WEATHER REVIEW - May 2006

Headline: Very wet with more than one and half times the average rainfall. A warm start, but turning progressively cooler as the month proceeded.

May opened with the county under the influence of low pressure centred to the north-west of the UK. There were showers separated by some good sunny spells. Pressure than began to build across the region giving a generally settled spell of weather with temperatures showing a marked improvement rising from a high of just 12.6C on the 1st to 26.8C on the 4th which turned out to be the warmest day of the month; temperatures thereafter bucked the seasonal trend and fell progressively throughout the rest of the month.

The weather became unsettled once more from the 6th as a depression worked across the southern half of the UK. There were spells of rain across the county. The 8th was exceptionally wet with 10.7mm of rain falling in just under 6hrs. This rain was associated with a frontal system that was fairly stationary, particularly over eastern counties where even higher totals were recorded.

Pressure recovered briefly on the 10th bringing a spell of dry settled weather. The wind was light, northerly at first then backing more south-westerly. The 10th itself recorded some 12.7 hrs of sunshine with highs breaking through the 20C mark. In fact temperatures remained warm until the 12th, when 23.6C was recorded – the last occasion temperatures would exceed 20C during the month. In fact the warmth on the 12th triggered some thunderstorms and a fair amount of rain, 6.6mm in just under 5 hrs. Mist and fog would then plague the county for the next couple of mornings.

The marked cooling trend then began on the 13th. It also turned unsettled with varying amounts of rainfall being recorded on every day until the end of the month. The unsettled weather was particularly marked from the 17th. A train of Atlantic depressions brought spells of heavy rain, notably 9.1mm on the 19th and 8.9mm on the 21st, although several days also falls exceeding 5mm. The wind, which for much of the month so far had been fairly light, also picked up to a fresh south or south-westerly reached gusts of 35mph on the 19th. Daytime temperatures were cool for the time of year with highs generally not reaching 15C.

From the 24th onwards the wind began to fall light, although weather fronts continued to feed in spells of rain. A further 9.1mm was recorded on the 25th. In the closing days of May pressure began to build in from the west, although eastern areas and the county included continued to fall victim to heavy showers featuring some hail on the 29th. From the 28th the wind had swung round from the south-west to become quite a cool northerly. Overnight lows on the 30th and 31st brought with them the risk of some ground frost, although the lowest grass minimum at Pitsford on the morning of the 31st remained just above freezing (0.9C).

Overall, this was Northampton’s wettest May since 2000 (97.3mm) and the second wettest since May 1997 (107.2mm) with more than one and half times the monthly average falling over the town.  The month was the first to see above average rainfall since September 2005.  


Air Temperatures    
The Highest Maximum:   26.8C on 4th
The Lowest Maximum:   12.6C on 1st
The Highest Minimum:   12.6C on 27th
The Lowest Minimum:   2.5C on 2nd
The Mean Maximum:   17.1C  
The Mean Minimum:   8.4C  
The Overall Mean:   12.8C  
Difference from the Monthly Mean: +0.3C  
    
Relative Humidity:    
Highest Relative Humidity (at obs): 95.4% on 7th
Lowest Relative Humidity (at obs): 44.6% on 12th
Mean Relative Humidity (at obs): 78.2%  
    
Dew Point:    
The Highest Dew Point (at obs):  15.0C on 4th
The Lowest Dew Point (at obs):  4.5C on 31st
The Mean Dew Point (at obs):  9.6C  
    
Rainfall:    
Total:     80.9mm  
Difference from the Monthly Mean: 162.4%  
Duration:    59.8hrs  
Highest 24 hour fall (obs to obs): 10.7mm on 8th
Rain Days (>/=0.2mm):   19   
Wet Days (>/=1.0mm):   16   
    
Sunshine:    
Total Duration of Bright Sunshine: 177.7hrs  
Sunniest day:    12.7hrs on 10th
Days without sunshine:   3
Cloud cover (mean at obs):  5.9oktas (73.8%)  
    
Pressure (reduced to sea level at 0900GMT):    
The Highest Pressure:   1026.3mb on 31st
The Lowest Pressure:   985.0mb on 22nd
Mean Pressure (recorded at obs): 1012.7mb  
    
Winds    
Run of wind (mean over 24 hrs): 104.6miles  
Mean daily wind speed:   5.7mph 
Highest mean daily wind speed:  11.1mph on 18th 
Run of wind (to date):   3242.0miles  
Highest Maximum Gust:   35mph on 19th & 29th
Highest wind strength (at obs):  16.1mph on 19th
Mean wind strength (at obs):  7.1mph  
    
Winds from the Following Directions:    

N 6 NE 0 E 3 SE 0 S 6 SW 7 W 4 NW 3 Calm 2   
    
Ground Temperatures:     
Lowest Grass Minimum:   -1.0C on 2nd
Mean Grass Minimum:   5.8C  
Lowest Concrete Minimum:  5.4C on 31st
Mean Concrete Minimum:  9.2C  
Lowest Bare Earth Minimum:  3.9C on 2nd
Mean Bare Earth Minimum:  8.8C  
    
Soil/Earth Temperatures:     
Surface mean:    13.9C  
5cm mean:    12.9C  
10cm mean:    13.1C  
20cm mean:    13.3C  
30cm mean:    13.7C  
40cm mean:    13.4C  
50cm mean:    13.6C  
100cm mean:    11.7C  
    
    
Days with:    
Thunder:    1   
Hail less than 0.5mm:   1   
Hail greater than/equal to 0.5mm: 0   
Snow or snow & rain:   0   
Fog     1
Ground Frost:    1 
Air Frost:    0
Gales:     0 
            
Total Evaporation (tank)  66.82mm   

All data © Pitsford Hall weather station.
Click here to view the full climatological register for May 2006. 
Click here to view the full AWS weather record for May 2006.
Click here to view the statistical summary for 2006.

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 subscribe to this report at a rate of £15 per year. Please contact the station for further information.