Monthly Summary - February 2012

   February saw high pressure firmly established over or near the UK for most of the month and it was to dominate our weather virtually throughout; indeed a new record for the highest monthly mean air pressure (1027.3 Mb) was set for this site. But the position of that high pressure to the UK was key in determining how cold or warm it was; whilst the first half of the month was cold with some sharp frosts, the second half was especially mild, which, overall, created a fairly average month.

   It was also a relatively dry month but here in Cumbria a 'weather event' is never too far away and the 9th saw the rare event of 'Freezing rain' that literally brought things crashing to a halt, but with the mild weather at the month's end, winter drew to a fairly tame close. Indeed winter has been relatively mild and much warmer than the two recent winters.

   The month started where January had finished with settled and cold conditions brought by the intense High Pressure (HP) (1060Mb) anchored over the USSR which extended a ridge of HP over the UK and which acted as a block to our usual westerly flow. Whilst cold it was also sunny during the 1st-3rd and gave lovely winter days, but the night time frosts were severe with -7.8°c on the 2nd and then -8.1°c (17.4°F) with a ground frost of -11.7°c on the 3rd being the month's coldest night. Any breeze was from the SE and it felt cold in day-time temperatures typically 2-3°c.

   The 4th saw a frontal system move in off the Atlantic and as it squeezed up to the colder continental air the outcome was snow. But the picture in Cumbria was a little more complex with the snow being more widespread to the south of Penrith whilst to the north falling more as rain; even Alston saw as much rain as it did snow. This gave a fall of 4 cms that would lay on the ground until late on the 6th.

   The HP on the continent had been squeezed east but would return from the 7th; in the meantime the 6th was foggy as we sat in a slack area between weather systems. The 7-8th saw the sun and more severe cold return with -6.7°c recorded overnight 7-8th and the 8th was also the month's coldest day at 0.3°c (32.5°F) and the 9+10th would also fail to reach 1°c giving a run of cold days. Under that HP the air pressure on the 7/8th would peak at 1043.6 Mb - but the weather event of the month came on the 9th.

   Freezing rain is thankfully an uncommon occurrence, it creates treacherous conditions that are difficult to counteract - but nonetheless it is a fascinating phenomena. We still had the presence of HP and the air and ground temperatures were below freezing but now a warm front moved south out of Scotland and which would bring a little precipitation. This precipitation would have started as snow, but crucially would turn to rain as it fell through a narrow band of warmer air sat between the ground and cloud base. As this rain neared the ground it became 'super cooled' as it once again met colder air and then fell onto frozen surfaces which saw it freeze on impact giving a glazed ice that literally covered everything.

   By the middle of the afternoon the temp' rose above freezing and the worst was over. The 10-11th were then murky days as despite the presence of HP we were in between systems with weak Atlantic frontal systems sitting over us giving that murk and a little drizzle.

   From the 12th - 16th HP returned but this HP was sat in the Atlantic and whilst feeding us a NW'ly airflow over its top flank, it became milder as this airflow originated from mid latitudes. The 12th would become a foggy day after a morning of drizzle and then the 13-16th were cloudy and mild with 9.8°c (49.6°F) recorded on the 15th. However, whilst the 12th had seen the last of the night-time air frosts, ground frost still occurred on every night.

   The 17th saw the HP move south and this brought mild air on a westerly flow and would generally set the theme to the month's end. Firstly a cold front brought rain of 5.3 mm overnight 17-18th and then following a lull in the afternoon of the 18th a trough line brought a hours worth of heavy snow and wind mid afternoon, but maybe typical of the winter, it didn't settle.

   The 19th was simply a gorgeous day and we had wall to wall sun. There had been a frost overnight as the HP in the Atlantic had just nudged back north and now brought a cold NW'ly flow but the 20th saw the HP once again slip south and now the month would become SW'ly to the end.

   Through the 21st - 23rd the UK was sat in a broad warm sector and the temperature rose accordingly, becoming quite mild. But so often the price to pay for such mildness is rain and both the 21st and 22nd were poor wet days. The 21st saw a steady drizzle and overnight into the 22nd a warm front moved east off the Atlantic and brought a spell of heavy rain and strong winds gusting to 56 Mph. Using 09-0900 hrs readings the 22nd with 14.1mm was the month's wettest day. With the 8.3 mm on the 21st these two days had accounted for the major chunk of the monthly total of 37.8 mm.

   The month's warmest day came on the 23rd with 12.5°c (54.5F) as we still sat in that warm sector and the day was reasonable with some sunny intervals, but the brisk westerly flow that accompanied these few days was noticeable.

   The month then became quite flat and uneventful. There was a little rain in showers on the 27th and a foggy start to the 28th, but generally mild and cloudy conditions prevailed and even night time temperatures were well up on normal with a minimum of 8.2°c recorded overnight 27/28th. It was the presence of the HP just to our south and a low pressure system located off Iceland that kept us squeezed into a westerly flow, with the HP responsible for drawing up air from low latitudes and hence the unseasonable mildness.

 

   Rainfall totalled 37.8 mm for the month, with rain recorded on 12 days of which 7 were 'Wet days' (1.0mm +).

   The Mean Temperature for the month was 3.47°c+         --      The Mean Max' was   6.36°c   --    The Mean Min'   0.58°c.

   We had 14 Air Frosts in the month (year 25)      --      Grass frosts totalled 19 (year 39).

   The 30 cm soil temp ranged from 7.8°c on the 29th      to      1.5°c on the 10-11th      --      with a monthly mean of 3.6°c

 

COMPARISONS:-

   * February 2012 rainfall was 47.7% of the February average for 2008 - 2011

   * February 2012 was 1.61°c colder than February 2011      --      2.15°c warmer than February 2010      --      0.53°c colder than 2009



  * The 3 month mean for December/January/February 2011-2012 is              TEMP'    3.93°c         --          RAIN    308.6 mm

* December/January/February 2010-2011 was TEMP'    1.73°c -- RAIN    341.6 mm

* December/January/February 2009-2010 was TEMP'    1.20°c -- RAIN    154.0 mm

* December/January/February 2008-2009 was TEMP'    -- RAIN    346.8 mm

* December/January/February 2007-2008 was TEMP'    -- RAIN    472.4 mm

OTHER WINTER INFORMATION

   ICE DAYS = 0       (Winter 2010/11 = 13)       (Winter 2009/10 = 6)       (Winter 2008/9 = 1)      

   DAYS OF LAYING SNOW = 3       (Winter 2010/11 = 23)       (Winter 2009/10 = 32)      (Winter 2008/9 = 16)      (Winter 2007/8 = 3)

   DAYS OF FALLING SNOW = 19      (Winter 2010/11 = 20)       (Winter 2009/10 = 39)    

   AIR FROSTS = 30      (Winter 2010/11 = 40)       (Winter 2009/10 = 57)      

   GRASS FROSTS = 59      (Winter 2010/11 = 56)       (Winter 2009/10 = 81)   

 

 + Met office figures for February -- NW England/N. Wales had a mean temp' of 3.9°c, this being +0.3°c warmer than the reference period 1971-2000 (+0.9°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  

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