In Northampton this December was the driest since 1963 (11.4mm) and the coldest since 1995 (1.9C). ANNUAL STATISTICS FOR 2001 Air Temperatures Mean maximum: 14.0C Mean minimum: 5.8C Overall mean: 10.1C Difference from the average (1971-2000): 0.0C Highest maximum: 30.1C on 15th August Lowest maximum: 1.6C on 16th January & 2nd March Highest minimum: 18.8C on 29th July Lowest minimum: -8.2C on 18th March Lowest grass minimum: -10.9C on 5th March Lowest concrete minimum: -8.4C on 31st December Rainfall Total: 704.1mm Difference from the average (1971-2000): 113.7% Raindays: 173 Wetdays: 131 Most in a day: 30.4mm on 17th July Duration of rainfall: 438.6 hours Lowest pH: 5.1 on 23rd September Relative Humidity Mean relative humidity (at 0900hrs): 86.8% Sunshine Total: 1564.8 hours Most in a day: 13.3 hours on 30th May Sunless days: 65 Mean cloud cover: 71.3% Wind Number of days with wind from: N 56, NE 29, E 21, SE 28, S 69, SW 25, W 26, NW 84, Calm 26 Mean wind speed: 5.7mph Highest Maximum Gust: 54mph on 27th December Barometric Pressure Mean SL pressure (at 0900hrs): 1014.7mb Highest SL pressure: 1044.7mb on 16th November Lowest SL pressure: 976.1mb on 24th January Soil Temperatures 5cm mean: 8.6C 10cm mean: 9.1C 20cm mean: 10.0C 30cm mean: 10.5C 40cm mean: 10.6C 50cm mean: 11.0C 100cm mean: 10.1C Days with Air frost: 66 Duration of air frost: 464 hours Ground frost: 121 Sleet/snow falling: 14 Snow lying at 0900hrs: 14 Thunder heard: 9 Hail <0.5cm: 6 Hail >=0.5cm: 0 Fog at 0900hrs: 33 -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Pitsford Hall weather station Tel. 01604 880306 Pitsford Fax. 01604 882212 Northampton E-mail office@northantsweather.org.uk NN6 9AX http://www.northantsweather.org.uk Location: 52º 18' N 0º 53' W Altitude: 115m AMSL Local Forecast and Readings: (07967) 438314 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~