Monthly Weather Review - Pitsford Hall

Headline: The wettest August locally since 1917. Very changeable marked by a succession of Atlantic lows and trailing frontal waves.

Low pressure centred over Shetland dominated the picture at the start of August, although a ridge of high pressure began to build in temporarily from the south-west during the first two days. The 1st and 2nd were dry days consequently across Northamptonshire with spells of sunshine, more especially on the 2nd and just a light breeze. However, the high began to retreat on the 3rd as frontal systems drove in from the west introducing outbreaks of mainly light rain.

Another Atlantic low swept across a few days later on the 7th , but this system had lost much of its strength as it moved eastwards and the county saw little more than trace amounts of rainfall and cloud. Following another brief lull with high pressure filling the gap on the 8th, more substantial rain was delivered to the county on the 9th. In fact, the 9th saw the start of a wet spell as low pressure dominated the picture across the British Isles becoming fairly stationary finally winding up over the North Sea on the 14th. The 13th and 14th were particularly wet across Northamptonshire with 7.3mm and 11.7mm falling on respective days at Pitsford. With the wind also swinging round from the north it also became cool for the time of year with temperatures on the 13th struggling at 16C.

By the 15th high pressure west of Ireland began to push eastwards across the UK. Whilst this brought some good spells of sunshine on the 15th and again 16th, it didn’t remain completely dry. Low pressure over the Netherlands intensified and introduced a brisk northerly wind across eastern areas and a weak frontal system introduced outbreaks of rain. Conditions then became gradually more cyclonic across the British Isles dominated by two distinct low pressure centres to the east and west. Frequent showers separated by spells of sunshine marked the weather across the county during this period until the 19th which saw a fairly prolonged spell of rain overnight into the 20th. However, this rain would clear to warm sunshine later in the day.

A deep low tracked past the north-west over the next couple of days and this left a trailing frontal wave across the southern half of the UK. It was this front that was responsible for a particularly wet day on the 22nd as 34.5mm of rain was recorded in just over 8 hours at Pitsford. Localised flooding became widespread across the county as severe weather warnings were issued.

As the main area of low pressure moved away to the north-east, conditions settled down for a while on the 24th, although it remained fairly windy. Peak gusts at Pitsford reached 41mph, unusual for the summer. However, the dry spell would be a relatively short window as an active low moving up from the south-west would deluge the county with further prolonged and heavy rain on the 25th and 26th. A total of 42.6mm of rain was recorded in the 48 hour period from 0900GMT on the 25th to 0900GMT on the 27th. Again it remained fairly breezy.

As the month came to a close, high pressure over the North Atlantic would extend its influence towards the British Isles, yet it failed to prevent the ingress of yet more weather fronts from the north-west on the 28th which produced a couple of unsettled days across the county marked by a fresh westerly breeze and sharp showers. Nevertheless, the high finally managed to position itself right across the British Isles on the 31st to ensure at least that the August Bank Holiday would be fine and dry with plenty of warm late summer sunshine.

Air Temperatures    
The Highest Maximum: 24.1 C on 20th
The Lowest Maximum: 14.4 C on 26th
The Highest Minimum: 17.5 C on 21st
The Lowest Minimum: 6.4 C on 31st
The Mean Maximum: 20.0 C  
The Mean Minimum: 11.6 C  
The Overall Mean: 15.8 C  
Difference from the Monthly Mean: -0.7 C  
    
Solar Radiation    
Maximum (at 0900): 673.0 W/m^2 on 9th
Mean (at 0900): 258.9 W/m^2  
    
Relative Humidity:    
Highest Relative Humidity (at 0900): 96.2 % on 21st
Lowest Relative Humidity (at 0900): 62.1 % on 9th
Mean Relative Humidity (at 0900): 83.0 %  
    
Dew Point:    
The Highest Dew Point (0900): 17.8 C on 21st
The Lowest Dew Point (at 0900): 7.4 C on 30th
The Mean Dew Point (at 0900): 12.2 C  
    
Rainfall:    
Total: 141.5 mm  
Percentage of the Monthly Mean: 271.6 %  
Duration: 95.0 hrs  
Highest 24 hour fall (0900 to 0900): 34.5 mm on 22nd
Rain Days (>/=0.2mm): 17   
Wet Days (>/=1.0mm): 14   
    
Sunshine:    
Total Duration of Bright Sunshine: 129.6 hrs  
Sunniest day: 10.9 hrs on 31st
No. of days without sunshine: 2   
Percentage of the Monthly Mean: 61.6 %  
Cloud cover (mean at 0900): 6.2 oktas 77.5 %
    
Pressure (reduced to sea level):    
The Highest Pressure (at 0900): 1027.5 mb on 31st
The Lowest Pressure (at 0900): 998.1 mb on 23rd
Mean Pressure (at 0900): 1014.3 mb  
    
Winds    
Run of wind (mean over 24 hrs): 130.0 miles  
Mean daily wind speed: 7.0 mph  
Run of wind (cumulative): 4030.3 miles  
Highest Maximum Gust: 42 mph on 29th
No. of gusts of 50mph or more: 0   
Highest wind strength (at 0900): 26.5 mph on 30th
Mean wind strength (at 0900): 10.7 mph  
    
Winds from the Following Directions:    

N 3 NE 1 E 0 SE 1 S 4 SW 7 W 7 NW 7 Calm 1

Concrete     
Lowest Concrete Minimum: 5.8 C on 31st
Mean Concrete Minimum: 11.2 C  
    
Evaporation    
Piche 86.2 ml 
Pan Not available. Flooded owing to torrential rain on 25th. 
    
Days with:    
Thunder: 2   
Hail <5mm: 0   
Hail >/=5mm: 0   
Snow or snow & rain: 0   
Snow lying: 0   
Fog: 0   
Air Frost: 0   
Gales: 0   


All data © Pitsford Hall weather station.

The weather station publishes a full Monthly Weather Report (ISSN 1741-4733) which is distributed to libraries across Northamptonshire. This report comprises a full UK weather diary, reports of extreme weather events across the county, statistics from Pitsford Hall's affiliated stations across the county as well as news from the weather station itself. Individuals may download this report for £2 or take out an annual subscription for the paper-based report for £25. Click here for further details.