PITSFORD HALL WEATHER STATION
NORTHAMPTON, UNITED KINGDOM

MONTHLY WEATHER REPORT - JULY 2002


Headline: The wettest July in Northampton since 1988. Unsettled 
start then becoming warm and dry. Hot final week with thundery 
breakdown and torrential rain.

Frontal systems which had arrived off the Atlantic at the end of 
June continued to influence the weather across the county for the 
first week and a half. Rain fell on most days with the 8th and 9th 
being particularly wet with 12.3mm and 20.4mm respectively being 
recorded. It was also relatively cool, although daytime maxima began 
to recover in the second week. Although thunder was reported 
frequently across England and Wales, none was noted at Pitsford Hall.

A ridge of high pressure began to extend across the region during the 
third week. It was mainly dry with good spells of sunshine. 
Temperatures continued to improve and it became very warm with daytime 
maxima surpassing 25C on the 15th. 

During the fourth week a discrete area of low pressure tracked 
eastwards. This brought heavy showers to many parts of the Midlands; 
however, the county escaped with modest amounts, less than 2mm on the 
19th. Apart from some cool nights on the 21st and 22nd, daytime 
temperatures remained mostly in the low 20's. Winds remained 
mostly light.

The period from the 26th onwards saw a significant hike in temperatures 
peaking at 30.7C on the 29th. The heat triggered thunderstorms with 
some torrential downpours. 26.7mm fell in a just over 4 hours at 
Pitsford Hall, reaching at peak rate of 56.7mm per hour just 
before 1800hrs GMT. Flooding was reported in Wellingborough and 
tens of thousands of pounds worth of damage was caused to shops 
in Market Harborough when the river Welland burst its banks. Although 
rainfall totals in Northamptonshire were notable, many other areas 
caught more than a month's rainfall in the same period. Further 
heavy showers occurred on the 31st. Bicester, just across the county 
boundary, caught 52mm although a mere 1.1mm fell at Pitsford.


Climatological & Agromet Statistics - July 2002


Air Temperatures				
The Highest Maximum: 30.7C on 29th
The Lowest Maximum: 15.7C on 1st
The Highest Minimum: 17.6C on 30th
The Lowest Minimum: 8.0C on 10th

The Mean Maximum: 21.5C
The Mean Minimum: 11.8C
The Overall Mean: 16.7C
Difference from the Monthly Mean: -0.2C
				
Relative Humidity:				
Highest Relative Humidity (at 0900): 97.8% on 9th
Lowest Relative Humidity (at 0900): 57.7%n on 13th
Mean Relative Humidity (at 0900): 79.2%
    
Dew Point:				
The Highest Dew Point (at 0900): 18.4C on 30th
The Lowest Dew Point (at 0900): 9.1C on 2nd
The Mean Dew Point (at 0900): 13.1C
				
Rainfall:				
Total: 87.6mm
Difference from the Monthly Mean: 182.9%
Duration: 41.9hrs
Highest 24-hour fall (from 0900): 26.7mm on 30th
Rain Days (>/=0.2mm): 14
Wet Days (>/=1.0mm): 13
Lowest pH: 5.91 on 5th
			
Sunshine:				
Total Duration of Bright Sunshine: 151.9hrs
Sunniest day: 12.2 hrs on 13th
Sunless days: 0
Cloud cover (mean at 0900): 6.3 oktas (78.8%)
				
Pressure (reduced to sea level):				
The Highest Pressure: 1026.9mb on 14th XXXXXXXX
The Lowest Pressure: 996.5mb on 3rd XXXXXXXXX
Mean Pressure (recorded at 0900): 1013.8mb
		
Winds:				
Run of wind (mean over 24 hrs): 93.1 miles
Mean daily wind speed: 5.0mph
Highest 24-hour Wind Speed: 11.1mph on 7th
Run of wind (to date): 2885.0 miles
Highest Maximum Gust: 27mph on 3rd
Highest wind strength (at 0900): 16.1mph on 4th
Mean wind strength (at 0900): 7.1mph
		
Winds from the Following Directions:				
N 3 NE 2, E 1, SE 2, S 8, SW 4, W 1, NW 8, Calm 2
	
Days with:				
Thunder: 2: 9th & 30th
Hail less than 0.5cm: 0
Hail greater than/equal to 0.5cm: 0   
Snow or snow & rain: 0
Snow lying: 0
Fog: 0
Air Frost: 0
Duration of Air Frost: 0.0hrs
Ground Frost: 0


Evaporation: 

Total evaporation (tank): 88.76mm

					
Ground Temperatures:			 	
Lowest Grass Minimum: 5.6C on 22nd
Mean Grass Minimum: 10.2C
Lowest Concrete Minimum: 7.6C on 10th
Mean Concrete Minimum: 11.2C
Lowest Bare Earth Minimum: 8.1C on 22nd
Mean Bare Earth Minimum: 11.8C
				
Soil/Earth Temperatures:		 		
Surface mean: 18.6C
5cm mean: 17.1C
10cm mean: 17.3C
20cm mean: 17.2C
30cm mean: 17.3C
40cm mean: 17.2C
50cm mean: 17.3C
100cm mean: 15.9C
	
Climatological observations made at 0900 UTC.  Averages refer to the period 1971-2000.


All data © Northamptonshire Grammar School.