Monthly Weather Review - Pitsford Hall

Headline: The warmest September since 1985 and the second warmest since 1949. Sunshine recorded above average.

September began with low pressure dominating the weather across the UK. On the 1st a depression lay off the north-west coast of Scotland whilst a frontal wave straddling central parts of the British Isles. Areas of rain moved eastwards delivering small amounts at Pitsford. The main low moved eastwards past the north of Scotland over the next few days to allow a ridge of high pressure to build up from the south. A spell of dry weather followed and with a good south-westerly airflow daytime maxima at Pitsford climbed to 27.0C on the 6th. However, a weak warm front did move across the region on the 5th and whilst this gave a fair amount of cloud and rain in places, its passage was hardly noticeable across the county.

High pressure had become established west of Ireland on the 7th and over the next few days this drifted slowly eastwards across the British Isles producing a fine and settled spell of weather. Winds remained generally light although overnight clear skies allowed temperatures to fall away quite smartly. Lows overnight leading to the 8th dropped to around 7.5C with subsequent daytime maxima struggling to top 20C. There were some misty early mornings with some particularly dense fog recorded on the 10th. In fact, many inland areas became very warm on the 10th and at Pitsford temperatures rose to 26.5C.

A warm and southerly airflow was introduced on the 11th forcing temperatures at Pitsford to climb to 29.3C during the afternoon making this the warmest September day since 1921. The warmth triggered some showers, but amounts were slight at Pitsford compared with elsewhere until the 13th when a thunderstorm delivered 7.7mm of rain in just over 3 hours. On most mornings visibility was quite poor with mist recorded on several occasions.

The UK lay beneath a col on the 15th and the next few days saw a fairly uneventful spell of weather across the county. A gentle northerly airflow saw temperatures fall away and mist continued to plague many areas on most mornings. Frontal systems pushed eastwards on the 17th and 18th, but these generally broke up through the county delivering only a token amount of rain.

The period from the 21st to the end of the month was largely unsettled. The remnants of hurricane Gordon began to push into the south-west of the UK on the 21st, finally reaching the county on the 22nd delivering some 15.3mm rain over the course of 5 hours. Fortunately, the strong winds which were anticipated never materialised. The residual low of Gordon remained to the west of Ireland over the next few days gradually filling, kept in check by an extensive high over continental Europe.

High pressure built up from the south on the 26th ahead of the remnants of a second hurricane, Helene, which pushed a fairly vigorous frontal systems eastwards on the 28th. This system remained across the county on the 29th delivering 6.0mm rain in the space of 3 hours. As the month came to a close on the 30th, low pressure remained the dominant influence with a further 7.3mm of rain recorded.

Overall, this was the warmest September in Northampton since 1985 and the second warmest since 1949.


Air Temperatures    
The Highest Maximum:  29.3C on 11th
The Lowest Maximum:  17.4C on 22nd
The Highest Minimum:  16.3C on 14th
The Lowest Minimum:  7.5C on 8th
The Mean Maximum:  22.2C  
The Mean Minimum:   13.0C  
The Overall Mean:   17.6C  
Difference from the Monthly Mean: +3.6C  
    
Relative Humidity:    
Highest Relative Humidity (at 0900): 99.0% on 24th
Lowest Relative Humidity (at 0900): 66.5% on 21st
Mean Relative Humidity (at 0900): 85.4%  
    
Dew Point:    
The Highest Dew Point (0900):  18.2C on 14th
The Lowest Dew Point (at 0900): 9.9C on 8th
The Mean Dew Point (at 0900): 14.3C  
    
Rainfall:    
Total:    49.5 mm  
Difference from the Monthly Mean: 87.3 %  
Duration:    22.9 hrs  
Highest 24 hour fall (0900 to 0900): 15.3mm on 22nd
Rain Days (>/=0.2mm):  13   
Wet Days (>/=1.0mm):  9   
    
Sunshine:    
Total Duration of Bright Sunshine: 151.9hrs  
Sunniest day:   9.4hrs on 3rd
No. of days without sunshine:  2   
Difference from the Monthly Mean: 114.7%  
Cloud cover (mean at 0900):  5.8oktas 72.5%
    
Pressure (reduced to sea level):    
The Highest Pressure:  1032.7mb on 8th
The Lowest Pressure:  1001.9mb on 14th
Mean Pressure (recorded at 0900): 1012.9mb  
    
Winds    
Run of wind (mean over 24 hrs): 82.6miles  
Mean daily wind speed:  4.5mph 
Highest mean daily wind speed: 9.7mph on 2nd 
Run of wind (cumulative):  2478.9miles  
Highest Maximum Gust:  34mph on 2nd
No. of gusts of 50mph or more: 0   
Highest wind strength (at 0900): 11.5mph on 15th
Mean wind strength (at 0900):  5.2mph  
    
Winds from the Following Directions:    

N 4 NE 1 E 2 SE 3 S 9 SW 6 W 2 NW 1 Calm 2   
    
Ground Temperatures:     
Lowest Grass Minimum:  3.9C on 8th
Mean Grass Minimum:  10.2C  
Lowest Concrete Minimum:  6.5C on 8th
Mean Concrete Minimum:  11.8C  
Lowest Bare Earth Minimum:  5.9C on 8th
Mean Bare Earth Minimum:  11.7C  
    
Soil/Earth Temperatures:     
Surface mean:   16.5C  
5cm mean:   15.9C  
10cm mean:   16.2C  
20cm mean:   16.5C  
30cm mean:   16.9C  
40cm mean:   16.9C  
50cm mean:   17.1C  
100cm mean:   16.6C  
    
    
Days with:    
Thunder:    1   
Hail <5mm:   0   
Hail >/=5mm:   0   
Snow or snow & rain:  0   
Fog:    2   
Air Frost:    0   
Ground Frost:   0   
    
Total (Tank) Evaporation:  67.57mm  
% Rainfall to Evaporation:  73.3%

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.