Monthly Weather Review - Pitsford Hall

Headline: Settled first half under the influence of a fairly stationary high. Unsettled in the second half with frequent outbreaks of rain.

April began with pressure fairly slack across the UK but with a ridge of high pressure building in from mainland Europe. However, over the next few days it was an anticyclone developing west of Ireland which was to extend its influence across the British Isles. For much of the first week this high would be centred over Ireland maintaining a run of north or north-westerly winds across the county. High pressure ensured several days of good sunshine with daytime highs typically rising to 7C, but falling sharply overnight under largely clear skies with air frost recorded on most nights. Between the 7th and the 9th, the high had positioned itself right on top of the UK and with very light winds overnight lows on the 7th and 8th fell to -4.5C.

Although its exact centre would vary, firstly pulling away to the west, then the south-west and finally to the south, this stationary high would maintain an influence on the county’s weather until at least the 17th. Its initial movement westwards allowed frontal systems to work southwards on the 11th and 12th introducing some outbreaks of light rain and as the pressure gradient steepened on the eastern flank of the high over the next few days, winds would pick up across the county to a good moderate north-westerly. This brought in air from a much warmer source and temperatures correspondingly rose, during the daytime especially towards a high of 15.8C on the 18th.

Low pressure south of Iceland which had been blocked by the protracted high over the UK finally made progress past the north-west of Scotland from the 18th onwards and frontal systems linked into this low drove somepulses of rain across Northamptonshire, although the heaviest rain on the 19th was associated with a second low which moved quickly up from the south-west. Accompanying the rain was a fairly strong south-westerly breeze.

A ridge of high pressure on the 21st made for a settled day with some good sunshine, something of a window in the weather which returned with further pulses of frontal rain on the 22nd. In fact, in the days that followed a complex system of low pressure developed west of the UK and the country became increasingly under its influence. Northamptonshire saw several wet days, although much of the rain tended to be showery in nature with some spells of sunshine in between the showers. No sooner had this low wound itself up on the 28th, than a second low approached from the south-west deepening as it moved towards the UK. This ensured that the month came to a very unsettled close.

Air Temperatures    
The Highest Maximum: 15.8 C on 18th
The Lowest Maximum: 5.0 C on 10th & 11th
The Highest Minimum: 8.5 C on 20th
The Lowest Minimum: -4.5 C on 7th & 8th
The Mean Maximum: 10.0 C  
The Mean Minimum: 2.5 C  
The Overall Mean: 6.3 C  
Difference from the Monthly Mean: -0.2 C  
    
Solar Radiation    
Maximum (at 0900): 584.0 W/m^2 on 27th
Mean (at 0900): 191.3 W/m^2  
    
Relative Humidity:    
Highest Relative Humidity (at 0900): 100.0 % on 23rd
Lowest Relative Humidity (at 0900): 60.9 % on 8th
Mean Relative Humidity (at 0900): 86.0 %  
    
Dew Point:    
The Highest Dew Point (0900): 10.5 C on 20th
The Lowest Dew Point (at 0900): -5.8 C on 8th
The Mean Dew Point (at 0900): 3.2 C  
    
Rainfall:    
Total: 29.9 mm  
Percentage of the Monthly Mean: 65.6 %  
Duration: 38.4 hrs  
Highest 24 hour fall (0900 to 0900): 6.0 mm on 24th
Rain Days (>/=0.2mm): 11   
Wet Days (>/=1.0mm): 9   
    
Sunshine:    
Total Duration of Bright Sunshine: 106.8 hrs  
Sunniest day: 8.3 hrs on 7th
No. of days without sunshine: 3   
Percentage of the Monthly Mean: 93.4 %  
Cloud cover (mean at 0900): 5.6 oktas 70 %
    
Pressure (reduced to sea level):    
The Highest Pressure (at 0900): 1036.3 mb on 7th
The Lowest Pressure (at 0900): 983.3 mb on 31st
Mean Pressure (at 0900): 1017.1 mb  
    
Winds    
Run of wind (mean over 24 hrs): 136.2 miles  
Mean daily wind speed: 7.4 mph  
Run of wind (cumulative): 4221.5 miles  
Highest Maximum Gust: 41 mph on 31st
No. of gusts of 50mph or more: 0   
Highest wind strength (at 0900): 18.4 mph on 22nd
Mean wind strength (at 0900): 7.5 mph  
    
Winds from the Following Directions:    

N 3 NE 5 E 0 SE 3 S 8 SW 4 W 3 NW 5 Calm 0
    
Concrete     
Lowest Concrete Minimum: -5.7 C on 7th
Mean Concrete Minimum: 2.0 C  
    
Days with:    
Thunder: 0   
Hail <5mm: 1   
Hail >/=5mm: 0   
Snow or snow & rain: 0   
Snow lying: 0   
Fog: 0   
Air Frost: 8
Duration of Air Frost: 40.0 hrs   
Gales: 0   
    
Evaporation (#2)    
Pan 31.69 mm 
Piche 61.5 ml  


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.