WEATHER REVIEW - January 2014

Headline:  A similar pattern to December 2013 – mild, windy and very wet. The wettest January locally since 1939.

January opened with a complex area of low pressure dominating the charts. The main centre of the low was located west of Ireland, but several weather fronts circulated about the central area, including discrete low pressure systems in their own right which often intensified to produce strong winds and spells of heavy rain. One of these moved up from the south-west on the 1st delivering 13.5mm of rain at Pitsford in 24 hours. In fact, this low pressure system remained in place for over a week giving some sizeable rainfall totals (8.6mm on the 3rd, 6.6mm on the 6th and over 5mm on the 4th and 8th). Most days saw wind speeds exceeded 30mph, and the 1st and 6th saw wind speeds reaching around 40mph. Apart from the 2nd, sunshine was in particular short supply. Although the main centre of the low started to move away to the north-east on the 7th into the 8th, another fast tracking low moved up from Biscay on the 8th into the 9th to give a last sting in the tail before a ridge built in from the west.

The ridge, which was relatively short-lived, brought clearer skies during the daytime, a consequence of which was some chilly nights and daytime temperatures which were slow to recover. Up until this point, hardly any air frosts had been recorded this winter at Pitsford, but following a particularly sunny day on the 11th and a clear night, temperatures fell to -1.4C on the morning of the 12th and again to -0.5C the following morning. It wasn’t completely dry during this period though. An occlusion worked south-eastwards on the 10th into the 11th introducing outbreaks of rain (1.3mm at Pitsford).

The ridge pulled away eastwards late on the 12th with frontal systems introducing further spells of rain. Conditions became increasingly cyclonic across the UK. Initially, the country found itself under the influence of a small weak low and associated occlusion on the 13th and 14th, but gradually a more significant and deeper low pressure centre developed west of Ireland which drove frontal systems and outbreaks of rain right across the country. Following the arrival of a warm front associated with this development on the 15th, temperatures recovered reaching a daytime maximum of 10.6C. However, once the trailing cold front followed through overnight, temperatures dropped markedly to around 0.5C. Some prolonged outbreaks of rain accompanied these fronts.

The low began to fill gradually on the 16th, but conditions remained cyclonic over the next few days with weakening occlusions stagnating across the country. Mainly light showers were recorded across the county, separated by longer spells of sunshine and with wind speeds generally easing. It finally dried out on the 19th with a couple of fine and mostly sunny days. Clearer skies though led to a brief cold snap on the 20th into the 21st as temperatures dropped below freezing.

Pressure then deepened south of Iceland on the 21st driving a new wave of frontal systems in off the Atlantic. Although these frontal systems were relatively weak, high pressure over Scandinavia formed a barrier to their eastward migration. The result was several fairly damp and drizzly days with early morning mist and fog. The low over Iceland deepened dramatically between the 24th and 25th and drove a significant line squall southwards through the county during the afternoon of the 25th. The squall was accompanied by hail and thunder and recorded gusts of up to 60mph causing some structural damage to properties in Cottesbrooke. The centre of this low then worked slowly south-eastwards towards the UK over the next few days, remaining fairly stationary across the country and filling slowly. As the low cleared the country southwards on the 29th into the 30th it drew in much colder air from the continent.

Analysis chart for midnight on 5th into 6th January revealing the large low pressure system which dominated the weather during the first week of January.  In fact, for much of the month the picture was not dissimilar with one Atlantic low after another moving in across the country.

Air Temperatures    
The Highest Maximum: 12.2 C on 5th
The Lowest Maximum: 4.3 C on 30th
The Highest Minimum: 6.9 C on 7th
The Lowest Minimum: -2.0 C on 21st
The Mean Maximum: 8.5 C  
The Mean Minimum: 2.4 C  
The Overall Mean: 5.5 C  
Difference from the Monthly Mean: 0.8 C  
    
Solar Radiation    
Maximum (at 0900): 120.0 W/m^2 on 11th
Mean (at 0900): 20.5 W/m^2  
    
Relative Humidity:    
Highest Relative Humidity (at 0900): 100.0 % on 21st
Lowest Relative Humidity (at 0900): 74.9 % on 3rd
Mean Relative Humidity (at 0900): 92.8 %  
    
Dew Point:    
The Highest Dew Point (0900): 8.2 C on 15th
The Lowest Dew Point (at 0900): -0.8 C on 20th
The Mean Dew Point (at 0900): 3.6 C  
    
Rainfall:    
Total: 112.8 mm  
Percentage of the Monthly Mean: 203.9 %  
Duration: 95.1 hrs  
Highest 24 hour fall (0900 to 0900): 13.5 mm on 1st
Rain Days (>/=0.2mm): 27   
Wet Days (>/=1.0mm): 23   
    
Sunshine:    
Total Duration of Bright Sunshine: 36.5 hrs  
Sunniest day: 3.5 hrs on 17th
No. of days without sunshine: 11   
Percentage of the Monthly Mean: 74.5 %  
Cloud cover (mean at 0900): 5.1 oktas 63.8 %
    
Pressure (reduced to sea level):    
The Highest Pressure (at 0900): 1020.5 mb on 12th
The Lowest Pressure (at 0900): 982.0 mb on 28th
Mean Pressure (at 0900): 1001.4 mb  
    
Winds    
Run of wind (mean over 24 hrs): 167.0 miles  
Mean daily wind speed: 9.0 mph  
Run of wind (cumulative): 5177.6 miles  
Highest Maximum Gust: 60 mph on 25th
No. of gusts of 50mph or more: 1   
Highest wind strength (at 0900): 20.8 mph on 1st
Mean wind strength (at 0900): 9.9 mph  
    
Winds from the Following Directions:    

N 0 NE 1 E 2 SE 9 S 12 SW 5 W 2 NW 0 Calm 0
    
Concrete     
Lowest Concrete Minimum: -4.0 C on 21st
Mean Concrete Minimum: 2.1 C  
    
Evaporation    
Piche 38.3 ml  
    
Days with:    
Thunder: 1   
Hail <5mm: 1   
Hail >/=5mm: 0   
Snow or snow & rain: 1   
Snow lying: 0   
Fog: 2   
Air Frost: 4   
Duration of Air Frost: 5.3hrs
Gales: 0   

All data © Pitsford School weather station.

Click here to view the full climatological register for January 2014.

Click here to view the weather diary for January 2014.

Click here to view the full AWS weather record for January 2014.
Click here to view the statistical summary for 2014.

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 School'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.