PITSFORD HALL WEATHER STATION NORTHAMPTON, UNITED KINGDOM MONTHLY WEATHER REPORT - DECEMBER 2002 Headline: Changeable for the first three weeks then becoming unseasonably mild, wet and dull as a run of Atlantic lows prevailed. December opened with a changeable few days. Although it was mild low pressure with associated frontal systems brought rain and showers across the county with winds mainly coming in from the south-west. From the 5th onwards high pressure began to build over Scandinavia and this brought a run of cold east or north-easterly winds which brought temperatures tumbling to a chill day at Pitsford on the 11th which recorded the lowest daytime maximum and minimum (1.4C and -1.5C respectively) as well as snow by evening. Temperatures then recovered and a wet period followed until the 17th associated with fronts tied into low pressure moving steadily north-eastwards from Biscay. Sunshine put in a brief appearance on the 11th and 14th, but most days until the 18th were very dull. The few days between the 17th and 19th saw the weather being influenced by high pressure which migrated south-eastwards from Scotland. Clear skies made for a good 6.3hrs of recorded sunshine on the 18th. The period from the 20th onwards saw an amelioration in the weather. In fact it became unseasonably mild as a succession of Atlantic lows brought in warm moist air from the south or south-west. The 21st was particularly wet with 21.4mm falling in 13 hours on the 21st. Thereafter there wasn't a single day in the remainder of December when no rain was recorded. The ground throughout much of the county quickly became saturated foreshadowing the flood warnings which were later to be issued by the Environment Agency in early January. Daytime maxima by the 24th had climbed to 13.0C with a particularly balmy night to follow with lows of 8.6C, far in excess of the norms expected at this time of year. Christmas 2002 was thus noted as one of the mildest for at least a decade. The copious snowfall which had been falling in the north-east United States a fortnight earlier failed to herald the white Christmas here that many wished for. As December came to a close there was no sign of the mild wet weather abating. Low pressure stalled over England and Wales in the final few days giving particularly wet days on the 28th (9.4mm) and 29th (10.6mm) with yet more rain waiting in the wings for the 31st (7.7mm) and the New Year period. The Environment Agency issues a floodwatch warning for the River Nene. STATISTICS Air Temperatures The Highest Maximum: 13.0C on 24th The Lowest Maximum: 1.4C on 11th The Highest Minimum: 8.6C on 24th & 27th The Lowest Minimum: -1.5C on 11th The Mean Maximum: 7.2C The Mean Minimum: 3.5C The Overall Mean: 5.4C Difference from the Monthly Mean: 0.1C Relative Humidity: Highest Relative Humidity (at 0900): 100.0% on 14th, 15th, 16th, 19th & 21st Lowest Relative Humidity (at 0900): 78.1% on 10th Mean Relative Humidity (at 0900): 94.5% Dew Point: The Highest Dew Point (at 0900): 10.8C on 1st The Lowest Dew Point (at 0900): -3.6C on 10th The Mean Dew Point (at 0900): 4.4C Rainfall: Total: 97.2mm Difference from the Monthly Mean: 154.5% Duration: 85.8hrs Highest 24 hour fall (from 0900): 21.4mm on 21st Rain Days (>/=0.2mm): 25 Wet Days (>/=1.0mm): 17 Lowest rainfall acidity (pH): 5.20 on 2nd Sunshine: Total Duration of Bright Sunshine: 31.4hrs Sunniest day: 6.6hrs on 9th Sunless days: 16 Cloud cover (mean at 0900): 7.4oktas (92.5%) Pressure (reduced to sea level): The Highest Pressure: 1032.7mb on 18th The Lowest Pressure: 985.7mb on 27th Mean Pressure (recorded at 0900): 1012.4mb Winds Run of wind (mean over 24 hrs): 140.2miles Mean daily wind speed: 7.6mph Run of wind: 4345.2miles Highest Maximum Gust: 41mph on 9th Highest wind strength (at 0900): 20.8mph on 12th Mean wind strength (at 0900): 10.3mph Winds from the Following Directions: N 5 NE 6 E 6 SE 3 S 7 SW 0 W 1 NW 2 Calm 1 Ground Temperatures: Lowest Grass Minimum: -4.0C on 18th Mean Grass Minimum: 1.6C Lowest Concrete Minimum: -2.5C on 11th Mean Concrete Minimum: 2.6C Lowest Bare Earth Minimum: -1.7C on 11th Mean Bare Earth Minimum: 2.6C Soil/Earth Temperatures: Surface mean: 5.2C 5cm mean: 4.9C 10cm mean: 5.4C 20cm mean: 5.9C 30cm mean: 6.0C 40cm mean: 6.1C 50cm mean: 6.6C 100cm mean: 7.3C Days with: Thunder: 0 Hail less than 0.5mm: 0 Hail greater than/equal to 0.5mm: 0 Snow or snow & rain: 1 Fog 4 Ground Frost: 10 Air Frost: 5 Duration of Air Frost: 25.0hrs Total Evaporation (tank): Not recorded - tank flooded on 21st. Reinstated on 1 January 2003.