Monthly Summary - March 2012

   March was simply super. It was generally settled, although a little flat at times, as for a second successive month High Pressure (HP) took full control making for a record anticyclonic spell. There were a few brief unsettled spells during the first half of the month and on the 17th, but the final ten days brought warm continental air, sun, some amazingly high temperatures and the first month of spring was an early taste of summer!

   What made this burst of warmth notable was not necessarily how early in the season it came, which in itself is rare, but not unprecedented, was its duration. The high of 21.9°c (71.4°F) on the 27th would have been the 7th warmest day in the summer of 2011 (11th warmest in the year)!

   The first half of the month did see the occasional weather fronts make some headway against the HP and bring with it some rain, but then HP would resume control and overall it was the driest month since May 2010 and by the month's end we had had 14 successive days without any rain and subsequently just a day short of an 'Absolute Drought'.

   The month started with High Pressure (HP) (1026 Mb) over northern France in control and this gave settled conditions with the 1st-2nd being generally hazy with a weak sun. A weak warm front brought a little light rain in the evening of the 1st and then the 3rd-4th saw more in the way of rain (6.6 mm - 3rd) as an occluded front followed by a cold front circulating off Low Pressure (LP) (995 Mb) to the west of Eire brought that rain with cooler, showery conditions following. Showery conditions on the 3rd but with a more organised band of rain through the early hours of the 4th.

   But already on the 4th the next area of HP was moving north from the Atlantic and this gave a cooler NW'ly flow over its top edge and there was some sleet mixed in with the rain and at 4.9°c (40.8°F) the 4th was the coldest day of the month. That HP gave settled conditions for the 5th and a.m. on the 6th and with it successive air frosts with the -3.1°c (26.5°F) the month's coldest night.

   The 5-6th were both beautiful sunny days as well, but now that HP gave way to LP approaching from off the Atlantic. Rain and wind arrived late evening on the 6th and gave 6.9 mm as both warm and cold fronts connected to a double centred area of LP near Iceland moved through. The 7th became a showery day, some of sleet in the afternoon, once those fronts had passed over.

   But it was then once again the turn of HP to take control and this would remain until the 16th. The HP moved north out of Biscay and for the 8-10th it had a brisk W'ly flow around its western flank and hence cloudy but bright conditions prevailed but then the 10-11th saw more in the way of sunny intervals as that HP had nudged that bit further north.

   It all came a little bit flat after that, but it remained settled and dry with fairly average temperatures through to the 16th when there was a very brief break in the weather.

   On the 16th the HP slipped east which allowed an Atlantic depression to progress east and this brought 4.1 mm of rain in the afternoon. The 17th was a mixed bag as numerous trough lines lay behind the cold front from the 16th and this brought showers of rain and for 30 minutes from 1130 hrs a very heavy shower of hail. This briefly gave a covering on most surfaces and the day resorted to showers of rain and hence the 17th with 8.5 mm became the month's wettest day.

   But from the 18th HP would remain the dominant feature to the month's end and with it that remarkable warm spell.

   HP in Biscay was building and extended a slight ridge towards us for the 18th and this gave a beautiful sunny day. Initially as that HP built and moved north it brought a SW'ly flow over its western flank and hence it was breezy, a little cloudy although with some brighter moments has the source origin of the airflow was a mild tropical.

   By the 21st the HP was more developed and from the 22nd the temperatures started to rise more markedly. The HP was now to the east of the UK and this drew up warm and dry continental air on a SE'ly flow. Temperatures on the 22nd-23rd ranged 15-16°c, but that became 19.1°c and 19.8°c for the 24-25th and the best was still to come!

   From the 22nd the HP was centred over the UK - sunshine was dominant although a little hazy at times, but now the mercury rose high and the 26th saw a temperature of 21.0°c (69.8°F) - the earliest spring date at this site to attain 20°c and then the 27th with 21.9°c was even warmer and the sun shone bright.

   Whilst there was only three air frosts in the month, ground frost was common (19 nights) and whilst there was only one air frost (22nd at -0.6°c) in this warm period, there were ground frosts on every night 22nd-29th. Whilst the days were warm the temperature quickly dipped after sunset and the month's warmest day also created a new record for this site for the widest diurnal range. The minimum temp' of 1.8°c on the 27th saw a range of 20.1°c on that day.

   The HP started to migrate west from the 28th and the flow became more NW'ly over its eastern flank and the temp's started to dip, but the sun still shone and temps' in the range 15-18°c were still very high for this time of year.

   The month ended on a cloudy and chillier note as there was now a more pronounced N'ly flow with the HP now mid Atlantic and thus heralded a change in the weather to something much cooler.

   My observation bunch of daffodils bloomed on the 19th this year - previous years are: 2011 = 25th March + 2010 = 7th April.

 

   Rainfall totalled 31.2 mm for the month, with rain recorded on 9 days of which 6 were 'Wet days' (1.0mm +).

   The Mean Temperature for the month was 7.7°c+         --      The Mean Max' was   12.01°c   --    The Mean Min'   3.39°c.

   We had 3 Air Frosts in the month (year 28)      --      Grass frosts totalled 19 (year 58).

   The 30 cm soil temp ranged from a high of 9.6°c on the 28th and 31st      to      a low of 5.4°c on the 6th      --      with a monthly mean of 7.7°c

   The 1 meter soil temp ranged from a high of 8.3°c on the 29th      to      a low of 6.5°c on the 1st and 8-10th      --      with a monthly mean of 7.1°c

 

COMPARISONS:-

   * March 2012 rainfall was 39.1% of the March average for 2008 - 2011

   * March 2012 was 2.15°c warmer than March 2011      --      2.92°c warmer than March 2010      --      2.17°c warmer than 2009



  * The 3 month mean for January/February/March 2012 is                   TEMP'    5.04°c         --          RAIN    159.7 mm

* January/February/March 2011 was TEMP'    4.32°c -- RAIN    377.2 mm

* January/February/March 2010 was TEMP'    2.18°c -- RAIN    140.6 mm

* January/February/March 2009 was TEMP'    4.24°c -- RAIN    299.3 mm

* January/February/March 2008 was TEMP'    -- RAIN    450.8 mm

 + Met office figures for March -- NW England/N. Wales had a mean temp' of 7.9°c, this being +2.7°c warmer than the reference period 1971-2000 (+3.2°c warmer 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    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  

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