Monthly Summary - January 2011

   After a quiet (anticyclonic) first few days of the month the first half was generally unsettled (cyclonic) with rainfall on every day and with two notable wet days as we had a steady SW'ly airflow. One of those days was very wet and quite violent. Then the second half of the month became dry and settled as high pressure (anticyclonic) became the dominant feature. However, the month was still slightly on the cool side.

   There was a little rain early on the 1st as a cold front pushed south from Scotland, but an area of high pressure (AHP) (1034 - 2nd) built behind it and established a N'ly flow. We had three successive air frosts and the 2nd only reached a high of 0.7°c under cloudy and dull skies and this was the case on the 3rd as the AHP (1030) sat over the UK.

   But the change came on the 4th and for the next 12-13 days our weather was decidedly wet and unsettled.

   An area of low pressure (ALP) (998) north of the UK pushed a cold front South on a W'ly flow on the 4th and with it 11.2mm of rain. The days were windy, cloudy and dull and with spells of rain, that whilst never excessive, were still the dominant feature of the weather.

   We then had some snowfall on the 7th as a warm front pushed south out of Scotland, but nothing of real note and not sufficient enough to provide a 'day of laying snow'. A little sleet on the 8th and further snow on the 9th, but rain was still the story as ALP still had control. The 9th felt cold and fresh and we had some sunny spells mixed in with the showers.

   The 10th was a day to forget with 31.0mm of rain which was heavy at times and came on an occlusion front from the SW. After a sunny afternoon on the 11th brought by a small ridge of high pressure the next few days were generally cloudy and dull with a little rain, this being due to the influence of the warm and moist SW'ly flow. The 13th brought the months warmest day at 10.3°c (50.5°F) - we had to wait to mid March last year to hit 10.0°c!

   But then came the 15th. The 14th had seen showers as we were still in that SW'ly flow and brought on a trough that moved east from Eire. But ALP (977) was racing across the Atlantic towards us and deepening as it approached - when it arrived the 15th was awful.

   48.7mm of rain and a maximum gust of 60mph was what we had to endure. The second wettest day to be recorded at this site and a new record for highest gust. With 0900-0900 rainfall readings it gave 68.1 mm during the 'rainfall event'. During 2010 no single day recorded 25.4 mm (1 inch) of rain or more and now by the middle of January we'd had the two!

   The 16th saw that rain continue as a complex ALP (966) North of the UK had its associated weather fronts move through our region in the early hours and the winds gusted upto 59 mph - but then it was clearer behind and brightened up p.m.

   But then a change commenced and all became quite dry and settled, but not necessarily brighter. The first 16 days had seen 140.1 mm of rain and has a whole the month had 142.6 mm, which quite demonstrates the change. We had suuny intervals from 1100Hrs on the 17th and the 18th and 20th were sunny days with the 19th a cloudy but bright day. We were in a fairly slack area but high pressure (1036) was building and establishing itself over the UK.

   The 20th whilst sunny was also cold in a ENE'ly wind and for the next few days we had a generally Nw'ly flow and now there was a nip in the air. The 18th - 22nd all saw air frosts, but the 21st was a 'day of fog' and the years first Ice day with a maximum temp' of -1.1°c (30°F). It was also the 21st when the AHP was at its highest and at 1042.8 MB a new record at this site.

   That AHP started to slip West into the Atlantic from the 23rd and on the 24th (now 1043) was sufficiently west of Eire to allow the wind (clockwise around AHP) to come down its Eastern side as that cool NW'ly. This was the cause of the several days of cool, cloudy and dull conditions. Light rain on the 25th came from a weak front circulating around that AHP.

   Snow in the early hours of the 28th saw a very slight dusting and this was repeated on the 30th which had a weakening frontolytic cold front moving clockwise around the AHP (1027).

   The last four days of the month all saw air frosts with the months coldest temp' of -6.9°c (19.6°F) coming on the 29th. The month then closed with a second day of fog.

   Now the ridge of high pressure was eroding from the Atlantic and bringing ALP (975) with a double frontal structure wrapped around it and that was strengthening - but that was for February!

   The Mean Temperature for the month was 2.41°c+     - the Mean Max' was 5.03°c and the Mean Min' -0.21°c.

   We had 15 Air Frosts in the month and Grass frosts totalled 22.

   The 30 cm soil temp ranged from 0.9°c on the 3-4th to 5.6°c on the 16th with a monthly mean of 2.93°c


   * January 2011 rainfall was 87.48% of the January average for 08/09/10

   * January 2011 was 2.06°c warmer than January 2010   --   0.76°c colder than 2009 +

   * January saw 18 days of rain, of which 13 were wet days.

  * The 3 month mean for November/December/January 2010-11 is              TEMP'    1.42°c          -          RAIN    295.00 mm

* November/December/January 2009-10 was TEMP'    3.02°c - RAIN    446.80 mm

* November/December/January 2008-09 was TEMP'    - RAIN    402.50 mm

* November/December/January 2007-08 was TEMP'    - RAIN    447.90 mm

   + Met office figures for January show that NW England/N. Wales had a mean temp' of 2.9°c, some -0.6°c colder than the reference period 1971-2000 (-0.2°c colder than reference period 1961-90)


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