Monthly Summary - December 2013

   December presented an amiable face for the first few days, thereafter it revealed itself to be volatile, moody and tempestuous or if you prefer, wet, windy, mild and at times quite stormy.

   The month apart from a notable storm on the 5th was fairly quiet upto the 12th, but thereafter an abrupt change as a succession of deep and vigorous depressions arrived of the Atlantic. These depressions rose due to steep temperature contrasts over America and under the influence of a very active Jet Stream literally raced across the Atlantic. Subsequently daily rainfall totals were high with 3 days recording in excess of 1 inch of rain and 7 days recording wind gusts of over 50 Mph.

   Consequently with the succession of depressions mean SLP was some -5.1 Mb below average, but in such conditions frost is never an issue and indeed the month was notably mild.

   Overall a mean minimum of 3.16°c and a mean maximum of 8.33°c saw the temperature some 2.3°c above the 1981-2010 average, making it the warmest December since 1988.

   Rainfall locally was double the December average and the wettest since 2006. At Newton Rigg (199.4 mm - EA gauge) in a series back to 1914, December as been wetter on just 3 occasions (3 years of missing data.) and this is the 17th wettest of any month in that time. The 270.7 mm of rain here at Maulds Meaburn making it the second wettest of any month in my 7 years of records.

   Figures from the Enviroment Agency’s rainfall sites were, (figure in brackets being the monthly average for 1961-90): Kirkby Thore 147.6 mm (71.7 mm) , Brothers Water 599.2 mm (304 mm), Nunwick Hall 160.6 mm (78.3 mm) and 671.4 mm/26.4 inch at Seathwaite Farm (Borrowdale - 339 mm).

  ‘Data kindly provided by the Hydrometry and Telemetry team of the Enviroment Agency (Penrith)’.

 

   1st - 3rd    With high pressure (HP) dominant over the UK but drawing up mild and moist air from the Atlantic, the month started quietly with the month's coldest temperature of (only) -1.5°c. However, it was somewhat overcast and this would be a theme that would return come the 6th.

 

   4th - 5th    After rain overnight into the 4th the day became bright with some spells of sun, but that was only ahead of stormy conditions on the 5th. Low pressure north of Scotland pushed a cold front south and as that plunged south it squeezed up against the HP sat south west of the UK and the winds intensified. Gusts over 60 mph were common through the morning, peaking at 65 Mph, then the highest of 2013.

   Fortunately rainfall was insignificant and the winds eased back in the afternoon, but with the odd wintry shower.

 

  6th - 12th    And now it became unseasonably mild as the HP to our south west migrated slowly over France and then Europe and which gave a feed of brisk and mild south westerly winds. A warm front that pushed over the UK later on the 6th introduced the milder air to the UK and day-time temperatures were frequently in excess of 10°c.

   Especially notable was an overnight 'low' temperature of 9.4°c on the 9th, something more akin to early summer! The period also saw little rain but the downside was the overcast conditions brought by the modification of the sub tropical air due to its long journey over the sea to our shores.

 

   13th - 24th    Whilst tending to remain mild it now became increasingly wet and stormy as a succession of vigorous Atlantic depressions rattled through in quick succession.

   Once again the position of the Jet Stream came to the fore as it was responsible for the feed of those depressions. The 13th was the month's warmest day at 11.2°c but was also wet and then the intensity of the rainfall increased from now on to the month's end.

   The 14th saw 28.4 mm and gusts to 54 Mph (Shap 44.4 mm) on the first depression to arrive in the period, followed by 16.8 mm 15th.

   The pressure gradient slackened sufficiently overnight into the 17th to give a slight ground frost, -0.3°c and then a reasonable but cooler day. This was only ahead of the next depression 18th that gave 19.1 mm and winds to 56 Mph as the cold front moved through during the evening with the glass dropping to 978.5 Mb.

   As that system cleared into the 19th it remained windy but became cooler behind and we saw a mix of wintry showers.

   There was no let up as LP sat to the south of Iceland fed cold fronts over the UK during the afternoon and peaking in the evening of the 20th, depositing 42.0 mm (1.65 inch) and again with gusts over 50 Mph.

   And this marked the first of four especially wet days with the 20th-23rd recording a total of 114.6 mm, that's an average of 1.13 inches of rain per day!

   The 21st notched up 23.4 mm as that LP near Iceland still dominated and after a 'quiet day' 22nd with just 3.9 mm of rain with some wintry showers in a brisk westerly flow, there was still the month's wettest day to come.

   Unlike the 21st and 22nd, the 23rd didn't quite get the 50 mph gusts of wind, but it did get 45.3 mm of rain and what is now the 7th wettest day recorded at this site. A rapidly deepening LP system was racing across the Atlantic and in which the pressure would drop by 42.4 Mb in 24 hours. Air pressure dropped to 937 Mb in South Uist, Hebrides (the lowest authenticated MSL pressure in the British Isles since 8 December 1886) and here at Maulds Meaburn to 960.6 Mb, the lowest locally since 10th March 2008.

   The rain was incessant and falling onto already saturated ground caused some local flooding and there followed gusts to 56 mph in the early hours of the 24th with wintry showers later in the day.

 

  25th - 26th    At least Christmas itself was pleasant enough as we got to enjoy two reasonable days. The LP cleared away and the pressure gradient slackened and thus the winds eased back and we actually saw some sunny intervals over the two days. However, rain arrived late on Boxing day as a new LP system arrived and this was one quite brutal.

 

  27th    With a central pressure of 944 Mb, locally in the range 958-962 Mb, but significantly with a more southerly track than the storm of the 23rd, this storm saw some of the stronger winds affecting Cumbria.

   The LP pushed frontal systems across the UK and the winds intensified during the late morning to gusts of 66 Mph on what became the windiest day yet recorded here. A mean wind speed for the entire day of 29.7 Mph is significant and at its peak the 10 minute average wind speed reached 41 mph (gale force).

   Rainfall from this event totalled another 17 mm and yet more local flooding followed.

 

  28th - 29th    The pressure gradient again eased as the LP system of the 27th moved away and both days were quieter and clearer with some sunny spells. However, a new LP system arrived late evening of the 29th and which would give heavy rain (19.3 mm) overnight into the 30th.

 

  30th - 31st    With the LP arriving late on the 29th the month then finished wet and unsettled! The same LP sat in the north Atlantic and after the frontal system on the 30th which gave a poor day, the 31st remained wet but with a few brighter moments.

 

   Rainfall totalled 270.7 mm for the month, with rain recorded on 24 days of which 22 were 'Wet days' (1.0mm +).

   The Mean Temperature for the month was 5.74°c      --      The Mean Max' was   8.33°c     --      The Mean Min'   3.16°c.

   We had 2 Air Frosts in the month (year 83)                  --      Grass frosts totalled 13 (year 136).

   The 1 foot soil temp ranged from a low of 4.6°c on the 26-27th         to      a high of 7.4°c on the 16th     --      with a monthly mean of 6.0°c

   The 1 meter soil temp ranged from a low of 6.4°c on the 31st      to      a high of 8.0°c on the 1st and 5th     --     with a monthly mean of 7.4°c

 

COMPARISONS:-

   * December 2013 rainfall was 206.5 of the December average for 2007 - 2012

   * December 2013 was 3.85°c warmer than the December average for 2009 - 2012 and 2.25°c warmer than the local long term average 1981-2010



  * The 3 month mean for October/November/December 2013 is              TEMP'     7.08°c         --          RAIN    528.8 mm

* October/November/December 2012 was TEMP'     5.30°c -- RAIN    547.4 mm

* October/November/December 2011 was TEMP'     7.82°c -- RAIN    400.9 mm

* October/November/December 2010 was TEMP'     3.51°c -- RAIN    241.8 mm

* October/November/December 2009 was TEMP'     6.18°c -- RAIN    472.6 mm

* October/November/December 2008 was     -- RAIN    395.6 mm

* October/November/December 2007 was     -- RAIN    283.3 mm

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* 2013 TEMP'     8.49°c -- RAIN   1232.1 mm

* 2012 TEMP'     8.26°c -- RAIN   1415.9 mm

* 2011 TEMP'     9.17°c -- RAIN   1305.4 mm

* 2010 TEMP'     7.42°c -- RAIN    702.9 mm

* 2009 TEMP'     8.84°c -- RAIN   1264.5 mm

* 2008     -- RAIN   1381.3 mm

   PREVIOUS MONTHS REPORTS

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

JANUARY 2011    FEBRUARY 2011    MARCH 2011    APRIL 2011    MAY 2011    JUNE 2011    JULY 2011    AUGUST 2011    SEPTEMBER 2011    OCTOBER 2011    NOVEMBER 2011    DECEMBER 2011   

JANUARY 2012    FEBRUARY 2012    MARCH 2012    APRIL 2012    MAY 2012    JUNE 2012    JULY 2012    AUGUST 2012    SEPTEMBER 2012    OCTOBER 2012    NOVEMBER 2012    DECEMBER 2012    SUMMER 2012    REVIEW OF 2012   

JANUARY 2013    FEBRUARY 2013    MARCH 2013    APRIL 2013    MAY 2013    JUNE 2013    JULY 2013    AUGUST 2013    SEPTEMBER 2013    OCTOBER 2013    NOVEMBER 2013    REVIEW OF 2013   

   © Darren Rogers 2012

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