Monthly Weather Review - Pitsford Hall

Headline: Mainly cyclonic with above average rainfall. Significant rainfall on the 20th triggering floods across south Northants.

The month began with low pressure across the British Isles centred south-west of Ireland. This low moved only very slowly north-eastwards driving active frontal systems across the region. Some heavy showers were recorded in Pitsford, particularly on the 1st, 3rd and 5th, and for the second time within a month the village of Stoke Goldingston on the county border with Buckinghamshire was flooded. The village saw some 60mm of rain in the space of 24 hours on the 2nd. The low which dominated the first five days of July finally pulled away on the 5th only to be quickly followed by a fairly active low and some fairly strong westerly winds on the 6th.

High pressure began building across the southern half of the UK on the 7th and with it came a fine and settled day across the county. Some 12.7 hrs of sunshine were recorded at Pitsford on a reasonably warm day with light westerly winds. However, the strength of the high was insufficient to prevent a progression of frontal systems across the region on the 8th and 9th bringing further showers overnight. By the 10th, low pressure which had remained present over Scandinavia throughout this period, began to extend an influence further south. However, the county was fortunate to escape with another fine day with some good sunny spells, cloud only began to build significantly during the evening. By the 11th, the high was regaining control across the south and the county enjoyed another fine settled day, although somewhat cooler with winds coming in from the north or north-west.

Over the next few days frontal systems worked across the UK tied into low pressure developing south-west of Iceland. The low then moved steadily eastwards becoming centred over Scotland on the 14th. Rainfall totals across the county through this period were generally slight and most afternoons saw some glimmers of sunshine. Winds remained light and from the south-west, freshening on the 14th as the low drew closer.

A new low moved in off the Atlantic on the 16th bringing frequent showers across the county on the 17th and 18th. By the 20th yet another area of low pressure had developed over northern France and through the day this low moved steadily northwards driving wind and rain across the southern half of

Britain

. The rainfall tied into this low was significant across many areas. 26.6mm was recorded at Pitsford in the 24 hour period leading up to 0900GMT on the 21^st, most of this falling in several torrential and thundery downpours. Villages in the south of the county were hit by flooding, particularly Helmdon, Syresham and Silverstone. However, the county was fortunate not to experience the scale of flooding seen in Gloucestershire where the town of Tewkesbury was cut off by floodwater and over 300 000 homes were left without clean drinking water.

The low continued to work northwards across

Britain

on the 21st with associated frontal systems continuing to drive spells of rain across the county. However, sunshine finally broke through during the afternoon and the 22nd also saw some warm sunshine and an opportunity for much of the county to dry out. Unfortunately, the dry weather was short-lived as the next Atlantic low worked across the southern half of Britain on the 23rd driving some early showers across the county. As this low worked towards the Netherlands on the 24th a ridge of high pressure built in across the

from the south-west. The result was a reasonably warm day across the county with some good sunshine. However, the high was no match for a deep low developing south of Iceland which drove some active frontal systems eastwards on the 25th and again on the 26th. Once again some heavy spells of rain were recorded across the county, with torrential downpours in places. 12.6mm fell in a little over 3 hours at Pitsford during the morning, clearing largely to sunshine through the afternoon.

A frontal wave was left on the trailing wake of the storms of the 26th and this introduced further rain on the 28th as it developed into another discrete low pressure centre over the southern half of the UK. However, the 4.1mm that were recorded at Pitsford was the last rain event in what amounted to another very wet month. High pressure to the west of Ireland would gradually extend its influence across the whole of the UK ensuring that the month would come to a close with a better approximation of summer weather.

With the frequency of cloud and rain across the county, temperatures throughout July remained modest. By coincidence the warmest day occurred on the 19th (23.9C) the same day as the warmest day ever recorded in July last year. However, temperatures were well short of the 35.5C which was recorded on this occasion.

Air Temperatures    
The Highest Maximum:   23.9C on 19th
The Lowest Maximum:   14.6C on 20th
The Highest Minimum:   15.5C on 16th
The Lowest Minimum:   8.5C on 8th & 30th
The Mean Maximum:   19.6C  
The Mean Minimum:   11.6C  
The Overall Mean:   15.6C  
Difference from the Monthly Mean: -1.7C  
    
Black Bulb    
Maximum (at 0900):   34.3C on 19th
Mean (at 0900):    21.6C  
    
Relative Humidity:    
Highest Relative Humidity (at 0900): 97.7% on 21st
Lowest Relative Humidity (at 0900): 64.2% on 30th
Mean Relative Humidity (at 0900): 79.5%  
    
Dew Point:    
The Highest Dew Point (0900):  14.6C on 16th
The Lowest Dew Point (at 0900): 7.9C on 30th
The Mean Dew Point (at 0900):  11.7C  
    
Rainfall:    
Total:     77.8mm  
Difference from the Monthly Mean: 162.4%  
Duration:    51.1hrs  
Highest 24 hour fall (0900 to 0900): 26.6mm on 20th
Rain Days (>/=0.2mm):   18   
Wet Days (>/=1.0mm):   14   
    
Sunshine:    
Total Duration of Bright Sunshine: 200.7hrs  
Sunniest day:    13.9hrs on 31st
No. of days without sunshine:  3   
Difference from the Monthly Mean: 113.5%  
Cloud cover (mean at 0900):  6.5oktas (81.3%)
    
Pressure (reduced to sea level):    
The Highest Pressure:   1021.4mb on 31st
The Lowest Pressure:   998.3mb on 3rd
Mean Pressure (recorded at 0900): 1010.8mb  
    
Winds    
Run of wind (mean over 24 hrs): 103.0miles  
Mean daily wind speed:   5.6mph  
Run of wind (cumulative):  3191.5miles  
Highest Maximum Gust:   35mph on 20th
No. of gusts of 50mph or more:  0   
Highest wind strength (at 0900): 18.4mph on 30th
Mean wind strength (at 0900):  7.8mph  
    
Winds from the Following Directions:    

N 3 NE 1 E 1 SE 1 S 5 SW 6 W 6 NW 5 Calm 5   
    
Concrete     
Lowest Concrete Minimum:  8.0C on 8th
Mean Concrete Minimum:  11.7C  
    
 
Days with:    
Thunder:    1   
Hail <5mm:    0   
Hail >/=5mm:    0   
Snow or snow & rain:   0   
Fog:     0   
Air Frost:    0   
Gales:     0   
    
Evaporation    
Pan     74.96mm  

All data © Pitsford Hall weather station

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.