PITSFORD HALL WEATHER STATION NORTHAMPTON, UNITED KINGDOM MONTHLY WEATHER REPORT - DECEMBER 2004 Headline: Grey but dry for the first half, turning increasingly unsettled later. A cold and snow-less Christmas period. A dry start to the month. Although a front edged southwards through the first three days, it produced little more than trace amounts of rainfall at Pitsford. Temperatures were about average, turning colder on the 3rd and 4th due to the presence of persistent fog. As winds backed more south-westerly on the 4th temperatures began to recover reaching 10.5C on the 5th, although a second weak front brought plenty of cloud and drizzly spells. In fact, the 5 days between the 4th and 8th, saw no recorded sunshine at Pitsford. High pressure over continental Europe maintained a dry theme from 10th through to the 13th. The wind turned east or south-easterly on the 12th feeding in cold air off the continent. It became rather grey and misty once again. With the exception of a few hours of sunshine on the 9th, the total recorded sunshine for the month up until the 16th was a pitiful 13.3 hrs. By the 14th the wind had turned westerly bringing an improvement in the temperatures. The milder air also brought with it spells of rain. A discrete area of low pressure tracked through the county on the 17th bringing strong winds gusting to 48mph at Pitsford. Showers on the 18th gave way to rain in many areas on the 19th although much of the county escaped dry. As high pressure developed on the 20th, clear skies overnight brought a sharp frost. The air minimum at Pitsford fell to -3.6C whilst a ground frost of -8.1C was also recorded. Over the next few days it turned milder with an increasingly strong westerly airflow. By the 23rd daytime temperatures had become positively balmy for the time of year with highs of 12.7C with an exceptionally mild night to follow (8.6C). A cold front worked south-eastwards in the run up to the festive period. Further fronts moving southwards brought snow showers to many western areas on Christmas Day, although the county was not to experience a white Christmas. However, it was particularly cold with highs of just 3.5C falling close to freezing overnight. The cold weather continued into Boxing Day which was also bright with some 6.1hrs of recorded sunshine. As the month came to a close a succession of Atlantic fronts and westerly winds maintained a mild, wet and occasionally windy theme. The 27th saw 7.9mm falling over nearly 5 hrs. The highest recorded temperature came near the end of the month with 12.7C being recorded on the 30th . Despite the mild conditions by day, clear spells overnight still produced some frosts, moreso early on in the period. Air Temperatures The Highest Maximum: 12.7C on 23rd & 30th The Lowest Maximum: 3.0C on 20th The Highest Minimum: 8.6C on 23rd The Lowest Minimum: -3.6C on 20th The Mean Maximum: 8.2C The Mean Minimum: 2.1C The Overall Mean: 5.2C Difference from the Monthly Mean: -0.3C Relative Humidity: Highest Relative Humidity (at obs): 100.0% on 3rd, 4th, 8th & 21st Lowest Relative Humidity (at obs): 72.2% on 19th Mean Relative Humidity (at obs): 93.3% Dew Point: The Highest Dew Point (at obs): 10.3C on 31st The Lowest Dew Point (at obs): -2.6C on 19th The Mean Dew Point (at obs): 3.8C Rainfall: Total: 19.6mm Difference from the Monthly Mean: 31.2% Duration: 22.7hrs Highest 24 hour fall (obs to obs): 7.9mm on 27th Rain Days (>/=0.2mm): 9 Wet Days (>/=1.0mm): 6 Sunshine: Total Duration of Bright Sunshine: 58.5hrs Sunniest day: 6.7hrs on 28th Days without sunshine: 11 Cloud cover (mean at obs): 5.9oktas (73.8%) Pressure (reduced to sea level): The Highest Pressure: 1031.7mb on 8th The Lowest Pressure: 991.0mb on 17th Mean Pressure (recorded at obs): 1018.0mb Winds Run of wind (mean over 24 hrs): 125.1miles Mean daily wind speed: 6.8mph Highest mean daily wind speed: 13.9mph on 14th Run of wind (to date): 3877.3miles Highest Maximum Gust: 48mph on 17th Highest wind strength (at obs): 13.8mph on 15th Mean wind strength (at obs): 7.0mph Winds from the Following Directions: N 0 NE 1 E 3 SE 1 S 14 SW 2 W 4 NW 5 Calm 1 Ground Temperatures: Lowest Grass Minimum: -8.2C on 26th Mean Grass Minimum: -2.0C Lowest Concrete Minimum: -5.2C on 26th & 27th Mean Concrete Minimum: -0.3C Lowest Bare Earth Minimum: -2.2C on 27th Mean Bare Earth Minimum: 1.6C Soil/Earth Temperatures: Surface mean: 4.6C 5cm mean: 4.6C 10cm mean: 5.0C 20cm mean: 5.5C 30cm mean: 5.7C 40cm mean: 5.7C 50cm mean: 6.3C 100cm mean: 7.4C Days with: Thunder: 0 Hail less than 0.5mm: 0 Hail greater than/equal to 0.5mm: 0 Snow or snow & rain: 0 Fog 4 Air Frost: 8 Duration of Air Frost: 54.0hrs Ground Frost: 21 Gales: 0 Total Evaporation (tank) 9.71mm