Out walking yesterday I took the opportunity to check on the sun’s progress in our sky using Sunseeker 3D (the sharper amongst you will notice the actual sun and the sun graphic don’t line up because I didn’t wait to calibrate the compass, must keep up my mile walking average on Fitbit you know :)) and you can see how much higher it is in the sky now (yellow line) vs. the blue line of mid-winter. It’s nice that the evenings are getting some pace on and sitting here we are two weeks to March and hopefully some nice temperatures and a growing spring. (sunshine and showers)
A real up and down temperature and rainfall week in store as we move from trough to peak to trough to peak in the space of 7 days culminating with what will be a pretty mild weekend I think for all of us. (but likely a wet one as well for some ) so without further ado, onto the weather for this week. (I have to finish my talk for the BIGGA London section tomorrow :))
General Weather Situation
Monday starts off fine and dry for many with a sharp frost and clear, blue skies, lovely. And that’s the way it looks to stay for the entire day save for some cloud cover over north east / eastern coasts and the risk of some snow showers pushing in on the back of that cloud. It’ll be a pretty cold day with light to moderate northerly wind holding back temperatures in the mid-single figures. Clear skies will put us into freezing temperatures pretty early on in the evening so another hard frost in store.
Tuesday sees a similar start for most of the U.K and Ireland, but cloud starts to build from the off across Connacht and Donegal and that heralds the arrival of rain mid-morning to the north-west of Ireland. That cloud cover will extend over Scotland to make it a duller start for the west coast of Scotland, but further south and east, it’ll be dry, bright and cold after another penetrating frost. Through the late morning that diagonal band of heavy rain (/) will cover Ireland and push into north west Scotland falling as wintry showers over higher elevations. By the evening rush hour it’ll still be situated over most of Ireland and Scotland, but will then begin to sink south into northern England, Mid and North Wales later on Tuesday night. Temperatures will be milder under that rain, high single figures possibly, but will remain in the mid-single figures for the U.K. The wind on Tuesday will be moderate to gale force over western areas (lighter further east) and swing round to the west / south-west.
Overnight into Wednesday the rain will continue to sink slowly south, so by the morning rush hour it looks likely to affect the south west of England, Wales and across to The Midlands with only the south east of England dry initially. This rain will fall as wintry showers over higher elevations. By mid-morning it has cleared Scotland and Ireland too and it remains fixed in a static band through the late afternoon and into the evening. You can see though that the south east looks at this stage to miss the worst of it on Wednesday.Temperatures will remain on the cold side across most areas so not only a wet day, but a chilly one as well, with mid to high single figures the order of the day despite a westerly, south westerly air flow. With the rain front being a slow-moving one, amounts will be significant for some areas I’m afraid.
As we progress into Thursday the rain eventually moves over the east and south east of England but as it does so it meets that colder, eastern air and we could see some snow accumulations here overnight into Thursday. So by the morning rush hour it sits in a line drawn down from The Humber to the Isle of Wight and is falling as rain, sleet and snow. Elsewhere over Ireland, Wales, Northern England and Scotland we have a dry start to Thursday and a cold one to boot with the risk of frost high again for Thursday morning. By lunchtime Thursday that band of rain, sleet and snow over south east / east England reluctantly pushes off into The North Sea though East Anglia may see that moisture extend right till dusk. Behind that rain, sleet and snow, skies clear over Ireland and the U.K to give a cold, clear night with a penetrating frost. Temperatures similar to Wednesday, mid to high single figures and for most of the U.K, a cold northerly wind will call the shots. (Further north it’ll be more westerly / south-westerly)
Closing out the week on Friday sees a band of rain into Ireland from ‘first knockings’ and this will quickly push eastwards to affect the west coast of Scotland, Wales and England. Where that rain butts up against the colder air mass we could see it readily turning to snow, particularly over higher elevations. Through the morning this band of rain stays pretty much in place, but during the afternoon it begins to sink south and east into Northern England, The Midlands to give a dull wet end to the day here and across pretty much all of the U.K and Ireland unfortunately. You may notice as we progress through the afternoon it’ll feel milder and that increase in temperatures will hold through Friday night. You’ll also notice the wind on Friday which will ramp up to moderate force and blow from the south west heralding the onset of milder air.
The outlook for the weekend looks unsettled particularly for the north and west where the change to a south westerly air stream will push rain into Ireland on Saturday morning and across western coasts of England, Wales and Scotland through the course of Saturday morning and inland as well. By afternoon that rain looks to become isolated to north-west England and south-west Scotland. Further south it’ll be drier, brighter and very much milder with temperatures right up in the early to mid-teens, quite a transition from the week. Sunday looks to be a much nicer day for everyone with strong westerly winds and sunny intervals. It’ll feel a little cooler than those Saturday highs but still into double figures across most areas. There is a potential though for more rain across north west Scotland and Ireland on Sunday p.m. but at this stage it is tricky to say.
At this stage it looks like another topsy-turvy week coming up next week with a number of weather systems coming to play. So Monday looks to start off unsettled with cool, cold north-westerly winds and these will push frequent blustery showers across Ireland, Scotland, Wales and England through the course of Monday and Tuesday. It shouldn’t be too wet from what I can see at this stage and temperatures will be high single figures, so not much to write home about really Wednesday looks to be a quieter day with high pressure exerting a brief and albeit temporary influence sadly. So dry and settled for Wednesday for most except Ireland where I think a new rain front will push in Wednesday p.m. By Thursday we see that rain clear Ireland and push south into The Midlands and south of England along with some milder temperatures I think. The end of the week looks windy, mild and unsettled with strong south westerly winds.
Looking at grass swards on my travels I’m seeing a lot of moss in the canopy and this pretty much vindicates my thinking of earlier in the year regarding the type of grass growth we produced at the back end. You’ll still remember hopefully my graphs of Growth Potential at the back end of the 2015 and how they reflected so much more growth in November and December vs. anything we’ve seen before. I’ve updated them for a couple more locations so you can see how the picture relates to other areas of the U.K and Ireland.
Interestingly you can see that although Dublin showed the same pattern as Watford, the growth level in the Watford was much higher in November and December and that’s because Central England picked up a southerly air stream rather than a cooler, wetter, westerly air stream for Ireland.
So what has this to do with Moss ?
Well logic would dictate that if the grass plant was growing so much more strongly at the back end of the year (as it shows in the G.P graphs above) this would surely lead to tipping the balance in favour of grass over moss ?
This clearly isn’t the case and I think it’s to do with the ‘type of growth’ that took place in November and particularly December. November 2015 was the dullest on record with only 18.4 hours of sunshine recorded for the whole month at the meteorological station at Reading. That compares with a normal sunshine level for November of 63 hours, so only approximately 30% of the normal sunlight. December was also a dull month with 25-35% less sunshine hours.
So we had high air temperatures, abundant moisture and low light and for me that means the type of growth that took place had a more elongated habit with less basal tillering. Effectively it’s a bit like growing a plant on your window sill, it’ll stretch towards the light source. This type of grass growth then is more upright (so you’re still having to cut a lot) and less basal and to me that means it’s less effective at out-competing moss which lives deeper down in the canopy. “What’s good for the Goose is good for the Gander” the saying goes and I think the warmer winter temperatures and ever-present moisture also encouraged a higher rate of growth for moss as well as grass. There’s not a lot of information on the growth rate of moss in the U.K and Ireland, but what I did find suggested that moss growth was significant during the winter when air temperatures were above 5°C. So a warm, wet November and December isn’t ideal for grass growth, but is for moss.
Spring Aeration – Why March and April can be tricky months…
Continuing a theme from my earlier posts this year on spring aeration and our changing climate, one of the subjects I’m covering tomorrow at the BIGGA London Section / Oaklands College seminar is how our springs of late are pretty poor for consistent grass growth. (The seminar is creatively named the 4 ‘W’s Seminar, of which I am ‘W’ no.3, no suggestions please in my case what the ‘W’ actually stands for) . For ‘Pretty poor’ grass growth, read ‘Providing poor recovery’.
Here’s a couple of interesting graphs to highlight my point from March / April 2015.
What we are looking at here are two graphs – The first maps out minimum and maximum air temperatures through March and April 2015 and the second translates that data into daily Growth Potential figures.
If you look at the two lines on the top graph these are drawn at 7.5°C and 15°C air temperature respectively. If you look at the bottom line (7.5°C), count the number of days when the air temperature at night (minimum air temperature) exceeded 7.5°C during the two months of March and April last year. The number of days was 4 out of a possible 61.
Next look at the bottom graph showing daily Growth Potential for the same period and count the days when the figure exceeded what I would call as the good growing figure cut-off of 0.6. That is to say when we measure a G.P of 0.6 we usually get very good growth in the spring. The number of days was 5 out of a possible 61.
The work above shows that in order to get good growth in the spring you either need the night temperature to exceed 7.5°C and the day temperature 15°C or the day temperature to exceed 25°C, full-stop.
This illustrates how critical good night temperatures are to consistent grass plant growth rates and therefore even if we have 20°C maximum during the day, if the night temperature is 7.5°C or below, we won’t get a daily G.P figure high enough to reflect good growth.
So if we have aeration planned for March and April as most facilities do it can often be a really slow process to gain recovery and a consistent grass sward. Bear this in mind when you’re selecting tine size / spacings or Graden blade width / depth.
Just to finish off the slightly negative vein, the first two days of The Masters at Augusta 2015 coincided with two night frosts back home and Daily Growth Potential figures of 0.3 or lower
The Week Ahead
With dry weather early on this week and a wet interlude mid-week rolling into Thursday for some places it’s a good time to get those granular applications out on areas where you want to start to push some early recovery. (Because of the milder weekend coming)
By this I mean wear pathways, thin areas of outfield turf and tees that have been on all winter. On the subject of moss control, this week is a good week to apply a granular mosskiller I’d say either before mid-week or after (once the moss is nicely wetted up)
On finer turf my only concern is the rapid temperature rise predicted by Meteoblue for Friday night / Saturday morning and this could kick in a bit of disease activity, particularly on old scarred areas of turf.
Ok that’s it for this week’s blog.
All the best.