Monthly Summary - November 2010

   Poor old November, a month that by now will surely have a totally negative image with most people. After last years deluge this November started off just like that of last year, ie: wet, but by the month's end it had brought on the early on-set of winter with a vengeance.

   The first half of the month was generally characterised by wind and rain brought on moist westerly Atlantic airflows and then after a cooler lull mid month we then saw the introduction of very cold Polar air brought on a N'ly airflow and with it the temperature plunged like a stone.

   Due to the heavy rainfall in the first part of the month followed by the very cold conditions, November has the distinction of being both a very wet and very cold month. However, it will probably be the cold and the snow for which it will be best remembered. A mean temperature of just 3.83°c (38.9°F) makes it the coldest since 1993 and certainly much colder than that of previous years. Add into that the last four days of the month being 'Days of laying snow' then November once again packed a punch.

   November also marks the end of Autumn and the days of snow at its end may make people forget that the season started with possibly our best bit of Summer!

   The month started with a succession of bad days with wind and rain the main feature. Whilst a weak ridge of high pressure sat over us on the 1st giving a reasonable day weather fronts connected to an 'Area of Low pressure' (ALP) (969 Mb) centred south of Iceland were pushing through and the rain was heavy. 9.5 mm fell late on the 1st/2nd and the 2nd itself saw 16.6 mm with winds upto 46 Mph. More rain, 4.5 mm on the 3rd but the fronts were moving south and once gone we had a cloudy day.

   The 4th was fairly awful and the months wettest day with 22.9 mm (0900 - 0900). A warm, moist and slow moving Sw'ly flow due to an 'Area of High Pressure' (AHP) over Spain/Biscay and an ALP to the North and west of the Uk being responsible. But as is so often the case, the 4th provided us with both the months warmest day at 15.2°c (59°F) and warmest night at 9.1°c (48°F).

   The 5th brought a brief respite with just 0.6 mm of rain on a cloudy and showery day and it was the last day of the month to reach 10.0°c - will it be the last day of the year to do so? (in 2010 it was 6th December). But now all eyes were focused on an ALP that was still off the eastern coast of America that would bring our next main taste of weather.

   The 6th and 7th brought sunny days (some fog early on the 6th) and the temp's dropped away to give us a ground frost on both nights. The rain arrived overnight 7th/8th and gave us 14.8 mm in total as the deep depression (956 Mb) with both warm and cold fronts arrived to the west of the Uk.

   The 9th had a deep ALP (961 Mb) over Cornwall and this introduced an ENE'ly wind which was circulating over the top edge of the Low and various troughs brought us a showery day.

   11th was then the worst day of the month. 32.8 mm of rain in the 24hr period. Then at 2006 Hrs on the 11th a 56 mph gust of wind, this being the highest ever gust that I have recorded in my four years here. We frequently had gusts over 50 Mph and it all seemed so reminiscent of November 2009. A deep depression (951) out in the Atlantic being responsible. The rain cleared on the 12th but that depression (now 957) was East of Scotland and still bringing us gusts upto 51 Mph.

   From the 13th we entered a slightly quieter period, there was a mix of showers and sunny intervals on the 13th, but the 14-15th were reasonable days with some welcome sunshine as we sat in a slack area of low pressure (984 Mb) that was over the UK. A weak ridge of high pressure on the 16th brought a day of watery sun, but by now the temps were starting to dip and ground frosts were becoming a regular feature as night temp's dipped.

   Both the 17th + 18th saw light and fragmented rain but with strong winds due to a slow moving ALP (967 Mb) just west of Eire, with Cumbria avoiding the main belt of rain associated to this system.

   The last ten days of the month saw at first a gradual cooling but which then became quite marked, these ten days also had a mean temp' of -0.3°c - WINTER HAD ARRIVED EARLY.

   Come the 21st an AHP (1033 Mb) was north of the UK and with an ALP (996 Mb) in Biscay a cold NE'ly flow developed (although for ourselves it was a NW'ly flow) and with the presence of trough lines we endured a cloudy and dull day and a temp of 3.8°c. The 22nd saw that easterly flow effect us and there were showers in the afternoon.

   The 23rd saw the air temp drop below freezing and so was to begin a sequence of air frosts that extended to the months end (and beyond into December and thus creating a record for this site of most consecutive days to record an air frost). A ridge of high pressure was extending south from Greenland over the UK and still with a NE'ly airflow.

   The 24th followed suit, but the 25th brought the first snow showers of the season and whilst only light it was a taste of what was to come. Now we had a northerly air flow with air originating from the USSR and that snow was the result of several trough lines.

   26th saw the cold now really take a grip with an airfrost of -6.0°c and the remaining days of the month were all similarly cold. The 28th had a ground frost of -13.0°c.

   The 27th saw us wake upto a covering of 4.5 cms of snow which had fallen in the early hours as a complex low pressure system (1001 Mb) moved south leaving clearer conditions behind it. The 27th was a lovely sunny day but became an 'ICE DAY' (a day that remains below freezing for the whole 24hrs) with a max' temp' of just -0.9°c (30.4°F) and it also provided the months lowest Min' temp' of -6.2°c (20.8°F). Snow would now become a permanent feature for the rest of the month and well into December.

   A further 1/2 cm of snow fell early on the 28th and then 3/4 cm on the 29th. We still had the same N-NE'ly airflow and with troughs circulating around the Uk we picked up the occassional shower. It should be remembered that with such airflows the eastern side of the UK gets the brunt of any snow in such conditions and that the Pennines act as a barrier that tend to limit our exposure to the worst of the conditions.

   However, a further 8cms of snow fell overnight 29/30th to leave a level depth of 11 cms at 0900 hrs on the 30th. All brought by those troughs now associated to an occluded front over Scotland. The day repeated the same theme, failing to make even 1.0°c (along with 27-29th) and we had further snow showers during the day and evening.

   A fascinating month of weather. Snow is not unusual in November, but (rarely) not to this extent and severity and certainly doesn't stick about for this amount of time.

   The Mean Temperature for the month was 3.83°c+     - the Mean Max' was 6.51°c and the Mean Min' 1.15°c.

   We had 11 Air Frosts in the month (74 for 2010) and Grass frosts totalled 19 (120 for 2010).

  COMPARISONS:-

   * November 10 rainfall was 82.4% of the November average for 07/08/09

   * November 10 was 2.93°c colder than November 2009 +

   * November saw 23 rain days of which 18 were wet days.



  * The 3 month mean for September/October/November 2010 is                   TEMP'    8.37°c         -          RAIN    305.4 mm

* September/October/November 2009 was TEMP'    9.67°c - RAIN    411.2 mm

* September/October/November 2008 was TEMP'    - RAIN    428.3 mm

* September/October/November 2007 was TEMP'    - RAIN    198.7 mm

 

* 2010 TO DATE TEMP'    8.29°c - RAIN    678.6 mm

* 2009 Jan - Nov TEMP'    9.50°c - RAIN   1171.5 mm

* 2008 Jan - Nov TEMP'    - RAIN   1290.0 mm

   + Met office figures for November show that NW England/N. Wales had a mean temp' of 4.3°c, some -1.8°c colder than the reference period 1971-2000 (-1.4°c colder than reference period 1961-90)

   PREVIOUS MONTHS REPORTS

JANUARY 2010    FEBRUARY 2010    MARCH 2010    APRIL 2010    MAY 2010    JUNE 2010    JULY 2010    AUGUST 2010    SEPTEMBER 2010    OCTOBER 2010   

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