Monthly Weather Review - Pitsford Hall

Headline: Mostly dry for the first fortnight but then becoming increasingly unsettled and autumnal. A tornado was reported in Northampton on the 24th.

September began with high pressure to the south-west but with much of the UK coming under the influence of an area of low pressure tracking eastwards from Iceland. Although the 1st was dry across the county, frontal systems working south-eastwards on the 2nd introduced rain and a fairly brisk north-westerly wind. In the wake of this frontal system high pressure gained control over much of the country introducing a fine and settled spell of weather right through to the 9th. Despite the persistent albeit light north-westerly breeze, temperatures remained fairly respectable for the start of September with highs typically reaching the high teens or low twenties and staying reasonably mild at night.

By the 9th an area of low pressure had started to circulate around the edge of the high and on the 10th frontal systems moved southwards across the North Sea introducing a fair amount of cloud across the county although rainfall amounts were only recorded as trace at Pitsford. With the centre of the low close-by to the north-east on the 10th winds picked up to a fairly brisk north-westerly with gusts reaching 35mph at Pitsford. The high regained control quickly though over the next few days maintaining the mainly dry spell right through to the 16th. However, the persistent anticyclone across the UK was subject to one or two invasions by weak frontal systems most notably on the 14th as a deep low developed over Iceland. However, little more than trace rainfall amounts and cloud were recorded at Pitsford.

On the 16th high pressure had pretty much retreated southwards to continental Europe as another deep low tracked past the north of Scotland driving frontal systems and a fairly brisk south or south-westerly airflow across the county. Over the next few days the low assumed a position over Scandinavia with frontal systems working southwards driving spells of rain through Northampton. High pressure west of

Ireland

did try to squeeze the influence of this low eastwards away from British shores, but across the county the weather remained mainly cyclonic with rain recorded on most days.

The rain became heavier on the 21st as a deep and rather extensive low developed over Iceland forcing the retreat of the high once again to mainland Europe. It became rather windy with gusts reaching 36mph on the 23rd and 39mph on the 24th when reports of a tornado damaging several homes in the Lumbertubs area of Northampton was confirmed by the Met Office. Some particularly heavy rain was recorded on the 25th across the county mostly tied into a thunderstorm which worked steadily southwards across the town. With the heavy rain came a notable change to more autumnal temperatures with highs on the 26th struggling to reach 12C at Pitsford with some particularly chilly nights and early mornings.

By the 26th high pressure west of Ireland was extending an influence eastwards across the UK, although the fairly brisk north-easterly airstream didn’t do much to lift the temperatures. Some rain was introduced from the south-east on the 27th and 28th. In fact, on the 28th it continued to rain for much of the day.

The month came to an end with a col developing across the UK with low pressure centred over Denmark and to the south-west. Some weak frontal systems tied into the Scandinavian low introduced cloud and trace amounts of rain on the 29th and 30th but otherwise it remained dry with light winds.


Air Temperatures: 
The Highest Maximum: 23.5 C on 6th
The Lowest Maximum: 12.0 C on 26th
The Highest Minimum: 13.8 C on 1st
The Lowest Minimum: 4.5 C on 18th
The Mean Maximum: 18.2 C  
The Mean Minimum: 10.0 C  
The Overall Mean: 14.1 C  
Difference from the Monthly Mean: +0.1 C  
    
Black Bulb:   
Maximum (at 0900): 26.0 C on 4th
Mean (at 0900): 17.8 C  
    
Relative Humidity:   
Highest Relative Humidity (at 0900): 96.8 % on 6th
Lowest Relative Humidity (at 0900): 60.9 % on 4th
Mean Relative Humidity (at 0900): 81.5 %  
    
Dew Point:    
The Highest Dew Point (0900): 13.8 C on 6th
The Lowest Dew Point (at 0900): 4.0 C on 18th
The Mean Dew Point (at 0900): 10.7 C  
    

Rainfall:    
Total: 38.2 mm  
Difference from the Monthly Mean: 67.4 %  
Duration: 33.3 hrs  
Highest 24 hour fall (0900 to 0900): 11.3 mm on 25th
Rain Days (>/=0.2mm): 10   
Wet Days (>/=1.0mm): 8   
    

Sunshine:    
Total Duration of Bright Sunshine: 152.1 hrs  
Sunniest day: 11.0 hrs on 3rd
No. of days without sunshine: 1   
Difference from the Monthly Mean: 114.9 %  
Cloud cover (mean at 0900): 4.8 oktas (60 %)
    
Pressure (reduced to sea level):    
The Highest Pressure: 1032.4 mb on 7th
The Lowest Pressure: 1003.6 mb on 24th
Mean Pressure (recorded at 0900): 1020.9 mb  
    
Winds    
Run of wind (mean over 24 hrs): 120.6 miles  
Mean daily wind speed: 6.5 mph  
Run of wind (cumulative): 3618.5 miles  
Highest Maximum Gust: 39 mph on 24th
No. of gusts of 50mph or more: 0   
Highest wind strength (at 0900): 23.1 mph on 27th
Mean wind strength (at 0900): 9.6 mph  
    
Winds from the Following Directions:    

N 10 NE 2 E 0 SE 0 S 4 SW 3 W 2 NW 6 Calm 3
    
Concrete     
Lowest Concrete Minimum: 1.1 C on 18th
Mean Concrete Minimum: 8.5 C  
    
Days with:    
Thunder: 1   
Hail <5mm: 0   
Hail >/=5mm: 0   
Snow or snow & rain: 0   
Fog: 0   
Air Frost: 0   
Gales: 0   
    
Evaporation
Pan: 74.04 mm  

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.