Monthly Summary - May 2017

 Warm, dry and sunny - warmest in my 9 years of records.

  The dry start to 2017 continued in May, which was anticyclonic upto the 11th, resulting in settled and dry conditions with numerous fine and sunny days, albeit a little fresh with winds from an easterly quarter. It became unsettled mid-month followed by a notable hot spell 24-27th with three days attaining 25°c, before breaking down with thunder on the 27th, the month then ending somewhat mixed.

  The beginning of the month whilst enjoying many decent days, especially 3rd - 5th, was plagued by stiff easterly winds that kept a lid on the temperature and many nights saw a ground frost. After the 11th frost was no longer a problem with night-time minima unduly high, especially from the 24th, whilst it wasn't until the 22nd that day-time maximums showed a more noticeable upward trend, peaking during the 25-27th.

  MSLP of 1015.7 Mb was +0.8 Mb above the local average for May with high pressure dominant for lengthy periods at both ends of the month, but was much more mixed inbetween with low pressure during the 11-17th.

  Overall a mean minimum of 6.24°c and a mean maximum of 17.07°c saw the temperature 1.2°c above the 1981-2010 average and it was the warmest yet recorded at this site (9 years of records). The highest maximum temperature recorded was 25.9°c (25th), the lowest minimum -2.1°c (9th).

  Rainfall of 38.2 mm (Crosby Ravensworth School 43.6 mm  -  Castlehowe Scar 66.2 mm  -  Reagill 48.3 mm) made it the wettest May since 2015 (the 4th driest of the 10 recorded) and was 55.8% of average for 2008-16.

  Locally, rainfall percentages showed a large disparity. Within the Lake District they were typically above average (123.8% at Brothers Water), but which was solely due to an exceptionally wet day on the 15th, but outside of the Lakes the averages fell well below the norm', down to 53.1% at Haresceugh Castle (Kirkoswald).

  At the Met' Office site at Newton Rigg, 41.9 mm (74.7%) made it the wettest since 2015 and in a series back to 1900 there has been 34 drier, 81 wetter and with 2 years having the same total. In a series back to 1952 a mean temperature of 11.6°c is the coldest since 2015 with 54 having been colder, 9 warmer and 2 having the same mean temperature.

  Figures from the Environment Agency’s rainfall sites were, (figure in brackets being the monthly average for 1961-90)   ‘Data kindly provided by the Hydrometry and Telemetry team of the Environment Agency (Penrith)’:

  Kirkby Thore (Not Yet Available) (48.0 mm)

  Haresceugh Castle (Kirkoswald) 32.44 mm (61.1 mm)

  Brothers Water 170.93 mm (138 mm) and

  187.0 mm at Seathwaite Farm (Borrowdale - 169 mm [average for 1981-2010])

 

    SPRING

   Here at Maulds Meaburn, spring 2017 with 158.0 mm of rain (Crosby Ravensworth 174.2 mm) has been the driest since 2010 and is the 3rd driest of the ten now recorded. That 158.0 mm represented 78.1% of the rainfall for those nine previous springs.

   A mean temperature of 8.90°c is the warmest yet recorded (of nine), being 1.19°c warmer than the average of those previous eight.

   At Newton Rigg rainfall totalled 187.1 mm and had a mean temperature of 8.65°c. In comparison to the 1981-2010 averages this represented 101.6 % of spring rainfall and it was 0.9°c warmer than average.

   In a series back to 1900 (1 year of incomplete data), spring has been drier on 80 occasions and wetter on 36 and in a complete series back to 1956, 5 have been warmer, 54 colder with 2 having the same mean temperature.

 

    MAY

  1st - 2nd    Somehow we managed to stay dry at the start of the month, this being despite low pressure (LP) being over and surrounding the UK as we tended to avoid any associated fronts and we even got to see some sunshine. Temperatures rose to 17.0°c on the 2nd and with there always been some cloud to provide a cover, night-time minima stayed on the mild side.

  High Pressure (HP) west of Norway would begin to ridge down towards the UK during the 2nd and which would then dominate well into the month.

 

  3rd - 11th    The HP would slowly migrate west towards Iceland, then Greenland, leaving the UK at its most SE'ly extent and which would draw down a cool and strong E-NE'ly wind. Whilst the days were dry and often sunny, that wind was on the cool side and 'fresh and breezy' was the most apt term.

  In fact the 3rd-5th were lovely days with plenty of sun and little cloud - it was just that wind. Temperatures remained a fraction above 15°c, but it felt cooler in the wind; out of the wind, it almost felt like early summer.

  Now with less cloud cover, night-time temperatures started to dip and whilst ground frosts were frequent, the air temperature held up above freezing until later in the period.

 

  1200 Hrs 4th -   high pressure to the north ridging down over the UK giving sunny but fresh conditions  

    From the 7th the HP elongated W-E, but still with the UK at its SE edge and subject to a NE'ly breeze. Subsequently temperatures now took a little dip, dropping below 14° and we had also had a couple of air frosts. The 7th only attained 13.6°c (56.5°f) and whilst the 7+8th both just missed out on air frosts, the 9+10th did not.

  The skies cleared long enough during both nights for the temperature to dip and -2.1°c (28.2°f) (-5.1°c at Shap) is certainly cool for May and which recorded a grass frost of -4.4°c to test the robustness of delicate plants. The 10th only dropped to -0.2°c but those first ten days of the month had remained completely dry and cool, but with plenty of sun.

  The 11th would see areas of low pressure (LP) located to our SW and NW move slowly towards the UK, with yet another area of LP to our south pushing a warm front over the UK. The day stayed dry and with plenty of sunshine the temperature rose to 19.4°c.

 

  12th - 17th    Now the fine weather finally broke. After those eleven dry and largely sunny days, we now got some much needed rainfall as LP became dominant.

  The first rain was only light and patchy on the afternoon of the 12th with further rain overnight into the 13th. Rainfall totals were light during 12-14th and once again day-time maximum's fell below 14°c, but due to the cloud cover night-time minima remained high.

  The month's wettest day came on the 15th as LP to our SW moved more rapidly NE and pushed a series of fronts across the UK (see chart below) and rain fell consistently throughout the day to total 17.4 mm. Apart from the rain it resulted in a mild night into the 16th with a minimum of 11.2°c.

  The 15th was particularly wet in the Lake District with Seathwaite Farm recording 112.8 mm, but which was well beaten by 154 mm at Honister.

 

    Mid-day 15th -   the area of low pressure west of Eire with the series of fronts that gave the month's wettest day  

 

  18th - 23rd    The general theme remained cool and unsettled with the occasional spell of rain, usually in the form of showers, but with some sunny intervals.

  LP was still in close proximity to the UK with the occasional front or trough line giving that rain, mainly in the form of showers. The 'Azores High' was always just to the south and never able to progress north, being held at bay by the LP.

  The effect was a chilly one with day-time temperatures struggling, the 20th being the coldest day of the month at 12.7°c (54.9°f), marking the low point in the run of cool days.

  HP centred over Germany gave a lovely day on the 22nd with the temperature sneaking just over 20°c, before LP in the Atlantic pushed a cold front over the UK which then lingered during the 23rd - but now the weather would turn a take for the better.

 

  24th - 27th    HP in Biscay would now finally make progress north, becoming dominant over the UK before finally drifting away to Scandinavia. The HP drew up warm air from the continent on a SSE'ly and whilst it was relatively brief, it became hot and sunny.

Hot and Sunny - Mid-day 25th (left) and then Mid-day 26th    -    The HP that became dominant over the UK, before drifting away, but which gave a brief hot and sunny spell

                        

 

  At 21.9°c the 24th still felt warm, but now the 25-27th would all top the 25°c mark. The 25th started completely cloudless and even the morning was warm, with the day peaking at a month's high of 25.9°c (78.6°f) and whilst the 26th was even warmer in the morning (21.4°c at 1000 hrs) it fell just short of the 25th at 25.8°c!

  You could say there was a cooling trend as the 27th fell just short of the 26th with 25.7°c, but this was a different day. Already cloudy in the morning, that cloud thickened in the afternoon when it became quite close, the temperature spiking upwards for an hour just before 2 p.m. and then the inevitable thunder arrived.

  LP quickly developed on an occluded front that was strung out north-south just west of the UK. The LP initially built near Cornwall and then moved north, pushing a strong trough line ahead of it and this brought the thunder.

  As thunderstorms go it was a pitiful effort as there was very little lightning and not much rain, indeed the shower in the early evening gave more rain - the total for the day being just 3.5 mm.

 

  1200 Hrs 27th -   the low pressure that developed, pushing north and causing the breakdown to the hot spell  

 

  28th - 31st    HP was still the more dominant feature through to the month's end, but it was a little bit more mixed.

  The 28th was decent enough, still over 20°c with the day becoming increasingly sunny as HP developed just north of Eire, but fronts pushed north out of France on the 29th to give a dreary day with light rain and a notable dip in temperature, down to 14.1°c.

  More drizzle on the 30th as a cold front associated to LP in the Atlantic moved across the UK and then the month finished with a lovely day as HP once again sat over the UK.

 

May Rainfall Anomalies %                                                                                    May Temp' Anomaly   

            

 

   Rainfall totalled 38.2 mm for the month, with rain recorded on 14 days of which 8 were 'Wet days' (1.0mm +).

   The Mean Temperature for the month was 11.65°c      --      The Mean Max' was   17.07°c     --      The Mean Min'   6.24°c.

   We had 2 Air Frosts in the month (year 32)                --      Grass frosts totalled 8 (year 67).

   The 1 foot soil temp ranged from a low of 10.0°c on the 1st        to      a high of 15.8°c on the 29th     --      with a monthly mean of 12.2°c

   The 1 meter soil temp ranged from a low of 8.8°c on the 1st      to      a high of 12.2°c on the 31st     --     with a monthly mean of 10.2°c

 

COMPARISONS:-

   * May 2017 rainfall was 55.8% of the average for 2008 - 2016

   * May 2017 was 1.5°c warmer than the average for 2009 - 2016 and 1.2°c warmer than the local long term average 1981-2010

   * This makes the Jan' to May period of 2017 1.16°c warmer than the average for 2009-16 and with 65.9% of average rainfall for 2008-16

 

  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   

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JANUARY 2017    FEBRUARY 2017    MARCH 2017    APRIL 2017   

  

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The Oldest Inhabitant    An Inch Of Scotch Mist   

 

© Darren Rogers 2010-17

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